/*
 * Copyright 2008, Axel Dörfler, axeld@pinc-software.de. All rights reserved.
 * Distributed under the terms of the MIT License.
 */


#include "device_manager.h"

#include <new>
#include <set>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include <KernelExport.h>
#include <Locker.h>
#include <module.h>
#include <PCI.h>

#include <fs/KPath.h>
#include <util/AutoLock.h>
#include <util/DoublyLinkedList.h>
#include <util/Stack.h>

#include "bus.h"

#define TRACE(a) dprintf a

#define DEVICE_MANAGER_ROOT_NAME "system/devices_root/driver_v1"

extern struct device_module_info gDeviceModuleInfo;
extern struct driver_module_info gDriverModuleInfo;
extern struct device_module_info gGenericVideoDeviceModuleInfo;
extern struct driver_module_info gGenericVideoDriverModuleInfo;
extern struct device_module_info gSpecificVideoDeviceModuleInfo;
extern struct driver_module_info gSpecificVideoDriverModuleInfo;
extern struct driver_module_info gBusModuleInfo;
extern struct driver_module_info gBusDriverModuleInfo;

extern "C" status_t _add_builtin_module(module_info *info);
extern "C" status_t _get_builtin_dependencies(void);
extern bool gDebugOutputEnabled;
        // from libkernelland_emu.so

struct device_attr_private : device_attr,
                DoublyLinkedListLinkImpl<device_attr_private> {
                                                device_attr_private();
                                                device_attr_private(const device_attr& attr);
                                                ~device_attr_private();

                        status_t        InitCheck();
                        status_t        CopyFrom(const device_attr& attr);

        static  int                     Compare(const device_attr* attrA,
                                                        const device_attr *attrB);

private:
                        void            _Unset();
};

typedef DoublyLinkedList<device_attr_private> AttributeList;

// I/O resource
typedef struct io_resource_info {
        struct io_resource_info *prev, *next;
        device_node*            owner;                  // associated node; NULL for temporary allocation
        io_resource                     resource;               // info about actual resource
} io_resource_info;

class Device : public DoublyLinkedListLinkImpl<Device> {
public:
                                                        Device(device_node* node, const char* path,
                                                                const char* moduleName);
                                                        ~Device();

                        status_t                InitCheck() const;

                        device_node*    Node() const { return fNode; }
                        const char*             Path() const { return fPath; }
                        const char*             ModuleName() const { return fModuleName; }

                        status_t                InitDevice();
                        void                    UninitDevice();

                        device_module_info* DeviceModule() const { return fDeviceModule; }
                        void*                   DeviceData() const { return fDeviceData; }

private:
        device_node*                    fNode;
        const char*                             fPath;
        const char*                             fModuleName;

        int32                                   fInitialized;
        device_module_info*             fDeviceModule;
        void*                                   fDeviceData;
};

typedef DoublyLinkedList<Device> DeviceList;
typedef DoublyLinkedList<device_node> NodeList;

struct device_node : DoublyLinkedListLinkImpl<device_node> {
                                                        device_node(const char* moduleName,
                                                                const device_attr* attrs,
                                                                const io_resource* resources);
                                                        ~device_node();

                        status_t                InitCheck() const;

                        const char*             ModuleName() const { return fModuleName; }
                        device_node*    Parent() const { return fParent; }
                        AttributeList&  Attributes() { return fAttributes; }
                        const AttributeList& Attributes() const { return fAttributes; }

                        status_t                InitDriver();
                        bool                    UninitDriver();
                        void                    UninitUnusedDriver();

                        // The following two are only valid, if the node's driver is
                        // initialized
                        driver_module_info* DriverModule() const { return fDriver; }
                        void*                   DriverData() const { return fDriverData; }

                        void                    AddChild(device_node *node);
                        void                    RemoveChild(device_node *node);
                        const NodeList& Children() const { return fChildren; }
                        void                    DeviceRemoved();

                        status_t                Register(device_node* parent);
                        status_t                Probe(const char* devicePath, uint32 updateCycle);
                        bool                    IsRegistered() const { return fRegistered; }
                        bool                    IsInitialized() const { return fInitialized > 0; }
                        uint32                  Flags() const { return fFlags; }

                        void                    Acquire();
                        bool                    Release();

                        const DeviceList& Devices() const { return fDevices; }
                        void                    AddDevice(Device* device);
                        void                    RemoveDevice(Device* device);

                        int                             CompareTo(const device_attr* attributes) const;
                        device_node*    FindChild(const device_attr* attributes) const;
                        device_node*    FindChild(const char* moduleName) const;

                        void                    Dump(int32 level = 0);

private:
                        status_t                _RegisterFixed(uint32& registered);
                        bool                    _AlwaysRegisterDynamic();
                        status_t                _AddPath(Stack<KPath*>& stack, const char* path,
                                                                const char* subPath = NULL);
                        status_t                _GetNextDriverPath(void*& cookie, KPath& _path);
                        status_t                _GetNextDriver(void* list,
                                                                driver_module_info*& driver);
                        status_t                _FindBestDriver(const char* path,
                                                                driver_module_info*& bestDriver,
                                                                float& bestSupport,
                                                                device_node* previous = NULL);
                        status_t                _RegisterPath(const char* path);
                        status_t                _RegisterDynamic(device_node* previous = NULL);
                        status_t                _RemoveChildren();
                        device_node*    _FindCurrentChild();
                        void                    _ReleaseWaiting();

        device_node*                    fParent;
        NodeList                                fChildren;
        int32                                   fRefCount;
        int32                                   fInitialized;
        bool                                    fRegistered;
        uint32                                  fFlags;
        float                                   fSupportsParent;
        uint32                                  fLastUpdateCycle;

        const char*                             fModuleName;

        driver_module_info*             fDriver;
        void*                                   fDriverData;

        DeviceList                              fDevices;
        AttributeList                   fAttributes;
};

// flags in addition to those specified by B_DEVICE_FLAGS
enum node_flags {
        NODE_FLAG_REGISTER_INITIALIZED  = 0x00010000,
        NODE_FLAG_DEVICE_REMOVED                = 0x00020000,
        NODE_FLAG_OBSOLETE_DRIVER               = 0x00040000,
        NODE_FLAG_WAITING_FOR_DRIVER    = 0x00080000,

        NODE_FLAG_PUBLIC_MASK                   = 0x0000ffff
};

device_manager_info *gDeviceManager;

static device_node *sRootNode;
static recursive_lock sLock;

static uint32 sDriverUpdateCycle = 1;
        // this is a *very* basic devfs emulation


//      #pragma mark -


static device_attr_private*
find_attr(const device_node* node, const char* name, bool recursive,
        type_code type)
{
        do {
                AttributeList::ConstIterator iterator
                        = node->Attributes().GetIterator();

                while (iterator.HasNext()) {
                        device_attr_private* attr = iterator.Next();

                        if (type != B_ANY_TYPE && attr->type != type)
                                continue;

                        if (!strcmp(attr->name, name))
                                return attr;
                }

                node = node->Parent();
        } while (node != NULL && recursive);

        return NULL;
}


static void
put_level(int32 level)
{
        while (level-- > 0)
                dprintf("   ");
}


static void
dump_attribute(device_attr* attr, int32 level)
{
        if (attr == NULL)
                return;

        put_level(level + 2);
        dprintf("\"%s\" : ", attr->name);
        switch (attr->type) {
                case B_STRING_TYPE:
                        dprintf("string : \"%s\"", attr->value.string);
                        break;
                case B_INT8_TYPE:
                case B_UINT8_TYPE:
                        dprintf("uint8 : %u (%#x)", attr->value.ui8, attr->value.ui8);
                        break;
                case B_INT16_TYPE:
                case B_UINT16_TYPE:
                        dprintf("uint16 : %u (%#x)", attr->value.ui16, attr->value.ui16);
                        break;
                case B_INT32_TYPE:
                case B_UINT32_TYPE:
                        dprintf("uint32 : %lu (%#lx)", attr->value.ui32, attr->value.ui32);
                        break;
                case B_INT64_TYPE:
                case B_UINT64_TYPE:
                        dprintf("uint64 : %Lu (%#Lx)", attr->value.ui64, attr->value.ui64);
                        break;
                default:
                        dprintf("raw data");
        }
        dprintf("\n");
}


static void
uninit_unused()
{
        puts("uninit unused");
        RecursiveLocker _(sLock);
        sRootNode->UninitUnusedDriver();
}


static status_t
probe_path(const char* path)
{
        printf("probe path \"%s\"\n", path);
        RecursiveLocker _(sLock);
        return sRootNode->Probe(path, sDriverUpdateCycle);
}


static void
close_path(void* cookie)
{
        Device* device = (Device*)cookie;
        if (device == NULL)
                return;

        printf("close path \"%s\" (node %p)\n", device->Path(), device->Node());
        device->UninitDevice();
}


static Device*
get_device(device_node* node, const char* path)
{
        DeviceList::ConstIterator iterator = node->Devices().GetIterator();
        while (iterator.HasNext()) {
                Device* device = iterator.Next();
                if (!strcmp(device->Path(), path)) {
                        status_t status = device->InitDevice();
                        if (status != B_OK) {
                                printf("opening path \"%s\" failed: %s\n", path,
                                        strerror(status));
                                return NULL;
                        }

                        printf("open path \"%s\" (node %p)\n", device->Path(),
                                device->Node());
                        return device;
                }
        }

        // search in children

        NodeList::ConstIterator nodeIterator = node->Children().GetIterator();
        while (nodeIterator.HasNext()) {
                device_node* child = nodeIterator.Next();

                Device* device = get_device(child, path);
                if (device != NULL)
                        return device;
        }

        return NULL;
}


static void*
open_path(const char* path)
{
        return get_device(sRootNode, path);
}


//      #pragma mark - Device Manager module API


static status_t
rescan_node(device_node* node)
{
        return B_ERROR;
}


static status_t
register_node(device_node* parent, const char* moduleName,
        const device_attr* attrs, const io_resource* ioResources,
        device_node** _node)
{
        if ((parent == NULL && sRootNode != NULL) || moduleName == NULL)
                return B_BAD_VALUE;

        if (parent != NULL && parent->FindChild(attrs) != NULL) {
                // A node like this one already exists for this parent
                return B_NAME_IN_USE;
        }

        // TODO: handle I/O resources!

        device_node *newNode = new(std::nothrow) device_node(moduleName, attrs,
                ioResources);
        if (newNode == NULL)
                return B_NO_MEMORY;

        TRACE(("%p: register node \"%s\", parent %p\n", newNode, moduleName,
                parent));

        RecursiveLocker _(sLock);

        status_t status = newNode->InitCheck();
        if (status != B_OK)
                goto err1;

#if 0
        // The following is done to reduce the stack usage of deeply nested
        // child device nodes.
        // There is no other need to delay the complete registration process
        // the way done here. This approach is also slightly different as
        // the registration might fail later than it used in case of errors.

        if (!parent->IsRegistered()) {
                // The parent has not been registered completely yet - child
                // registration is deferred to the parent registration
                return B_OK;
        }
#endif

        status = newNode->Register(parent);
        if (status < B_OK) {
                parent->RemoveChild(newNode);
                goto err1;
        }

        if (_node)
                *_node = newNode;

        return B_OK;

err1:
        newNode->Release();
        return status;
}


/*!     Unregisters the device \a node.

        If the node is currently in use, this function will return B_BUSY to
        indicate that the node hasn't been removed yet - it will still remove
        the node as soon as possible.
*/
static status_t
unregister_node(device_node* node)
{
        TRACE(("unregister_node(node %p)\n", node));
        RecursiveLocker _(sLock);

        bool initialized = node->IsInitialized();

        node->DeviceRemoved();

        return initialized ? B_BUSY : B_OK;
}


static status_t
get_driver(device_node* node, driver_module_info** _module, void** _data)
{
        if (node->DriverModule() == NULL)
                return B_NO_INIT;

        if (_module != NULL)
                *_module = node->DriverModule();
        if (_data != NULL)
                *_data = node->DriverData();

        return B_OK;
}


static device_node*
get_root_node(void)
{
        if (sRootNode != NULL)
                sRootNode->Acquire();

        return sRootNode;
}


static status_t
get_next_child_node(device_node* parent, const device_attr* attributes,
        device_node** _node)
{
        RecursiveLocker _(sLock);

        NodeList::ConstIterator iterator = parent->Children().GetIterator();
        device_node* last = *_node;

        // skip those we already traversed
        while (iterator.HasNext() && last != NULL) {
                device_node* node = iterator.Next();

                if (node != last)
                        continue;
        }

        // find the next one that fits
        while (iterator.HasNext()) {
                device_node* node = iterator.Next();

                if (!node->IsRegistered())
                        continue;

                if (!node->CompareTo(attributes)) {
                        if (last != NULL)
                                last->Release();

                        node->Acquire();
                        *_node = node;
                        return B_OK;
                }
        }

        if (last != NULL)
                last->Release();

        return B_ENTRY_NOT_FOUND;
}


static device_node*
get_parent_node(device_node* node)
{
        if (node == NULL)
                return NULL;

        RecursiveLocker _(sLock);

        device_node* parent = node->Parent();
        parent->Acquire();

        return parent;
}


static void
put_node(device_node* node)
{
        RecursiveLocker _(sLock);
        node->Release();
}


static status_t
publish_device(device_node *node, const char *path, const char *moduleName)
{
        if (path == NULL || !path[0] || moduleName == NULL || !moduleName[0])
                return B_BAD_VALUE;

        RecursiveLocker _(sLock);
        dprintf("publish device: node %p, path %s, module %s\n", node, path,
                moduleName);

        Device* device = new(std::nothrow) Device(node, path, moduleName);
        if (device == NULL)
                return B_NO_MEMORY;

        if (device->InitCheck() != B_OK) {
                delete device;
                return B_NO_MEMORY;
        }

        node->AddDevice(device);
        return B_OK;
}


static status_t
unpublish_device(device_node *node, const char *path)
{
        if (path == NULL)
                return B_BAD_VALUE;

        RecursiveLocker _(sLock);

        DeviceList::ConstIterator iterator = node->Devices().GetIterator();
        while (iterator.HasNext()) {
                Device* device = iterator.Next();
                if (!strcmp(device->Path(), path)) {
                        node->RemoveDevice(device);
                        delete device;
                        return B_OK;
                }
        }

        return B_ENTRY_NOT_FOUND;
}


static status_t
get_attr_uint8(const device_node* node, const char* name, uint8* _value,
        bool recursive)
{
        if (node == NULL || name == NULL || _value == NULL)
                return B_BAD_VALUE;

        device_attr_private* attr = find_attr(node, name, recursive, B_UINT8_TYPE);
        if (attr == NULL)
                return B_NAME_NOT_FOUND;

        *_value = attr->value.ui8;
        return B_OK;
}


static status_t
get_attr_uint16(const device_node* node, const char* name, uint16* _value,
        bool recursive)
{
        if (node == NULL || name == NULL || _value == NULL)
                return B_BAD_VALUE;

        device_attr_private* attr = find_attr(node, name, recursive, B_UINT16_TYPE);
        if (attr == NULL)
                return B_NAME_NOT_FOUND;

        *_value = attr->value.ui16;
        return B_OK;
}


static status_t
get_attr_uint32(const device_node* node, const char* name, uint32* _value,
        bool recursive)
{
        if (node == NULL || name == NULL || _value == NULL)
                return B_BAD_VALUE;

        device_attr_private* attr = find_attr(node, name, recursive, B_UINT32_TYPE);
        if (attr == NULL)
                return B_NAME_NOT_FOUND;

        *_value = attr->value.ui32;
        return B_OK;
}


static status_t
get_attr_uint64(const device_node* node, const char* name,
        uint64* _value, bool recursive)
{
        if (node == NULL || name == NULL || _value == NULL)
                return B_BAD_VALUE;

        device_attr_private* attr = find_attr(node, name, recursive, B_UINT64_TYPE);
        if (attr == NULL)
                return B_NAME_NOT_FOUND;

        *_value = attr->value.ui64;
        return B_OK;
}


static status_t
get_attr_string(const device_node* node, const char* name,
        const char** _value, bool recursive)
{
        if (node == NULL || name == NULL || _value == NULL)
                return B_BAD_VALUE;

        device_attr_private* attr = find_attr(node, name, recursive, B_STRING_TYPE);
        if (attr == NULL)
                return B_NAME_NOT_FOUND;

        *_value = attr->value.string;
        return B_OK;
}


static status_t
get_attr_raw(const device_node* node, const char* name, const void** _data,
        size_t* _length, bool recursive)
{
        if (node == NULL || name == NULL || (_data == NULL && _length == NULL))
                return B_BAD_VALUE;

        device_attr_private* attr = find_attr(node, name, recursive, B_RAW_TYPE);
        if (attr == NULL)
                return B_NAME_NOT_FOUND;

        if (_data != NULL)
                *_data = attr->value.raw.data;
        if (_length != NULL)
                *_length = attr->value.raw.length;
        return B_OK;
}


static status_t
get_next_attr(device_node* node, device_attr** _attr)
{
        if (node == NULL)
                return B_BAD_VALUE;

        device_attr_private* next;
        device_attr_private* attr = *(device_attr_private**)_attr;

        if (attr != NULL) {
                // next attribute
                next = attr->GetDoublyLinkedListLink()->next;
        } else {
                // first attribute
                next = node->Attributes().First();
        }

        *_attr = next;

        return next ? B_OK : B_ENTRY_NOT_FOUND;
}


static struct device_manager_info sDeviceManagerModule = {
        {
                B_DEVICE_MANAGER_MODULE_NAME,
                0,
                NULL
        },

        // device nodes
        rescan_node,
        register_node,
        unregister_node,
        get_driver,
        get_root_node,
        get_next_child_node,
        get_parent_node,
        put_node,

        // devices
        publish_device,
        unpublish_device,

        // attributes
        get_attr_uint8,
        get_attr_uint16,
        get_attr_uint32,
        get_attr_uint64,
        get_attr_string,
        get_attr_raw,
        get_next_attr,
};


//      #pragma mark - device_attr


device_attr_private::device_attr_private()
{
        name = NULL;
        type = 0;
        value.raw.data = NULL;
        value.raw.length = 0;
}


device_attr_private::device_attr_private(const device_attr& attr)
{
        CopyFrom(attr);
}


device_attr_private::~device_attr_private()
{
        _Unset();
}


status_t
device_attr_private::InitCheck()
{
        return name != NULL ? B_OK : B_NO_INIT;
}


status_t
device_attr_private::CopyFrom(const device_attr& attr)
{
        name = strdup(attr.name);
        if (name == NULL)
                return B_NO_MEMORY;

        type = attr.type;

        switch (type) {
                case B_UINT8_TYPE:
                case B_UINT16_TYPE:
                case B_UINT32_TYPE:
                case B_UINT64_TYPE:
                        value.ui64 = attr.value.ui64;
                        break;

                case B_STRING_TYPE:
                        if (attr.value.string != NULL) {
                                value.string = strdup(attr.value.string);
                                if (value.string == NULL) {
                                        _Unset();
                                        return B_NO_MEMORY;
                                }
                        } else
                                value.string = NULL;
                        break;

                case B_RAW_TYPE:
                        value.raw.data = malloc(attr.value.raw.length);
                        if (value.raw.data == NULL) {
                                _Unset();
                                return B_NO_MEMORY;
                        }

                        value.raw.length = attr.value.raw.length;
                        memcpy((void*)value.raw.data, attr.value.raw.data,
                                attr.value.raw.length);
                        break;

                default:
                        return B_BAD_VALUE;
        }

        return B_OK;
}


void
device_attr_private::_Unset()
{
        if (type == B_STRING_TYPE)
                free((char*)value.string);
        else if (type == B_RAW_TYPE)
                free((void*)value.raw.data);

        free((char*)name);

        name = NULL;
        value.raw.data = NULL;
        value.raw.length = 0;
}


/*static*/ int
device_attr_private::Compare(const device_attr* attrA, const device_attr *attrB)
{
        if (attrA->type != attrB->type)
                return -1;

        switch (attrA->type) {
                case B_UINT8_TYPE:
                        return (int)attrA->value.ui8 - (int)attrB->value.ui8;

                case B_UINT16_TYPE:
                        return (int)attrA->value.ui16 - (int)attrB->value.ui16;

                case B_UINT32_TYPE:
                        if (attrA->value.ui32 > attrB->value.ui32)
                                return 1;
                        if (attrA->value.ui32 < attrB->value.ui32)
                                return -1;
                        return 0;

                case B_UINT64_TYPE:
                        if (attrA->value.ui64 > attrB->value.ui64)
                                return 1;
                        if (attrA->value.ui64 < attrB->value.ui64)
                                return -1;
                        return 0;

                case B_STRING_TYPE:
                        return strcmp(attrA->value.string, attrB->value.string);

                case B_RAW_TYPE:
                        if (attrA->value.raw.length != attrB->value.raw.length)
                                return -1;

                        return memcmp(attrA->value.raw.data, attrB->value.raw.data,
                                attrA->value.raw.length);
        }

        return -1;
}


//      #pragma mark - Device


Device::Device(device_node* node, const char* path, const char* moduleName)
        :
        fNode(node),
        fInitialized(0),
        fDeviceModule(NULL),
        fDeviceData(NULL)
{
        fPath = strdup(path);
        fModuleName = strdup(moduleName);
}


Device::~Device()
{
        free((char*)fPath);
        free((char*)fModuleName);
}


status_t
Device::InitCheck() const
{
        return fPath != NULL && fModuleName != NULL ? B_OK : B_NO_MEMORY;
}


status_t
Device::InitDevice()
{
        if ((fNode->Flags() & NODE_FLAG_DEVICE_REMOVED) != 0) {
                // TODO: maybe the device should be unlinked in devfs, too
                return ENODEV;
        }
        if ((fNode->Flags() & NODE_FLAG_WAITING_FOR_DRIVER) != 0)
                return B_BUSY;

        if (fInitialized++ > 0) {
                fNode->InitDriver();
                        // acquire another reference to our parent as well
                return B_OK;
        }

        status_t status = get_module(ModuleName(), (module_info**)&fDeviceModule);
        if (status == B_OK) {
                // our parent always has to be initialized
                status = fNode->InitDriver();
        }
        if (status < B_OK) {
                fInitialized--;
                return status;
        }

        if (fDeviceModule->init_device != NULL)
                status = fDeviceModule->init_device(fNode->DriverData(), &fDeviceData);

        if (status < B_OK) {
                fNode->UninitDriver();
                fInitialized--;

                put_module(ModuleName());
                fDeviceModule = NULL;
                fDeviceData = NULL;
        }

        return status;
}


void
Device::UninitDevice()
{
        if (fInitialized-- > 1) {
                fNode->UninitDriver();
                return;
        }

        TRACE(("uninit driver for node %p\n", this));

        if (fDeviceModule->uninit_device != NULL)
                fDeviceModule->uninit_device(fDeviceData);

        fDeviceModule = NULL;
        fDeviceData = NULL;

        put_module(ModuleName());

        fNode->UninitDriver();
}


//      #pragma mark - device_node


/*!     Allocate device node info structure;
        initially, ref_count is one to make sure node won't get destroyed by mistake
*/
device_node::device_node(const char* moduleName, const device_attr* attrs,
        const io_resource* resources)
{
        fModuleName = strdup(moduleName);
        if (fModuleName == NULL)
                return;

        fParent = NULL;
        fRefCount = 1;
        fInitialized = 0;
        fRegistered = false;
        fFlags = 0;
        fSupportsParent = 0.0;
        fLastUpdateCycle = 0;
        fDriver = NULL;
        fDriverData = NULL;

        // copy attributes

        while (attrs != NULL && attrs->name != NULL) {
                device_attr_private* attr
                        = new(std::nothrow) device_attr_private(*attrs);
                if (attr == NULL)
                        break;

                fAttributes.Add(attr);
                attrs++;
        }

        get_attr_uint32(this, B_DEVICE_FLAGS, &fFlags, false);
        fFlags &= NODE_FLAG_PUBLIC_MASK;
}


device_node::~device_node()
{
        TRACE(("delete node %p\n", this));
        ASSERT(DriverModule() == NULL);

        if (Parent() != NULL) {
                if ((fFlags & NODE_FLAG_OBSOLETE_DRIVER) != 0) {
                        // This driver has been obsoleted; another driver has been waiting
                        // for us - make it available
                        Parent()->_ReleaseWaiting();
                }
                Parent()->RemoveChild(this);
        }

        // Delete children
        NodeList::Iterator nodeIterator = fChildren.GetIterator();
        while (nodeIterator.HasNext()) {
                device_node* child = nodeIterator.Next();
                nodeIterator.Remove();
                delete child;
        }

        // Delete devices
        DeviceList::Iterator deviceIterator = fDevices.GetIterator();
        while (deviceIterator.HasNext()) {
                Device* device = deviceIterator.Next();
                deviceIterator.Remove();
                // TODO: unpublish!
                delete device;
        }

        // Delete attributes
        AttributeList::Iterator attrIterator = fAttributes.GetIterator();
        while (attrIterator.HasNext()) {
                device_attr_private* attr = attrIterator.Next();
                attrIterator.Remove();
                delete attr;
        }

        free((char*)fModuleName);
}


status_t
device_node::InitCheck() const
{
        return fModuleName != NULL ? B_OK : B_NO_MEMORY;
}


status_t
device_node::InitDriver()
{
        if (fInitialized++ > 0) {
                if (Parent() != NULL) {
                        Parent()->InitDriver();
                                // acquire another reference to our parent as well
                }
                Acquire();
                return B_OK;
        }

        status_t status = get_module(ModuleName(), (module_info**)&fDriver);
        if (status == B_OK && Parent() != NULL) {
                // our parent always has to be initialized
                status = Parent()->InitDriver();
        }
        if (status < B_OK) {
                fInitialized--;
                return status;
        }

        if (fDriver->init_driver != NULL)
                status = fDriver->init_driver(this, &fDriverData);

        if (status < B_OK) {
                if (Parent() != NULL)
                        Parent()->UninitDriver();
                fInitialized--;

                put_module(ModuleName());
                fDriver = NULL;
                fDriverData = NULL;
                return status;
        }

        Acquire();
        return B_OK;
}


bool
device_node::UninitDriver()
{
        if (fInitialized-- > 1) {
                if (Parent() != NULL)
                        Parent()->UninitDriver();
                Release();
                return false;
        }

        TRACE(("uninit driver for node %p\n", this));

        if (fDriver->uninit_driver != NULL)
                fDriver->uninit_driver(fDriverData);

        fDriver = NULL;
        fDriverData = NULL;

        put_module(ModuleName());

        if (Parent() != NULL)
                Parent()->UninitDriver();
        Release();

        return true;
}


void
device_node::AddChild(device_node* node)
{
        // we must not be destroyed     as long as we have children
        Acquire();
        node->fParent = this;
        fChildren.Add(node);
}


void
device_node::RemoveChild(device_node* node)
{
        node->fParent = NULL;
        fChildren.Remove(node);
        Release();
}


/*!     Registers this node, and all of its children that have to be registered.
        Also initializes the driver and keeps it that way on return in case
        it returns successfully.
*/
status_t
device_node::Register(device_node* parent)
{
        // make it public
        if (parent != NULL)
                parent->AddChild(this);
        else
                sRootNode = this;

        status_t status = InitDriver();
        if (status != B_OK)
                return status;

        if ((fFlags & B_KEEP_DRIVER_LOADED) != 0) {
                // We keep this driver loaded by having it always initialized
                InitDriver();
        }

        fFlags |= NODE_FLAG_REGISTER_INITIALIZED;
                // We don't uninitialize the driver - this is done by the caller
                // in order to save reinitializing during driver loading.

        uint32 registered;
        status = _RegisterFixed(registered);
        if (status != B_OK) {
                UninitUnusedDriver();
                return status;
        }
        if (registered > 0) {
                fRegistered = true;
                return B_OK;
        }

        // Register the children the driver wants

        if (DriverModule()->register_child_devices != NULL) {
                status = DriverModule()->register_child_devices(this);
                if (status != B_OK) {
                        UninitUnusedDriver();
                        return status;
                }

                if (!fChildren.IsEmpty()) {
                        fRegistered = true;
                        return B_OK;
                }
        }

        // Register all possible child device nodes

        status = _RegisterDynamic();
        if (status == B_OK)
                fRegistered = true;
        else
                UninitUnusedDriver();

        return status;
}


/*!     Registers any children that are identified via the B_DRIVER_FIXED_CHILD
        attribute.
        If any of these children cannot be registered, this call will fail (we
        don't remove children we already registered up to this point in this case).
*/
status_t
device_node::_RegisterFixed(uint32& registered)
{
        AttributeList::Iterator iterator = fAttributes.GetIterator();
        registered = 0;

        while (iterator.HasNext()) {
                device_attr_private* attr = iterator.Next();
                if (strcmp(attr->name, B_DEVICE_FIXED_CHILD))
                        continue;

                driver_module_info* driver;
                status_t status = get_module(attr->value.string,
                        (module_info**)&driver);
                if (status != B_OK)
                        return status;

                if (driver->register_device != NULL) {
                        status = driver->register_device(this);
                        if (status == B_OK)
                                registered++;
                }

                put_module(attr->value.string);

                if (status != B_OK)
                        return status;
        }

        return B_OK;
}


status_t
device_node::_AddPath(Stack<KPath*>& stack, const char* basePath,
        const char* subPath)
{
        KPath* path = new(std::nothrow) KPath;
        if (path == NULL)
                return B_NO_MEMORY;

        status_t status = path->SetTo(basePath);
        if (status == B_OK && subPath != NULL && subPath[0])
                status = path->Append(subPath);
        if (status == B_OK)
                status = stack.Push(path);

        if (status != B_OK)
                delete path;

        return status;
}


status_t
device_node::_GetNextDriverPath(void*& cookie, KPath& _path)
{
        Stack<KPath*>* stack = NULL;

        if (cookie == NULL) {
                // find all paths and add them
                stack = new(std::nothrow) Stack<KPath*>();
                if (stack == NULL)
                        return B_NO_MEMORY;

                StackDeleter<KPath*> stackDeleter(stack);
                uint16 type = 0;
                uint16 subType = 0;
                uint16 interface = 0;
                get_attr_uint16(this, B_DEVICE_TYPE, &type, false);
                get_attr_uint16(this, B_DEVICE_SUB_TYPE, &subType, false);
                get_attr_uint16(this, B_DEVICE_INTERFACE, &interface, false);

                // TODO: maybe make this extendible via settings file?
                switch (type) {
                        case PCI_mass_storage:
                                switch (subType) {
                                        case PCI_scsi:
                                                _AddPath(*stack, "busses", "scsi");
                                                break;
                                        case PCI_ide:
                                                _AddPath(*stack, "busses", "ide");
                                                break;
                                        case PCI_sata:
                                                _AddPath(*stack, "busses", "sata");
                                                break;
                                        default:
                                                _AddPath(*stack, "busses", "disk");
                                                break;
                                }
                                break;
                        case PCI_serial_bus:
                                switch (subType) {
                                        case PCI_firewire:
                                                _AddPath(*stack, "busses", "firewire");
                                                break;
                                        case PCI_usb:
                                                _AddPath(*stack, "busses", "usb");
                                                break;
                                        default:
                                                _AddPath(*stack, "busses");
                                                break;
                                }
                                break;
                        case PCI_network:
                                _AddPath(*stack, "drivers", "net");
                                break;
                        case PCI_display:
                                _AddPath(*stack, "drivers", "graphics");
                                break;
                        case PCI_multimedia:
                                switch (subType) {
                                        case PCI_audio:
                                        case PCI_hd_audio:
                                                _AddPath(*stack, "drivers", "audio");
                                                break;
                                        case PCI_video:
                                                _AddPath(*stack, "drivers", "video");
                                                break;
                                        default:
                                                _AddPath(*stack, "drivers");
                                                break;
                                }
                                break;
                        default:
                                if (sRootNode == this) {
                                        _AddPath(*stack, "busses/pci");
                                        _AddPath(*stack, "bus_managers");
                                } else
                                        _AddPath(*stack, "drivers");
                                break;
                }

                stackDeleter.Detach();

                cookie = (void*)stack;
        } else
                stack = static_cast<Stack<KPath*>*>(cookie);

        KPath* path;
        if (stack->Pop(&path)) {
                _path.Adopt(*path);
                delete path;
                return B_OK;
        }

        delete stack;
        return B_ENTRY_NOT_FOUND;
}


status_t
device_node::_GetNextDriver(void* list, driver_module_info*& driver)
{
        while (true) {
                char name[B_FILE_NAME_LENGTH];
                size_t nameLength = sizeof(name);

                status_t status = read_next_module_name(list, name, &nameLength);
                if (status != B_OK)
                        return status;

                if (!strcmp(fModuleName, name))
                        continue;

                if (get_module(name, (module_info**)&driver) != B_OK)
                        continue;

                if (driver->supports_device == NULL
                        || driver->register_device == NULL) {
                        put_module(name);
                        continue;
                }

                return B_OK;
        }
}


status_t
device_node::_FindBestDriver(const char* path, driver_module_info*& bestDriver,
        float& bestSupport, device_node* previous)
{
        if (bestDriver == NULL)
                bestSupport = previous != NULL ? previous->fSupportsParent : 0.0f;

        void* list = open_module_list_etc(path, "driver_v1");
        driver_module_info* driver;
        while (_GetNextDriver(list, driver) == B_OK) {
                if (previous != NULL && driver == previous->DriverModule()) {
                        put_module(driver->info.name);
                        continue;
                }

                float support = driver->supports_device(this);
                if (support > bestSupport) {
                        if (bestDriver != NULL)
                                put_module(bestDriver->info.name);

                        bestDriver = driver;
                        bestSupport = support;
                        continue;
                                // keep reference to best module around
                }

                put_module(driver->info.name);
        }
        close_module_list(list);

        return bestDriver != NULL ? B_OK : B_ENTRY_NOT_FOUND;
}


status_t
device_node::_RegisterPath(const char* path)
{
        void* list = open_module_list_etc(path, "driver_v1");
        driver_module_info* driver;
        uint32 count = 0;

        while (_GetNextDriver(list, driver) == B_OK) {
                float support = driver->supports_device(this);
                if (support > 0.0) {
                        TRACE(("  register module \"%s\", support %f\n", driver->info.name,
                                support));
                        if (driver->register_device(this) == B_OK)
                                count++;
                }

                put_module(driver->info.name);
        }
        close_module_list(list);

        return count > 0 ? B_OK : B_ENTRY_NOT_FOUND;
}


bool
device_node::_AlwaysRegisterDynamic()
{
        uint16 type = 0;
        uint16 subType = 0;
        get_attr_uint16(this, B_DEVICE_TYPE, &type, false);
        get_attr_uint16(this, B_DEVICE_SUB_TYPE, &subType, false);

        return type == PCI_serial_bus || type == PCI_bridge;
                // TODO: we may want to be a bit more specific in the future
}


status_t
device_node::_RegisterDynamic(device_node* previous)
{
        // If this is our initial registration, we honour the B_FIND_CHILD_ON_DEMAND
        // requirements
        if (!fRegistered && (fFlags & B_FIND_CHILD_ON_DEMAND) != 0
                && !_AlwaysRegisterDynamic())
                return B_OK;

        KPath path;

        if ((fFlags & B_FIND_MULTIPLE_CHILDREN) == 0) {
                // find the one driver
                driver_module_info* bestDriver = NULL;
                float bestSupport = 0.0;
                void* cookie = NULL;

                while (_GetNextDriverPath(cookie, path) == B_OK) {
                        _FindBestDriver(path.Path(), bestDriver, bestSupport, previous);
                }

                if (bestDriver != NULL) {
                        TRACE(("  register best module \"%s\", support %f\n",
                                bestDriver->info.name, bestSupport));
                        if (bestDriver->register_device(this) == B_OK) {
                                // There can only be one node of this driver
                                // (usually only one at all, but there might be a new driver
                                // "waiting" for its turn)
                                device_node* child = FindChild(bestDriver->info.name);
                                if (child != NULL) {
                                        child->fSupportsParent = bestSupport;
                                        if (previous != NULL) {
                                                previous->fFlags |= NODE_FLAG_OBSOLETE_DRIVER;
                                                previous->Release();
                                                child->fFlags |= NODE_FLAG_WAITING_FOR_DRIVER;
                                        }
                                }
                                // TODO: if this fails, we could try the second best driver,
                                // and so on...
                        }
                        put_module(bestDriver->info.name);
                }
        } else {
                // register all drivers that match
                void* cookie = NULL;
                while (_GetNextDriverPath(cookie, path) == B_OK) {
                        _RegisterPath(path.Path());
                }
        }

        return B_OK;
}


void
device_node::_ReleaseWaiting()
{
        NodeList::Iterator iterator = fChildren.GetIterator();
        while (iterator.HasNext()) {
                device_node* child = iterator.Next();

                child->fFlags &= ~NODE_FLAG_WAITING_FOR_DRIVER;
        }
}


status_t
device_node::_RemoveChildren()
{
        NodeList::Iterator iterator = fChildren.GetIterator();
        while (iterator.HasNext()) {
                device_node* child = iterator.Next();
                child->Release();
        }

        return fChildren.IsEmpty() ? B_OK : B_BUSY;
}


device_node*
device_node::_FindCurrentChild()
{
        NodeList::Iterator iterator = fChildren.GetIterator();
        while (iterator.HasNext()) {
                device_node* child = iterator.Next();

                if ((child->Flags() & NODE_FLAG_WAITING_FOR_DRIVER) == 0)
                        return child;
        }

        return NULL;
}


status_t
device_node::Probe(const char* devicePath, uint32 updateCycle)
{
        if ((fFlags & NODE_FLAG_DEVICE_REMOVED) != 0
                || updateCycle == fLastUpdateCycle)
                return B_OK;

        status_t status = InitDriver();
        if (status < B_OK)
                return status;

        MethodDeleter<device_node, bool> uninit(this,
                &device_node::UninitDriver);

        uint16 type = 0;
        uint16 subType = 0;
        if (get_attr_uint16(this, B_DEVICE_TYPE, &type, false) == B_OK
                && get_attr_uint16(this, B_DEVICE_SUB_TYPE, &subType, false)
                        == B_OK) {
                // Check if this node matches the device path
                // TODO: maybe make this extendible via settings file?
                bool matches = false;
                if (!strcmp(devicePath, "disk")) {
                        matches = type == PCI_mass_storage;
                } else if (!strcmp(devicePath, "audio")) {
                        matches = type == PCI_multimedia
                                && (subType == PCI_audio || subType == PCI_hd_audio);
                } else if (!strcmp(devicePath, "net")) {
                        matches = type == PCI_network;
                } else if (!strcmp(devicePath, "graphics")) {
                        matches = type == PCI_display;
                } else if (!strcmp(devicePath, "video")) {
                        matches = type == PCI_multimedia && subType == PCI_video;
                }

                if (matches) {
                        device_node* previous = NULL;

                        fLastUpdateCycle = updateCycle;
                                // This node will be probed in this update cycle

                        if (!fChildren.IsEmpty()
                                && (fFlags & B_FIND_MULTIPLE_CHILDREN) == 0) {
                                // We already have a driver that claims this node; remove all
                                // (unused) nodes, and evaluate it again
                                _RemoveChildren();

                                previous = _FindCurrentChild();
                                if (previous != NULL) {
                                        // This driver is still active - give it back the reference
                                        // that was stolen by _RemoveChildren() - _RegisterDynamic()
                                        // will release it, if it really isn't needed anymore
                                        previous->Acquire();
                                }
                        }
                        return _RegisterDynamic(previous);
                }

                return B_OK;
        }

        NodeList::Iterator iterator = fChildren.GetIterator();
        while (iterator.HasNext()) {
                device_node* child = iterator.Next();

                status = child->Probe(devicePath, updateCycle);
                if (status != B_OK)
                        return status;
        }

        return B_OK;
}


/*!     Uninitializes all temporary references to the driver. The registration
        process keeps the driver initialized to optimize the startup procedure;
        this function gives this reference away again.
*/
void
device_node::UninitUnusedDriver()
{
        // First, we need to go to the leaf, and go back from there

        NodeList::Iterator iterator = fChildren.GetIterator();
        while (iterator.HasNext()) {
                device_node* child = iterator.Next();

                child->UninitUnusedDriver();
        }

        if (!IsInitialized()
                || (fFlags & NODE_FLAG_REGISTER_INITIALIZED) == 0)
                return;

        fFlags &= ~NODE_FLAG_REGISTER_INITIALIZED;

        UninitDriver();
}


/*!     Calls device_removed() on this node and all of its children - starting
        with the deepest and last child.
        It will also remove the one reference that every node gets on its creation.
*/
void
device_node::DeviceRemoved()
{
        // notify children
        NodeList::ConstIterator iterator = Children().GetIterator();
        while (iterator.HasNext()) {
                device_node* child = iterator.Next();

                child->DeviceRemoved();
        }

        // notify devices
        DeviceList::ConstIterator deviceIterator = Devices().GetIterator();
        while (deviceIterator.HasNext()) {
                Device* device = deviceIterator.Next();

                if (device->DeviceModule() != NULL
                        && device->DeviceModule()->device_removed != NULL)
                        device->DeviceModule()->device_removed(device->DeviceData());
        }

        fFlags |= NODE_FLAG_DEVICE_REMOVED;

        if (IsInitialized() && DriverModule()->device_removed != NULL)
                DriverModule()->device_removed(this);

        if ((fFlags & B_KEEP_DRIVER_LOADED) != 0) {
                // There is no point in keeping this driver loaded when its device
                // is gone
                UninitDriver();
        }

        UninitUnusedDriver();
        Release();
}


void
device_node::Acquire()
{
        atomic_add(&fRefCount, 1);
}


bool
device_node::Release()
{
        if (atomic_add(&fRefCount, -1) > 1)
                return false;

        delete this;
        return true;
}


void
device_node::AddDevice(Device* device)
{
        fDevices.Add(device);
}


void
device_node::RemoveDevice(Device* device)
{
        fDevices.Remove(device);
}


int
device_node::CompareTo(const device_attr* attributes) const
{
        if (attributes == NULL)
                return -1;

        for (; attributes->name != NULL; attributes++) {
                // find corresponding attribute
                AttributeList::ConstIterator iterator = Attributes().GetIterator();
                device_attr_private* attr = NULL;
                while (iterator.HasNext()) {
                        attr = iterator.Next();

                        if (!strcmp(attr->name, attributes->name))
                                break;
                }
                if (!iterator.HasNext())
                        return -1;

                int compare = device_attr_private::Compare(attr, attributes);
                if (compare != 0)
                        return compare;
        }

        return 0;
}


device_node*
device_node::FindChild(const device_attr* attributes) const
{
        if (attributes == NULL)
                return NULL;

        NodeList::ConstIterator iterator = Children().GetIterator();
        while (iterator.HasNext()) {
                device_node* child = iterator.Next();

                // ignore nodes that are pending to be removed
                if ((child->Flags() & NODE_FLAG_DEVICE_REMOVED) == 0
                        && !child->CompareTo(attributes))
                        return child;
        }

        return NULL;
}


device_node*
device_node::FindChild(const char* moduleName) const
{
        if (moduleName == NULL)
                return NULL;

        NodeList::ConstIterator iterator = Children().GetIterator();
        while (iterator.HasNext()) {
                device_node* child = iterator.Next();

                if (!strcmp(child->ModuleName(), moduleName))
                        return child;
        }

        return NULL;
}


void
device_node::Dump(int32 level = 0)
{
        put_level(level);
        dprintf("(%ld) @%p \"%s\" (ref %ld, init %ld)\n", level, this, ModuleName(),
                fRefCount, fInitialized);

        AttributeList::Iterator attribute = Attributes().GetIterator();
        while (attribute.HasNext()) {
                dump_attribute(attribute.Next(), level);
        }

        NodeList::ConstIterator iterator = Children().GetIterator();
        while (iterator.HasNext()) {
                iterator.Next()->Dump(level + 1);
        }
}


//      #pragma mark - root node


static void
init_root_node(void)
{
        device_attr attrs[] = {
                {B_DEVICE_PRETTY_NAME, B_STRING_TYPE, {string: "Devices Root"}},
                {B_DEVICE_BUS, B_STRING_TYPE, {string: "root"}},
                {B_DEVICE_FLAGS, B_UINT32_TYPE,
                        {ui32: B_FIND_MULTIPLE_CHILDREN | B_KEEP_DRIVER_LOADED }},
                {NULL}
        };

        if (register_node(NULL, DEVICE_MANAGER_ROOT_NAME, attrs, NULL, NULL)
                        != B_OK) {
                dprintf("Cannot register Devices Root Node\n");
        }
}


static driver_module_info sDeviceRootModule = {
        {
                DEVICE_MANAGER_ROOT_NAME,
                0,
                NULL,
        },
        NULL
};


//      #pragma mark -


int
main(int argc, char** argv)
{
        _add_builtin_module((module_info*)&sDeviceManagerModule);
        _add_builtin_module((module_info*)&sDeviceRootModule);

        // bus
        _add_builtin_module((module_info*)&gBusModuleInfo);
        _add_builtin_module((module_info*)&gBusDriverModuleInfo);

        // sample driver
        _add_builtin_module((module_info*)&gDriverModuleInfo);
        _add_builtin_module((module_info*)&gDeviceModuleInfo);

        // generic video driver
        _add_builtin_module((module_info*)&gGenericVideoDriverModuleInfo);
        _add_builtin_module((module_info*)&gGenericVideoDeviceModuleInfo);

        gDeviceManager = &sDeviceManagerModule;

        status_t status = _get_builtin_dependencies();
        if (status < B_OK) {
                fprintf(stderr, "device_manager: Could not initialize modules: %s\n",
                        strerror(status));
                return 1;
        }

        recursive_lock_init(&sLock, "device manager");

        init_root_node();
        sRootNode->Dump();

        probe_path("net");
        probe_path("graphics");

        void* netHandle = open_path("net/sample/0");

        uninit_unused();

        puts("remove net driver");
        device_node* busNode = sRootNode->FindChild(BUS_MODULE_NAME);
        bus_trigger_device_removed(busNode);

        close_path(netHandle);
                // the net nodes must be removed with this call

        void* graphicsHandle = open_path("graphics/generic/0");

        // add specific video driver - ie. simulate installing it
        _add_builtin_module((module_info*)&gSpecificVideoDriverModuleInfo);
        _add_builtin_module((module_info*)&gSpecificVideoDeviceModuleInfo);
        sDriverUpdateCycle++;
        probe_path("graphics");

        open_path("graphics/specific/0");
                // this will fail

        close_path(graphicsHandle);
                // the graphics drivers must be switched with this call

        graphicsHandle = open_path("graphics/specific/0");
        close_path(graphicsHandle);

        uninit_unused();

        recursive_lock_destroy(&sLock);
        return 0;
}