media/libmediaplayerservice/MediaPlayerService.cpp

/*
**
** Copyright 2008, The Android Open Source Project
**
** Licensed under the Apache License, Version 2.0 (the "License");
** you may not use this file except in compliance with the License.
** You may obtain a copy of the License at
**
**     http://www.apache.org/licenses/LICENSE-2.0
**
** Unless required by applicable law or agreed to in writing, software
** distributed under the License is distributed on an "AS IS" BASIS,
** WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
** See the License for the specific language governing permissions and
** limitations under the License.
*/

// Proxy for media player implementations

//#define LOG_NDEBUG 0
#define LOG_TAG "MediaPlayerService"
#include <utils/Log.h>

#include <sys/types.h>
#include <sys/stat.h>
#include <dirent.h>
#include <unistd.h>

#include <string.h>

#include <cutils/atomic.h>
#include <cutils/properties.h> // for property_get

#include <utils/misc.h>

#include <android_runtime/ActivityManager.h>

#include <binder/IPCThreadState.h>
#include <binder/IServiceManager.h>
#include <binder/MemoryHeapBase.h>
#include <binder/MemoryBase.h>
#include <utils/Errors.h>  // for status_t
#include <utils/String8.h>
#include <utils/SystemClock.h>
#include <utils/Vector.h>
#include <cutils/properties.h>

#include <media/MediaPlayerInterface.h>
#include <media/mediarecorder.h>
#include <media/MediaMetadataRetrieverInterface.h>
#include <media/Metadata.h>
#include <media/AudioTrack.h>

#include "MediaRecorderClient.h"
#include "MediaPlayerService.h"
#include "MetadataRetrieverClient.h"

#include "MidiFile.h"
#include "VorbisPlayer.h"
#include <media/PVPlayer.h>
#include "TestPlayerStub.h"
#include "StagefrightPlayer.h"

#include <OMX.h>

/* desktop Linux needs a little help with gettid() */
#if defined(HAVE_GETTID) && !defined(HAVE_ANDROID_OS)
#define __KERNEL__
# include <linux/unistd.h>
#ifdef _syscall0
_syscall0(pid_t,gettid)
#else
pid_t gettid() { return syscall(__NR_gettid);}
#endif
#undef __KERNEL__
#endif

namespace {
using android::media::Metadata;
using android::status_t;
using android::OK;
using android::BAD_VALUE;
using android::NOT_ENOUGH_DATA;
using android::Parcel;

// Max number of entries in the filter.
const int kMaxFilterSize = 64;  // I pulled that out of thin air.

// FIXME: Move all the metadata related function in the Metadata.cpp


// Unmarshall a filter from a Parcel.
// Filter format in a parcel:
//
//  0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
// |                       number of entries (n)                   |
// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
// |                       metadata type 1                         |
// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
// |                       metadata type 2                         |
// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
//  ....
// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
// |                       metadata type n                         |
// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
//
// @param p Parcel that should start with a filter.
// @param[out] filter On exit contains the list of metadata type to be
//                    filtered.
// @param[out] status On exit contains the status code to be returned.
// @return true if the parcel starts with a valid filter.
bool unmarshallFilter(const Parcel& p,
                      Metadata::Filter *filter,
                      status_t *status)
{
    int32_t val;
    if (p.readInt32(&val) != OK)
    {
        LOGE("Failed to read filter's length");
        *status = NOT_ENOUGH_DATA;
        return false;
    }

    if( val > kMaxFilterSize || val < 0)
    {
        LOGE("Invalid filter len %d", val);
        *status = BAD_VALUE;
        return false;
    }

    const size_t num = val;

    filter->clear();
    filter->setCapacity(num);

    size_t size = num * sizeof(Metadata::Type);


    if (p.dataAvail() < size)
    {
        LOGE("Filter too short expected %d but got %d", size, p.dataAvail());
        *status = NOT_ENOUGH_DATA;
        return false;
    }

    const Metadata::Type *data =
            static_cast<const Metadata::Type*>(p.readInplace(size));

    if (NULL == data)
    {
        LOGE("Filter had no data");
        *status = BAD_VALUE;
        return false;
    }

    // TODO: The stl impl of vector would be more efficient here
    // because it degenerates into a memcpy on pod types. Try to
    // replace later or use stl::set.
    for (size_t i = 0; i < num; ++i)
    {
        filter->add(*data);
        ++data;
    }
    *status = OK;
    return true;
}

// @param filter Of metadata type.
// @param val To be searched.
// @return true if a match was found.
bool findMetadata(const Metadata::Filter& filter, const int32_t val)
{
    // Deal with empty and ANY right away
    if (filter.isEmpty()) return false;
    if (filter[0] == Metadata::kAny) return true;

    return filter.indexOf(val) >= 0;
}

}  // anonymous namespace


namespace android {

// TODO: Temp hack until we can register players
typedef struct {
    const char *extension;
    const player_type playertype;
} extmap;
extmap FILE_EXTS [] =  {
        {".mid", SONIVOX_PLAYER},
        {".midi", SONIVOX_PLAYER},
        {".smf", SONIVOX_PLAYER},
        {".xmf", SONIVOX_PLAYER},
        {".imy", SONIVOX_PLAYER},
        {".rtttl", SONIVOX_PLAYER},
        {".rtx", SONIVOX_PLAYER},
        {".ota", SONIVOX_PLAYER},
        {".ogg", VORBIS_PLAYER},
        {".oga", VORBIS_PLAYER},
};

// TODO: Find real cause of Audio/Video delay in PV framework and remove this workaround
/* static */ int MediaPlayerService::AudioOutput::mMinBufferCount = 4;
/* static */ bool MediaPlayerService::AudioOutput::mIsOnEmulator = false;

void MediaPlayerService::instantiate() {
    defaultServiceManager()->addService(
            String16("media.player"), new MediaPlayerService());
}

MediaPlayerService::MediaPlayerService()
{
    LOGV("MediaPlayerService created");
    mNextConnId = 1;
}

MediaPlayerService::~MediaPlayerService()
{
    LOGV("MediaPlayerService destroyed");
}

sp<IMediaRecorder> MediaPlayerService::createMediaRecorder(pid_t pid)
{
#ifndef NO_OPENCORE
    sp<MediaRecorderClient> recorder = new MediaRecorderClient(this, pid);
    wp<MediaRecorderClient> w = recorder;
    Mutex::Autolock lock(mLock);
    mMediaRecorderClients.add(w);
#else
    sp<MediaRecorderClient> recorder = NULL;
#endif
    LOGV("Create new media recorder client from pid %d", pid);
    return recorder;
}

void MediaPlayerService::removeMediaRecorderClient(wp<MediaRecorderClient> client)
{
    Mutex::Autolock lock(mLock);
    mMediaRecorderClients.remove(client);
    LOGV("Delete media recorder client");
}

sp<IMediaMetadataRetriever> MediaPlayerService::createMetadataRetriever(pid_t pid)
{
    sp<MetadataRetrieverClient> retriever = new MetadataRetrieverClient(pid);
    LOGV("Create new media retriever from pid %d", pid);
    return retriever;
}

sp<IMediaPlayer> MediaPlayerService::create(pid_t pid, const sp<IMediaPlayerClient>& client, const char* url)
{
    int32_t connId = android_atomic_inc(&mNextConnId);
    sp<Client> c = new Client(this, pid, connId, client);
    LOGV("Create new client(%d) from pid %d, url=%s, connId=%d", connId, pid, url, connId);
    if (NO_ERROR != c->setDataSource(url))
    {
        c.clear();
        return c;
    }
    wp<Client> w = c;
    Mutex::Autolock lock(mLock);
    mClients.add(w);
    return c;
}

sp<IMediaPlayer> MediaPlayerService::create(pid_t pid, const sp<IMediaPlayerClient>& client,
        int fd, int64_t offset, int64_t length)
{
    int32_t connId = android_atomic_inc(&mNextConnId);
    sp<Client> c = new Client(this, pid, connId, client);
    LOGV("Create new client(%d) from pid %d, fd=%d, offset=%lld, length=%lld",
            connId, pid, fd, offset, length);
    if (NO_ERROR != c->setDataSource(fd, offset, length)) {
        c.clear();
    } else {
        wp<Client> w = c;
        Mutex::Autolock lock(mLock);
        mClients.add(w);
    }
    ::close(fd);
    return c;
}

sp<IOMX> MediaPlayerService::getOMX() {
    Mutex::Autolock autoLock(mLock);

    if (mOMX.get() == NULL) {
        mOMX = new OMX;
    }

    return mOMX;
}

status_t MediaPlayerService::AudioCache::dump(int fd, const Vector<String16>& args) const
{
    const size_t SIZE = 256;
    char buffer[SIZE];
    String8 result;

    result.append(" AudioCache\n");
    if (mHeap != 0) {
        snprintf(buffer, 255, "  heap base(%p), size(%d), flags(%d), device(%s)\n",
                mHeap->getBase(), mHeap->getSize(), mHeap->getFlags(), mHeap->getDevice());
        result.append(buffer);
    }
    snprintf(buffer, 255, "  msec per frame(%f), channel count(%d), format(%d), frame count(%ld)\n",
            mMsecsPerFrame, mChannelCount, mFormat, mFrameCount);
    result.append(buffer);
    snprintf(buffer, 255, "  sample rate(%d), size(%d), error(%d), command complete(%s)\n",
            mSampleRate, mSize, mError, mCommandComplete?"true":"false");
    result.append(buffer);
    ::write(fd, result.string(), result.size());
    return NO_ERROR;
}

status_t MediaPlayerService::AudioOutput::dump(int fd, const Vector<String16>& args) const
{
    const size_t SIZE = 256;
    char buffer[SIZE];
    String8 result;

    result.append(" AudioOutput\n");
    snprintf(buffer, 255, "  stream type(%d), left - right volume(%f, %f)\n",
            mStreamType, mLeftVolume, mRightVolume);
    result.append(buffer);
    snprintf(buffer, 255, "  msec per frame(%f), latency (%d)\n",
            mMsecsPerFrame, mLatency);
    result.append(buffer);
    ::write(fd, result.string(), result.size());
    if (mTrack != 0) {
        mTrack->dump(fd, args);
    }
    return NO_ERROR;
}

status_t MediaPlayerService::Client::dump(int fd, const Vector<String16>& args) const
{
    const size_t SIZE = 256;
    char buffer[SIZE];
    String8 result;
    result.append(" Client\n");
    snprintf(buffer, 255, "  pid(%d), connId(%d), status(%d), looping(%s)\n",
            mPid, mConnId, mStatus, mLoop?"true": "false");
    result.append(buffer);
    write(fd, result.string(), result.size());
    if (mAudioOutput != 0) {
        mAudioOutput->dump(fd, args);
    }
    write(fd, "\n", 1);
    return NO_ERROR;
}

static int myTid() {
#ifdef HAVE_GETTID
    return gettid();
#else
    return getpid();
#endif
}

#if defined(__arm__)
extern "C" void get_malloc_leak_info(uint8_t** info, size_t* overallSize,
        size_t* infoSize, size_t* totalMemory, size_t* backtraceSize);
extern "C" void free_malloc_leak_info(uint8_t* info);

// Use the String-class below instead of String8 to allocate all memory
// beforehand and not reenter the heap while we are examining it...
struct MyString8 {
    static const size_t MAX_SIZE = 256 * 1024;

    MyString8()
        : mPtr((char *)malloc(MAX_SIZE)) {
        *mPtr = '\0';
    }

    ~MyString8() {
        free(mPtr);
    }

    void append(const char *s) {
        strcat(mPtr, s);
    }

    const char *string() const {
        return mPtr;
    }

    size_t size() const {
        return strlen(mPtr);
    }

private:
    char *mPtr;

    MyString8(const MyString8 &);
    MyString8 &operator=(const MyString8 &);
};

void memStatus(int fd, const Vector<String16>& args)
{
    const size_t SIZE = 256;
    char buffer[SIZE];
    MyString8 result;

    typedef struct {
        size_t size;
        size_t dups;
        intptr_t * backtrace;
    } AllocEntry;

    uint8_t *info = NULL;
    size_t overallSize = 0;
    size_t infoSize = 0;
    size_t totalMemory = 0;
    size_t backtraceSize = 0;

    get_malloc_leak_info(&info, &overallSize, &infoSize, &totalMemory, &backtraceSize);
    if (info) {
        uint8_t *ptr = info;
        size_t count = overallSize / infoSize;

        snprintf(buffer, SIZE, " Allocation count %i\n", count);
        result.append(buffer);

        AllocEntry * entries = new AllocEntry[count];

        for (size_t i = 0; i < count; i++) {
            // Each entry should be size_t, size_t, intptr_t[backtraceSize]
            AllocEntry *e = &entries[i];

            e->size = *reinterpret_cast<size_t *>(ptr);
            ptr += sizeof(size_t);

            e->dups = *reinterpret_cast<size_t *>(ptr);
            ptr += sizeof(size_t);

            e->backtrace = reinterpret_cast<intptr_t *>(ptr);
            ptr += sizeof(intptr_t) * backtraceSize;
        }

        // Now we need to sort the entries.  They come sorted by size but
        // not by stack trace which causes problems using diff.
        bool moved;
        do {
            moved = false;
            for (size_t i = 0; i < (count - 1); i++) {
                AllocEntry *e1 = &entries[i];
                AllocEntry *e2 = &entries[i+1];

                bool swap = e1->size < e2->size;
                if (e1->size == e2->size) {
                    for(size_t j = 0; j < backtraceSize; j++) {
                        if (e1->backtrace[j] == e2->backtrace[j]) {
                            continue;
                        }
                        swap = e1->backtrace[j] < e2->backtrace[j];
                        break;
                    }
                }
                if (swap) {
                    AllocEntry t = entries[i];
                    entries[i] = entries[i+1];
                    entries[i+1] = t;
                    moved = true;
                }
            }
        } while (moved);

        for (size_t i = 0; i < count; i++) {
            AllocEntry *e = &entries[i];

            snprintf(buffer, SIZE, "size %8i, dup %4i", e->size, e->dups);
            result.append(buffer);
            for (size_t ct = 0; (ct < backtraceSize) && e->backtrace[ct]; ct++) {
                if (ct) {
                    result.append(", ");
                }
                snprintf(buffer, SIZE, "0x%08x", e->backtrace[ct]);
                result.append(buffer);
            }
            result.append("\n");
        }

        delete[] entries;
        free_malloc_leak_info(info);
    }

    write(fd, result.string(), result.size());
}
#endif

status_t MediaPlayerService::dump(int fd, const Vector<String16>& args)
{
    const size_t SIZE = 256;
    char buffer[SIZE];
    String8 result;
    if (checkCallingPermission(String16("android.permission.DUMP")) == false) {
        snprintf(buffer, SIZE, "Permission Denial: "
                "can't dump MediaPlayerService from pid=%d, uid=%d\n",
                IPCThreadState::self()->getCallingPid(),
                IPCThreadState::self()->getCallingUid());
        result.append(buffer);
    } else {
        Mutex::Autolock lock(mLock);
        for (int i = 0, n = mClients.size(); i < n; ++i) {
            sp<Client> c = mClients[i].promote();
            if (c != 0) c->dump(fd, args);
        }
        for (int i = 0, n = mMediaRecorderClients.size(); i < n; ++i) {
            result.append(" MediaRecorderClient\n");
            sp<MediaRecorderClient> c = mMediaRecorderClients[i].promote();
            snprintf(buffer, 255, "  pid(%d)\n\n", c->mPid);
            result.append(buffer);
        }

        result.append(" Files opened and/or mapped:\n");
        snprintf(buffer, SIZE, "/proc/%d/maps", myTid());
        FILE *f = fopen(buffer, "r");
        if (f) {
            while (!feof(f)) {
                fgets(buffer, SIZE, f);
                if (strstr(buffer, " /sdcard/") ||
                    strstr(buffer, " /system/sounds/") ||
                    strstr(buffer, " /system/media/")) {
                    result.append("  ");
                    result.append(buffer);
                }
            }
            fclose(f);
        } else {
            result.append("couldn't open ");
            result.append(buffer);
            result.append("\n");
        }

        snprintf(buffer, SIZE, "/proc/%d/fd", myTid());
        DIR *d = opendir(buffer);
        if (d) {
            struct dirent *ent;
            while((ent = readdir(d)) != NULL) {
                if (strcmp(ent->d_name,".") && strcmp(ent->d_name,"..")) {
                    snprintf(buffer, SIZE, "/proc/%d/fd/%s", myTid(), ent->d_name);
                    struct stat s;
                    if (lstat(buffer, &s) == 0) {
                        if ((s.st_mode & S_IFMT) == S_IFLNK) {
                            char linkto[256];
                            int len = readlink(buffer, linkto, sizeof(linkto));
                            if(len > 0) {
                                if(len > 255) {
                                    linkto[252] = '.';
                                    linkto[253] = '.';
                                    linkto[254] = '.';
                                    linkto[255] = 0;
                                } else {
                                    linkto[len] = 0;
                                }
                                if (strstr(linkto, "/sdcard/") == linkto ||
                                    strstr(linkto, "/system/sounds/") == linkto ||
                                    strstr(linkto, "/system/media/") == linkto) {
                                    result.append("  ");
                                    result.append(buffer);
                                    result.append(" -> ");
                                    result.append(linkto);
                                    result.append("\n");
                                }
                            }
                        } else {
                            result.append("  unexpected type for ");
                            result.append(buffer);
                            result.append("\n");
                        }
                    }
                }
            }
            closedir(d);
        } else {
            result.append("couldn't open ");
            result.append(buffer);
            result.append("\n");
        }

#if defined(__arm__)
        bool dumpMem = false;
        for (size_t i = 0; i < args.size(); i++) {
            if (args[i] == String16("-m")) {
                dumpMem = true;
            }
        }
        if (dumpMem) {
            memStatus(fd, args);
        }
#endif
    }
    write(fd, result.string(), result.size());
    return NO_ERROR;
}

void MediaPlayerService::removeClient(wp<Client> client)
{
    Mutex::Autolock lock(mLock);
    mClients.remove(client);
}

MediaPlayerService::Client::Client(const sp<MediaPlayerService>& service, pid_t pid,
        int32_t connId, const sp<IMediaPlayerClient>& client)
{
    LOGV("Client(%d) constructor", connId);
    mPid = pid;
    mConnId = connId;
    mService = service;
    mClient = client;
    mLoop = false;
    mStatus = NO_INIT;
#if CALLBACK_ANTAGONIZER
    LOGD("create Antagonizer");
    mAntagonizer = new Antagonizer(notify, this);
#endif
}

MediaPlayerService::Client::~Client()
{
    LOGV("Client(%d) destructor pid = %d", mConnId, mPid);
    mAudioOutput.clear();
    wp<Client> client(this);
    disconnect();
    mService->removeClient(client);
}

void MediaPlayerService::Client::disconnect()
{
    LOGV("disconnect(%d) from pid %d", mConnId, mPid);
    // grab local reference and clear main reference to prevent future
    // access to object
    sp<MediaPlayerBase> p;
    {
        Mutex::Autolock l(mLock);
        p = mPlayer;
    }
    mClient.clear();

    mPlayer.clear();

    // clear the notification to prevent callbacks to dead client
    // and reset the player. We assume the player will serialize
    // access to itself if necessary.
    if (p != 0) {
        p->setNotifyCallback(0, 0);
#if CALLBACK_ANTAGONIZER
        LOGD("kill Antagonizer");
        mAntagonizer->kill();
#endif
        p->reset();
    }

    IPCThreadState::self()->flushCommands();
}

static player_type getDefaultPlayerType() {
#if BUILD_WITH_FULL_STAGEFRIGHT
    char value[PROPERTY_VALUE_MAX];
    if (property_get("media.stagefright.enable-player", value, NULL)
        && (!strcmp(value, "1") || !strcasecmp(value, "true"))) {
        return STAGEFRIGHT_PLAYER;
    }
#endif

    return PV_PLAYER;
}

player_type getPlayerType(int fd, int64_t offset, int64_t length)
{
    char buf[20];
    lseek(fd, offset, SEEK_SET);
    read(fd, buf, sizeof(buf));
    lseek(fd, offset, SEEK_SET);

    long ident = *((long*)buf);

    // Ogg vorbis?
    if (ident == 0x5367674f) // 'OggS'
        return VORBIS_PLAYER;

    // Some kind of MIDI?
    EAS_DATA_HANDLE easdata;
    if (EAS_Init(&easdata) == EAS_SUCCESS) {
        EAS_FILE locator;
        locator.path = NULL;
        locator.fd = fd;
        locator.offset = offset;
        locator.length = length;
        EAS_HANDLE  eashandle;
        if (EAS_OpenFile(easdata, &locator, &eashandle) == EAS_SUCCESS) {
            EAS_CloseFile(easdata, eashandle);
            EAS_Shutdown(easdata);
            return SONIVOX_PLAYER;
        }
        EAS_Shutdown(easdata);
    }

    return getDefaultPlayerType();
}

player_type getPlayerType(const char* url)
{
    if (TestPlayerStub::canBeUsed(url)) {
        return TEST_PLAYER;
    }

    // use MidiFile for MIDI extensions
    int lenURL = strlen(url);
    for (int i = 0; i < NELEM(FILE_EXTS); ++i) {
        int len = strlen(FILE_EXTS[i].extension);
        int start = lenURL - len;
        if (start > 0) {
            if (!strncmp(url + start, FILE_EXTS[i].extension, len)) {
                return FILE_EXTS[i].playertype;
            }
        }
    }

    return getDefaultPlayerType();
}

static sp<MediaPlayerBase> createPlayer(player_type playerType, void* cookie,
        notify_callback_f notifyFunc)
{
    sp<MediaPlayerBase> p;
    switch (playerType) {
#ifndef NO_OPENCORE
        case PV_PLAYER:
            LOGV(" create PVPlayer");
            p = new PVPlayer();
            break;
#endif
        case SONIVOX_PLAYER:
            LOGV(" create MidiFile");
            p = new MidiFile();
            break;
        case VORBIS_PLAYER:
            LOGV(" create VorbisPlayer");
            p = new VorbisPlayer();
            break;
#if BUILD_WITH_FULL_STAGEFRIGHT
        case STAGEFRIGHT_PLAYER:
            LOGV(" create StagefrightPlayer");
            p = new StagefrightPlayer;
            break;
#endif
        case TEST_PLAYER:
            LOGV("Create Test Player stub");
            p = new TestPlayerStub();
            break;
    }
    if (p != NULL) {
        if (p->initCheck() == NO_ERROR) {
            p->setNotifyCallback(cookie, notifyFunc);
        } else {
            p.clear();
        }
    }
    if (p == NULL) {
        LOGE("Failed to create player object");
    }
    return p;
}

sp<MediaPlayerBase> MediaPlayerService::Client::createPlayer(player_type playerType)
{
    // determine if we have the right player type
    sp<MediaPlayerBase> p = mPlayer;
    if ((p != NULL) && (p->playerType() != playerType)) {
        LOGV("delete player");
        p.clear();
    }
    if (p == NULL) {
        p = android::createPlayer(playerType, this, notify);
    }
    return p;
}

status_t MediaPlayerService::Client::setDataSource(const char *url)
{
    LOGV("setDataSource(%s)", url);
    if (url == NULL)
        return UNKNOWN_ERROR;

    if (strncmp(url, "content://", 10) == 0) {
        // get a filedescriptor for the content Uri and
        // pass it to the setDataSource(fd) method

        String16 url16(url);
        int fd = android::openContentProviderFile(url16);
        if (fd < 0)
        {
            LOGE("Couldn't open fd for %s", url);
            return UNKNOWN_ERROR;
        }
        setDataSource(fd, 0, 0x7fffffffffLL); // this sets mStatus
        close(fd);
        return mStatus;
    } else {
        player_type playerType = getPlayerType(url);
        LOGV("player type = %d", playerType);

        // create the right type of player
        sp<MediaPlayerBase> p = createPlayer(playerType);
        if (p == NULL) return NO_INIT;

        if (!p->hardwareOutput()) {
            mAudioOutput = new AudioOutput();
            static_cast<MediaPlayerInterface*>(p.get())->setAudioSink(mAudioOutput);
        }

        // now set data source
        LOGV(" setDataSource");
        mStatus = p->setDataSource(url);
        if (mStatus == NO_ERROR) {
            mPlayer = p;
        } else {
            LOGE("  error: %d", mStatus);
        }
        return mStatus;
    }
}

status_t MediaPlayerService::Client::setDataSource(int fd, int64_t offset, int64_t length)
{
    LOGV("setDataSource fd=%d, offset=%lld, length=%lld", fd, offset, length);
    struct stat sb;
    int ret = fstat(fd, &sb);
    if (ret != 0) {
        LOGE("fstat(%d) failed: %d, %s", fd, ret, strerror(errno));
        return UNKNOWN_ERROR;
    }

    LOGV("st_dev  = %llu", sb.st_dev);
    LOGV("st_mode = %u", sb.st_mode);
    LOGV("st_uid  = %lu", sb.st_uid);
    LOGV("st_gid  = %lu", sb.st_gid);
    LOGV("st_size = %llu", sb.st_size);

    if (offset >= sb.st_size) {
        LOGE("offset error");
        ::close(fd);
        return UNKNOWN_ERROR;
    }
    if (offset + length > sb.st_size) {
        length = sb.st_size - offset;
        LOGV("calculated length = %lld", length);
    }

    player_type playerType = getPlayerType(fd, offset, length);
    LOGV("player type = %d", playerType);

    // create the right type of player
    sp<MediaPlayerBase> p = createPlayer(playerType);
    if (p == NULL) return NO_INIT;

    if (!p->hardwareOutput()) {
        mAudioOutput = new AudioOutput();
        static_cast<MediaPlayerInterface*>(p.get())->setAudioSink(mAudioOutput);
    }

    // now set data source
    mStatus = p->setDataSource(fd, offset, length);
    if (mStatus == NO_ERROR) mPlayer = p;
    return mStatus;
}

status_t MediaPlayerService::Client::setVideoSurface(const sp<ISurface>& surface)
{
    LOGV("[%d] setVideoSurface(%p)", mConnId, surface.get());
    sp<MediaPlayerBase> p = getPlayer();
    if (p == 0) return UNKNOWN_ERROR;
    return p->setVideoSurface(surface);
}

status_t MediaPlayerService::Client::invoke(const Parcel& request,
                                            Parcel *reply)
{
    sp<MediaPlayerBase> p = getPlayer();
    if (p == NULL) return UNKNOWN_ERROR;
    return p->invoke(request, reply);
}

// This call doesn't need to access the native player.
status_t MediaPlayerService::Client::setMetadataFilter(const Parcel& filter)
{
    status_t status;
    media::Metadata::Filter allow, drop;

    if (unmarshallFilter(filter, &allow, &status) &&
        unmarshallFilter(filter, &drop, &status)) {
        Mutex::Autolock lock(mLock);

        mMetadataAllow = allow;
        mMetadataDrop = drop;
    }
    return status;
}

status_t MediaPlayerService::Client::getMetadata(
        bool update_only, bool apply_filter, Parcel *reply)
{
    sp<MediaPlayerBase> player = getPlayer();
    if (player == 0) return UNKNOWN_ERROR;

    status_t status;
    // Placeholder for the return code, updated by the caller.
    reply->writeInt32(-1);

    media::Metadata::Filter ids;

    // We don't block notifications while we fetch the data. We clear
    // mMetadataUpdated first so we don't lose notifications happening
    // during the rest of this call.
    {
        Mutex::Autolock lock(mLock);
        if (update_only) {
            ids = mMetadataUpdated;
        }
        mMetadataUpdated.clear();
    }

    media::Metadata metadata(reply);

    metadata.appendHeader();
    status = player->getMetadata(ids, reply);

    if (status != OK) {
        metadata.resetParcel();
        LOGE("getMetadata failed %d", status);
        return status;
    }

    // FIXME: Implement filtering on the result. Not critical since
    // filtering takes place on the update notifications already. This
    // would be when all the metadata are fetch and a filter is set.

    // Everything is fine, update the metadata length.
    metadata.updateLength();
    return OK;
}

status_t MediaPlayerService::Client::prepareAsync()
{
    LOGV("[%d] prepareAsync", mConnId);
    sp<MediaPlayerBase> p = getPlayer();
    if (p == 0) return UNKNOWN_ERROR;
    status_t ret = p->prepareAsync();
#if CALLBACK_ANTAGONIZER
    LOGD("start Antagonizer");
    if (ret == NO_ERROR) mAntagonizer->start();
#endif
    return ret;
}

status_t MediaPlayerService::Client::start()
{
    LOGV("[%d] start", mConnId);
    sp<MediaPlayerBase> p = getPlayer();
    if (p == 0) return UNKNOWN_ERROR;
    p->setLooping(mLoop);
    return p->start();
}

status_t MediaPlayerService::Client::stop()
{
    LOGV("[%d] stop", mConnId);
    sp<MediaPlayerBase> p = getPlayer();
    if (p == 0) return UNKNOWN_ERROR;
    return p->stop();
}

status_t MediaPlayerService::Client::pause()
{
    LOGV("[%d] pause", mConnId);
    sp<MediaPlayerBase> p = getPlayer();
    if (p == 0) return UNKNOWN_ERROR;
    return p->pause();
}

status_t MediaPlayerService::Client::isPlaying(bool* state)
{
    *state = false;
    sp<MediaPlayerBase> p = getPlayer();
    if (p == 0) return UNKNOWN_ERROR;
    *state = p->isPlaying();
    LOGV("[%d] isPlaying: %d", mConnId, *state);
    return NO_ERROR;
}

status_t MediaPlayerService::Client::getCurrentPosition(int *msec)
{
    LOGV("getCurrentPosition");
    sp<MediaPlayerBase> p = getPlayer();
    if (p == 0) return UNKNOWN_ERROR;
    status_t ret = p->getCurrentPosition(msec);
    if (ret == NO_ERROR) {
        LOGV("[%d] getCurrentPosition = %d", mConnId, *msec);
    } else {
        LOGE("getCurrentPosition returned %d", ret);
    }
    return ret;
}

status_t MediaPlayerService::Client::getDuration(int *msec)
{
    LOGV("getDuration");
    sp<MediaPlayerBase> p = getPlayer();
    if (p == 0) return UNKNOWN_ERROR;
    status_t ret = p->getDuration(msec);
    if (ret == NO_ERROR) {
        LOGV("[%d] getDuration = %d", mConnId, *msec);
    } else {
        LOGE("getDuration returned %d", ret);
    }
    return ret;
}

status_t MediaPlayerService::Client::seekTo(int msec)
{
    LOGV("[%d] seekTo(%d)", mConnId, msec);
    sp<MediaPlayerBase> p = getPlayer();
    if (p == 0) return UNKNOWN_ERROR;
    return p->seekTo(msec);
}

status_t MediaPlayerService::Client::reset()
{
    LOGV("[%d] reset", mConnId);
    sp<MediaPlayerBase> p = getPlayer();
    if (p == 0) return UNKNOWN_ERROR;
    return p->reset();
}

status_t MediaPlayerService::Client::setAudioStreamType(int type)
{
    LOGV("[%d] setAudioStreamType(%d)", mConnId, type);
    // TODO: for hardware output, call player instead
    Mutex::Autolock l(mLock);
    if (mAudioOutput != 0) mAudioOutput->setAudioStreamType(type);
    return NO_ERROR;
}

status_t MediaPlayerService::Client::setLooping(int loop)
{
    LOGV("[%d] setLooping(%d)", mConnId, loop);
    mLoop = loop;
    sp<MediaPlayerBase> p = getPlayer();
    if (p != 0) return p->setLooping(loop);
    return NO_ERROR;
}

status_t MediaPlayerService::Client::setVolume(float leftVolume, float rightVolume)
{
    LOGV("[%d] setVolume(%f, %f)", mConnId, leftVolume, rightVolume);
    // TODO: for hardware output, call player instead
    Mutex::Autolock l(mLock);
    if (mAudioOutput != 0) mAudioOutput->setVolume(leftVolume, rightVolume);
    return NO_ERROR;
}


void MediaPlayerService::Client::notify(void* cookie, int msg, int ext1, int ext2)
{
    Client* client = static_cast<Client*>(cookie);

    if (MEDIA_INFO == msg &&
        MEDIA_INFO_METADATA_UPDATE == ext1) {
        const media::Metadata::Type metadata_type = ext2;

        if(client->shouldDropMetadata(metadata_type)) {
            return;
        }

        // Update the list of metadata that have changed. getMetadata
        // also access mMetadataUpdated and clears it.
        client->addNewMetadataUpdate(metadata_type);
    }
    LOGV("[%d] notify (%p, %d, %d, %d)", client->mConnId, cookie, msg, ext1, ext2);
    client->mClient->notify(msg, ext1, ext2);
}


bool MediaPlayerService::Client::shouldDropMetadata(media::Metadata::Type code) const
{
    Mutex::Autolock lock(mLock);

    if (findMetadata(mMetadataDrop, code)) {
        return true;
    }

    if (mMetadataAllow.isEmpty() || findMetadata(mMetadataAllow, code)) {
        return false;
    } else {
        return true;
    }
}


void MediaPlayerService::Client::addNewMetadataUpdate(media::Metadata::Type metadata_type) {
    Mutex::Autolock lock(mLock);
    if (mMetadataUpdated.indexOf(metadata_type) < 0) {
        mMetadataUpdated.add(metadata_type);
    }
}

#if CALLBACK_ANTAGONIZER
const int Antagonizer::interval = 10000; // 10 msecs

Antagonizer::Antagonizer(notify_callback_f cb, void* client) :
    mExit(false), mActive(false), mClient(client), mCb(cb)
{
    createThread(callbackThread, this);
}

void Antagonizer::kill()
{
    Mutex::Autolock _l(mLock);
    mActive = false;
    mExit = true;
    mCondition.wait(mLock);
}

int Antagonizer::callbackThread(void* user)
{
    LOGD("Antagonizer started");
    Antagonizer* p = reinterpret_cast<Antagonizer*>(user);
    while (!p->mExit) {
        if (p->mActive) {
            LOGV("send event");
            p->mCb(p->mClient, 0, 0, 0);
        }
        usleep(interval);
    }
    Mutex::Autolock _l(p->mLock);
    p->mCondition.signal();
    LOGD("Antagonizer stopped");
    return 0;
}
#endif

static size_t kDefaultHeapSize = 1024 * 1024; // 1MB

sp<IMemory> MediaPlayerService::decode(const char* url, uint32_t *pSampleRate, int* pNumChannels, int* pFormat)
{
    LOGV("decode(%s)", url);
    sp<MemoryBase> mem;
    sp<MediaPlayerBase> player;

    // Protect our precious, precious DRMd ringtones by only allowing
    // decoding of http, but not filesystem paths or content Uris.
    // If the application wants to decode those, it should open a
    // filedescriptor for them and use that.
    if (url != NULL && strncmp(url, "http://", 7) != 0) {
        LOGD("Can't decode %s by path, use filedescriptor instead", url);
        return mem;
    }

    player_type playerType = getPlayerType(url);
    LOGV("player type = %d", playerType);

    // create the right type of player
    sp<AudioCache> cache = new AudioCache(url);
    player = android::createPlayer(playerType, cache.get(), cache->notify);
    if (player == NULL) goto Exit;
    if (player->hardwareOutput()) goto Exit;

    static_cast<MediaPlayerInterface*>(player.get())->setAudioSink(cache);

    // set data source
    if (player->setDataSource(url) != NO_ERROR) goto Exit;

    LOGV("prepare");
    player->prepareAsync();

    LOGV("wait for prepare");
    if (cache->wait() != NO_ERROR) goto Exit;

    LOGV("start");
    player->start();

    LOGV("wait for playback complete");
    if (cache->wait() != NO_ERROR) goto Exit;

    mem = new MemoryBase(cache->getHeap(), 0, cache->size());
    *pSampleRate = cache->sampleRate();
    *pNumChannels = cache->channelCount();
    *pFormat = cache->format();
    LOGV("return memory @ %p, sampleRate=%u, channelCount = %d, format = %d", mem->pointer(), *pSampleRate, *pNumChannels, *pFormat);

Exit:
    if (player != 0) player->reset();
    return mem;
}

sp<IMemory> MediaPlayerService::decode(int fd, int64_t offset, int64_t length, uint32_t *pSampleRate, int* pNumChannels, int* pFormat)
{
    LOGV("decode(%d, %lld, %lld)", fd, offset, length);
    sp<MemoryBase> mem;
    sp<MediaPlayerBase> player;

    player_type playerType = getPlayerType(fd, offset, length);
    LOGV("player type = %d", playerType);

    // create the right type of player
    sp<AudioCache> cache = new AudioCache("decode_fd");
    player = android::createPlayer(playerType, cache.get(), cache->notify);
    if (player == NULL) goto Exit;
    if (player->hardwareOutput()) goto Exit;

    static_cast<MediaPlayerInterface*>(player.get())->setAudioSink(cache);

    // set data source
    if (player->setDataSource(fd, offset, length) != NO_ERROR) goto Exit;

    LOGV("prepare");
    player->prepareAsync();

    LOGV("wait for prepare");
    if (cache->wait() != NO_ERROR) goto Exit;

    LOGV("start");
    player->start();

    LOGV("wait for playback complete");
    if (cache->wait() != NO_ERROR) goto Exit;

    mem = new MemoryBase(cache->getHeap(), 0, cache->size());
    *pSampleRate = cache->sampleRate();
    *pNumChannels = cache->channelCount();
    *pFormat = cache->format();
    LOGV("return memory @ %p, sampleRate=%u, channelCount = %d, format = %d", mem->pointer(), *pSampleRate, *pNumChannels, *pFormat);

Exit:
    if (player != 0) player->reset();
    ::close(fd);
    return mem;
}

/*
 * Avert your eyes, ugly hack ahead.
 * The following is to support music visualizations.
 */

static const int NUMVIZBUF = 32;
static const int VIZBUFFRAMES = 1024;
static const int TOTALBUFTIMEMSEC = NUMVIZBUF * VIZBUFFRAMES * 1000 / 44100;

static bool gotMem = false;
static sp<MemoryBase> mem[NUMVIZBUF];
static uint64_t timeStamp[NUMVIZBUF];
static uint64_t lastReadTime;
static uint64_t lastWriteTime;
static int writeIdx = 0;

static void allocVizBufs() {
    if (!gotMem) {
        for (int i=0;i<NUMVIZBUF;i++) {
            sp<MemoryHeapBase> heap = new MemoryHeapBase(VIZBUFFRAMES*2, 0, "snooper");
            mem[i] = new MemoryBase(heap, 0, heap->getSize());
            timeStamp[i] = 0;
        }
        gotMem = true;
    }
}


/*
 * Get a buffer of audio data that is about to be played.
 * We don't synchronize this because in practice the writer
 * is ahead of the reader, and even if we did happen to catch
 * a buffer while it's being written, it's just a visualization,
 * so no harm done.
 */
static sp<MemoryBase> getVizBuffer() {

    allocVizBufs();

    lastReadTime = uptimeMillis() + 100; // account for renderer delay (we shouldn't be doing this here)

    // if there is no recent buffer (yet), just return empty handed
    if (lastWriteTime + TOTALBUFTIMEMSEC < lastReadTime) {
        //LOGI("@@@@    no audio data to look at yet");
        return NULL;
    }

    char buf[200];

    int closestIdx = -1;
    uint32_t closestTime = 0x7ffffff;

    for (int i = 0; i < NUMVIZBUF; i++) {
        uint64_t tsi = timeStamp[i];
        uint64_t diff = tsi > lastReadTime ? tsi - lastReadTime : lastReadTime - tsi;
        if (diff < closestTime) {
            closestIdx = i;
            closestTime = diff;
        }
    }


    if (closestIdx >= 0) {
        //LOGI("@@@ return buffer %d, %d/%d", closestIdx, uint32_t(lastReadTime), uint32_t(timeStamp[closestIdx]));
        return mem[closestIdx];
    }

    // we won't get here, since we either bailed out early, or got a buffer
    LOGD("Didn't expect to be here");
    return NULL;
}

static void storeVizBuf(const void *data, int len, uint64_t time) {
    // Copy the data in to the visualizer buffer
    // Assume a 16 bit stereo source for now.
    short *viz = (short*)mem[writeIdx]->pointer();
    short *src = (short*)data;
    for (int i = 0; i < VIZBUFFRAMES; i++) {
        // Degrade quality by mixing to mono and clearing the lowest 3 bits.
        // This should still be good enough for a visualization
        *viz++ = ((int(src[0]) + int(src[1])) >> 1) & ~0x7;
        src += 2;
    }
    timeStamp[writeIdx++] = time;
    if (writeIdx >= NUMVIZBUF) {
        writeIdx = 0;
    }
}

static void makeVizBuffers(const char *data, int len, uint64_t time) {

    allocVizBufs();

    uint64_t startTime = time;
    const int frameSize = 4; // 16 bit stereo sample is 4 bytes
    while (len >= VIZBUFFRAMES * frameSize) {
        storeVizBuf(data, len, time);
        data += VIZBUFFRAMES * frameSize;
        len -= VIZBUFFRAMES * frameSize;
        time += 1000 * VIZBUFFRAMES / 44100;
    }
    //LOGI("@@@ stored buffers from %d to %d", uint32_t(startTime), uint32_t(time));
}

sp<IMemory> MediaPlayerService::snoop()
{
    sp<MemoryBase> mem = getVizBuffer();
    return mem;
}


#undef LOG_TAG
#define LOG_TAG "AudioSink"
MediaPlayerService::AudioOutput::AudioOutput()
    : mCallback(NULL),
      mCallbackCookie(NULL) {
    mTrack = 0;
    mStreamType = AudioSystem::MUSIC;
    mLeftVolume = 1.0;
    mRightVolume = 1.0;
    mLatency = 0;
    mMsecsPerFrame = 0;
    mNumFramesWritten = 0;
    setMinBufferCount();
}

MediaPlayerService::AudioOutput::~AudioOutput()
{
    close();
}

void MediaPlayerService::AudioOutput::setMinBufferCount()
{
    char value[PROPERTY_VALUE_MAX];
    if (property_get("ro.kernel.qemu", value, 0)) {
        mIsOnEmulator = true;
        mMinBufferCount = 12;  // to prevent systematic buffer underrun for emulator
    }
}

bool MediaPlayerService::AudioOutput::isOnEmulator()
{
    setMinBufferCount();
    return mIsOnEmulator;
}

int MediaPlayerService::AudioOutput::getMinBufferCount()
{
    setMinBufferCount();
    return mMinBufferCount;
}

ssize_t MediaPlayerService::AudioOutput::bufferSize() const
{
    if (mTrack == 0) return NO_INIT;
    return mTrack->frameCount() * frameSize();
}

ssize_t MediaPlayerService::AudioOutput::frameCount() const
{
    if (mTrack == 0) return NO_INIT;
    return mTrack->frameCount();
}

ssize_t MediaPlayerService::AudioOutput::channelCount() const
{
    if (mTrack == 0) return NO_INIT;
    return mTrack->channelCount();
}

ssize_t MediaPlayerService::AudioOutput::frameSize() const
{
    if (mTrack == 0) return NO_INIT;
    return mTrack->frameSize();
}

uint32_t MediaPlayerService::AudioOutput::latency () const
{
    return mLatency;
}

float MediaPlayerService::AudioOutput::msecsPerFrame() const
{
    return mMsecsPerFrame;
}

status_t MediaPlayerService::AudioOutput::open(
        uint32_t sampleRate, int channelCount, int format, int bufferCount,
        AudioCallback cb, void *cookie)
{
    mCallback = cb;
    mCallbackCookie = cookie;

    // Check argument "bufferCount" against the mininum buffer count
    if (bufferCount < mMinBufferCount) {
        LOGD("bufferCount (%d) is too small and increased to %d", bufferCount, mMinBufferCount);
        bufferCount = mMinBufferCount;

    }
    LOGV("open(%u, %d, %d, %d)", sampleRate, channelCount, format, bufferCount);
    if (mTrack) close();
    int afSampleRate;
    int afFrameCount;
    int frameCount;

    if (AudioSystem::getOutputFrameCount(&afFrameCount, mStreamType) != NO_ERROR) {
        return NO_INIT;
    }
    if (AudioSystem::getOutputSamplingRate(&afSampleRate, mStreamType) != NO_ERROR) {
        return NO_INIT;
    }

    frameCount = (sampleRate*afFrameCount*bufferCount)/afSampleRate;

    AudioTrack *t;
    if (mCallback != NULL) {
        t = new AudioTrack(
                mStreamType,
                sampleRate,
                format,
                (channelCount == 2) ? AudioSystem::CHANNEL_OUT_STEREO : AudioSystem::CHANNEL_OUT_MONO,
                frameCount,
                0 /* flags */,
                CallbackWrapper,
                this);
    } else {
        t = new AudioTrack(
                mStreamType,
                sampleRate,
                format,
                (channelCount == 2) ? AudioSystem::CHANNEL_OUT_STEREO : AudioSystem::CHANNEL_OUT_MONO,
                frameCount);
    }

    if ((t == 0) || (t->initCheck() != NO_ERROR)) {
        LOGE("Unable to create audio track");
        delete t;
        return NO_INIT;
    }

    LOGV("setVolume");
    t->setVolume(mLeftVolume, mRightVolume);
    mMsecsPerFrame = 1.e3 / (float) sampleRate;
    mLatency = t->latency();
    mTrack = t;
    return NO_ERROR;
}

void MediaPlayerService::AudioOutput::start()
{
    LOGV("start");
    if (mTrack) {
        mTrack->setVolume(mLeftVolume, mRightVolume);
        mTrack->start();
        mTrack->getPosition(&mNumFramesWritten);
    }
}

ssize_t MediaPlayerService::AudioOutput::write(const void* buffer, size_t size)
{
    LOG_FATAL_IF(mCallback != NULL, "Don't call write if supplying a callback.");

    //LOGV("write(%p, %u)", buffer, size);
    if (mTrack) {
        // Only make visualization buffers if anyone recently requested visualization data
        uint64_t now = uptimeMillis();
        if (lastReadTime + TOTALBUFTIMEMSEC >= now) {
            // Based on the current play counter, the number of frames written and
            // the current real time we can calculate the approximate real start
            // time of the buffer we're about to write.
            uint32_t pos;
            mTrack->getPosition(&pos);

            // we're writing ahead by this many frames:
            int ahead = mNumFramesWritten - pos;
            //LOGI("@@@ written: %d, playpos: %d, latency: %d", mNumFramesWritten, pos, mTrack->latency());
            // which is this many milliseconds, assuming 44100 Hz:
            ahead /= 44;

            makeVizBuffers((const char*)buffer, size, now + ahead + mTrack->latency());
            lastWriteTime = now;
        }
        ssize_t ret = mTrack->write(buffer, size);
        mNumFramesWritten += ret / 4; // assume 16 bit stereo
        return ret;
    }
    return NO_INIT;
}

void MediaPlayerService::AudioOutput::stop()
{
    LOGV("stop");
    if (mTrack) mTrack->stop();
    lastWriteTime = 0;
}

void MediaPlayerService::AudioOutput::flush()
{
    LOGV("flush");
    if (mTrack) mTrack->flush();
}

void MediaPlayerService::AudioOutput::pause()
{
    LOGV("pause");
    if (mTrack) mTrack->pause();
    lastWriteTime = 0;
}

void MediaPlayerService::AudioOutput::close()
{
    LOGV("close");
    delete mTrack;
    mTrack = 0;
}

void MediaPlayerService::AudioOutput::setVolume(float left, float right)
{
    LOGV("setVolume(%f, %f)", left, right);
    mLeftVolume = left;
    mRightVolume = right;
    if (mTrack) {
        mTrack->setVolume(left, right);
    }
}

// static
void MediaPlayerService::AudioOutput::CallbackWrapper(
        int event, void *cookie, void *info) {
    if (event != AudioTrack::EVENT_MORE_DATA) {
        return;
    }

    AudioOutput *me = (AudioOutput *)cookie;
    AudioTrack::Buffer *buffer = (AudioTrack::Buffer *)info;

    (*me->mCallback)(
            me, buffer->raw, buffer->size, me->mCallbackCookie);
}

#undef LOG_TAG
#define LOG_TAG "AudioCache"
MediaPlayerService::AudioCache::AudioCache(const char* name) :
    mChannelCount(0), mFrameCount(1024), mSampleRate(0), mSize(0),
    mError(NO_ERROR), mCommandComplete(false)
{
    // create ashmem heap
    mHeap = new MemoryHeapBase(kDefaultHeapSize, 0, name);
}

uint32_t MediaPlayerService::AudioCache::latency () const
{
    return 0;
}

float MediaPlayerService::AudioCache::msecsPerFrame() const
{
    return mMsecsPerFrame;
}

status_t MediaPlayerService::AudioCache::open(
        uint32_t sampleRate, int channelCount, int format, int bufferCount,
        AudioCallback cb, void *cookie)
{
    if (cb != NULL) {
        return UNKNOWN_ERROR;  // TODO: implement this.
    }

    LOGV("open(%u, %d, %d, %d)", sampleRate, channelCount, format, bufferCount);
    if (mHeap->getHeapID() < 0) return NO_INIT;
    mSampleRate = sampleRate;
    mChannelCount = (uint16_t)channelCount;
    mFormat = (uint16_t)format;
    mMsecsPerFrame = 1.e3 / (float) sampleRate;
    return NO_ERROR;
}

ssize_t MediaPlayerService::AudioCache::write(const void* buffer, size_t size)
{
    LOGV("write(%p, %u)", buffer, size);
    if ((buffer == 0) || (size == 0)) return size;

    uint8_t* p = static_cast<uint8_t*>(mHeap->getBase());
    if (p == NULL) return NO_INIT;
    p += mSize;
    LOGV("memcpy(%p, %p, %u)", p, buffer, size);
    if (mSize + size > mHeap->getSize()) {
        LOGE("Heap size overflow! req size: %d, max size: %d", (mSize + size), mHeap->getSize());
        size = mHeap->getSize() - mSize;
    }
    memcpy(p, buffer, size);
    mSize += size;
    return size;
}

// call with lock held
status_t MediaPlayerService::AudioCache::wait()
{
    Mutex::Autolock lock(mLock);
    if (!mCommandComplete) {
        mSignal.wait(mLock);
    }
    mCommandComplete = false;

    if (mError == NO_ERROR) {
        LOGV("wait - success");
    } else {
        LOGV("wait - error");
    }
    return mError;
}

void MediaPlayerService::AudioCache::notify(void* cookie, int msg, int ext1, int ext2)
{
    LOGV("notify(%p, %d, %d, %d)", cookie, msg, ext1, ext2);
    AudioCache* p = static_cast<AudioCache*>(cookie);

    // ignore buffering messages
    if (msg == MEDIA_BUFFERING_UPDATE) return;

    // set error condition
    if (msg == MEDIA_ERROR) {
        LOGE("Error %d, %d occurred", ext1, ext2);
        p->mError = ext1;
    }

    // wake up thread
    LOGV("wakeup thread");
    p->mCommandComplete = true;
    p->mSignal.signal();
}

} // namespace android