Android下的PVPlayer的实现(2)

2、 两种设置源的方式 setDataSource，一个是打开一个文件重头开始，一个事从文件的中间开始。

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);//由content得到文件的句柄
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;
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;
}