LiveSession: Add support for block-by-block fetchFile.
Bug: 11854054
Change-Id: I4025ba7fab8fab2e0c720f73894e908fd98a43d8
diff --git a/media/libstagefright/httplive/LiveSession.cpp b/media/libstagefright/httplive/LiveSession.cpp
index bd12ddc..0333a2a 100644
--- a/media/libstagefright/httplive/LiveSession.cpp
+++ b/media/libstagefright/httplive/LiveSession.cpp
@@ -512,53 +512,80 @@
return info.mFetcher;
}
+/*
+ * Illustration of parameters:
+ *
+ * 0 `range_offset`
+ * +------------+-------------------------------------------------------+--+--+
+ * | | | next block to fetch | | |
+ * | | `source` handle => `out` buffer | | | |
+ * | `url` file |<--------- buffer size --------->|<--- `block_size` -->| | |
+ * | |<----------- `range_length` / buffer capacity ----------->| |
+ * |<------------------------------ file_size ------------------------------->|
+ *
+ * Special parameter values:
+ * - range_length == -1 means entire file
+ * - block_size == 0 means entire range
+ *
+ */
status_t LiveSession::fetchFile(
const char *url, sp<ABuffer> *out,
- int64_t range_offset, int64_t range_length) {
- *out = NULL;
-
- sp<DataSource> source;
-
- if (!strncasecmp(url, "file://", 7)) {
- source = new FileSource(url + 7);
- } else if (strncasecmp(url, "http://", 7)
- && strncasecmp(url, "https://", 8)) {
- return ERROR_UNSUPPORTED;
- } else {
- KeyedVector<String8, String8> headers = mExtraHeaders;
- if (range_offset > 0 || range_length >= 0) {
- headers.add(
- String8("Range"),
- String8(
- StringPrintf(
- "bytes=%lld-%s",
- range_offset,
- range_length < 0
- ? "" : StringPrintf("%lld", range_offset + range_length - 1).c_str()).c_str()));
- }
- status_t err = mHTTPDataSource->connect(url, &headers);
-
- if (err != OK) {
- return err;
- }
-
- source = mHTTPDataSource;
+ int64_t range_offset, int64_t range_length,
+ uint32_t block_size, /* download block size */
+ sp<DataSource> *source /* to return and reuse source */) {
+ off64_t size;
+ sp<DataSource> temp_source;
+ if (source == NULL) {
+ source = &temp_source;
}
- off64_t size;
- status_t err = source->getSize(&size);
+ if (*source == NULL) {
+ if (!strncasecmp(url, "file://", 7)) {
+ *source = new FileSource(url + 7);
+ } else if (strncasecmp(url, "http://", 7)
+ && strncasecmp(url, "https://", 8)) {
+ return ERROR_UNSUPPORTED;
+ } else {
+ KeyedVector<String8, String8> headers = mExtraHeaders;
+ if (range_offset > 0 || range_length >= 0) {
+ headers.add(
+ String8("Range"),
+ String8(
+ StringPrintf(
+ "bytes=%lld-%s",
+ range_offset,
+ range_length < 0
+ ? "" : StringPrintf("%lld",
+ range_offset + range_length - 1).c_str()).c_str()));
+ }
+ status_t err = mHTTPDataSource->connect(url, &headers);
- if (err != OK) {
+ if (err != OK) {
+ return err;
+ }
+
+ *source = mHTTPDataSource;
+ }
+ }
+
+ status_t getSizeErr = (*source)->getSize(&size);
+ if (getSizeErr != OK) {
size = 65536;
}
- sp<ABuffer> buffer = new ABuffer(size);
- buffer->setRange(0, 0);
+ sp<ABuffer> buffer = *out != NULL ? *out : new ABuffer(size);
+ if (*out == NULL) {
+ buffer->setRange(0, 0);
+ }
+ // adjust range_length if only reading partial block
+ if (block_size > 0 && (range_length == -1 || buffer->size() + block_size < range_length)) {
+ range_length = buffer->size() + block_size;
+ }
for (;;) {
+ // Only resize when we don't know the size.
size_t bufferRemaining = buffer->capacity() - buffer->size();
-
- if (bufferRemaining == 0) {
+ if (bufferRemaining == 0 && getSizeErr != OK) {
bufferRemaining = 32768;
ALOGV("increasing download buffer to %d bytes",
@@ -583,7 +610,9 @@
}
}
- ssize_t n = source->readAt(
+ // The DataSource is responsible for informing us of error (n < 0) or eof (n == 0)
+ // to help us break out of the loop.
+ ssize_t n = (*source)->readAt(
buffer->size(), buffer->data() + buffer->size(),
maxBytesToRead);
diff --git a/media/libstagefright/httplive/LiveSession.h b/media/libstagefright/httplive/LiveSession.h
index 99b480a8..f42d7ae 100644
--- a/media/libstagefright/httplive/LiveSession.h
+++ b/media/libstagefright/httplive/LiveSession.h
@@ -145,9 +145,25 @@
status_t onSeek(const sp<AMessage> &msg);
void onFinishDisconnect2();
+ // If given a non-zero block_size (default 0), it is used to cap the number of
+ // bytes read in from the DataSource. If given a non-NULL buffer, new content
+ // is read into the end.
+ //
+ // The DataSource we read from is responsible for signaling error or EOF to help us
+ // break out of the read loop. The DataSource can be returned to the caller, so
+ // that the caller can reuse it for subsequent fetches (within the initially
+ // requested range).
+ //
+ // For reused HTTP sources, the caller must download a file sequentially without
+ // any overlaps or gaps to prevent reconnection.
status_t fetchFile(
const char *url, sp<ABuffer> *out,
- int64_t range_offset = 0, int64_t range_length = -1);
+ /* request/open a file starting at range_offset for range_length bytes */
+ int64_t range_offset = 0, int64_t range_length = -1,
+ /* download block size */
+ uint32_t block_size = 0,
+ /* reuse DataSource if doing partial fetch */
+ sp<DataSource> *source = NULL);
sp<M3UParser> fetchPlaylist(
const char *url, uint8_t *curPlaylistHash, bool *unchanged);
