LiveSession: Use the actual, possibly redirected url as base in the M3U

This fixes playback of HLS streams where the M3U playlists use
relative paths and the main playlist is opened via a redirect.

Change-Id: I787e1c050daddc566be4c8e3f84803d3f91eec46
diff --git a/media/libstagefright/httplive/LiveSession.cpp b/media/libstagefright/httplive/LiveSession.cpp
index bd12ddc..d4fd2b3 100644
--- a/media/libstagefright/httplive/LiveSession.cpp
+++ b/media/libstagefright/httplive/LiveSession.cpp
@@ -514,7 +514,8 @@
 
 status_t LiveSession::fetchFile(
         const char *url, sp<ABuffer> *out,
-        int64_t range_offset, int64_t range_length) {
+        int64_t range_offset, int64_t range_length,
+        String8 *actualUrl) {
     *out = NULL;
 
     sp<DataSource> source;
@@ -599,6 +600,12 @@
     }
 
     *out = buffer;
+    if (actualUrl != NULL) {
+        *actualUrl = source->getUri();
+        if (actualUrl->isEmpty()) {
+            *actualUrl = url;
+        }
+    }
 
     return OK;
 }
@@ -610,7 +617,8 @@
     *unchanged = false;
 
     sp<ABuffer> buffer;
-    status_t err = fetchFile(url, &buffer);
+    String8 actualUrl;
+    status_t err = fetchFile(url, &buffer, 0, -1, &actualUrl);
 
     if (err != OK) {
         return NULL;
@@ -644,7 +652,7 @@
 #endif
 
     sp<M3UParser> playlist =
-        new M3UParser(url, buffer->data(), buffer->size());
+        new M3UParser(actualUrl.string(), buffer->data(), buffer->size());
 
     if (playlist->initCheck() != OK) {
         ALOGE("failed to parse .m3u8 playlist");
diff --git a/media/libstagefright/httplive/LiveSession.h b/media/libstagefright/httplive/LiveSession.h
index 99b480a8..8f6a4ea 100644
--- a/media/libstagefright/httplive/LiveSession.h
+++ b/media/libstagefright/httplive/LiveSession.h
@@ -147,7 +147,8 @@
 
     status_t fetchFile(
             const char *url, sp<ABuffer> *out,
-            int64_t range_offset = 0, int64_t range_length = -1);
+            int64_t range_offset = 0, int64_t range_length = -1,
+            String8 *actualUrl = NULL);
 
     sp<M3UParser> fetchPlaylist(
             const char *url, uint8_t *curPlaylistHash, bool *unchanged);