Unhide the android.media.[Media]DataSource interface.

This allows apps to implement MediaDataSource, which is modeled on
stagefright's DataSource, to supply media data to the framework. This
was already implemented for MediaExtractor, but it was renamed from
DataSource.

MediaExtractor, MediaPlayer and MediaMetadataRetriever each have a new
overload: #setDataSource(android.media.MediaDataSource)

Only NuPlayer supports this new data source.

The change introduces:
 * IDataSource:        The binder interface for DataSource.
 * JMediaDataSource:   The native counterpart to the java interface. It
                       implements IDataSource.
 * CallbackDataSource: A stagefright DataSource that wraps an
                       IDataSource.

Change-Id: Ib3c944b49cc8a792c8eb9c85e5015c07f298ebc1

1 files changed, 97 insertions, 0 deletions

diff --git a/media/libstagefright/CallbackDataSource.cpp b/media/libstagefright/CallbackDataSource.cpp
new file mode 100644
index 0000000..e16cef7
--- /dev/null
+++ b/media/libstagefright/CallbackDataSource.cpp
@@ -0,0 +1,97 @@
+/*
+ * Copyright 2015 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.
+ */
+
+//#define LOG_NDEBUG 0
+#define LOG_TAG "CallbackDataSource"
+#include <utils/Log.h>
+
+#include "include/CallbackDataSource.h"
+
+#include <binder/IMemory.h>
+#include <media/IDataSource.h>
+#include <media/stagefright/foundation/ADebug.h>
+
+#include <algorithm>
+
+namespace android {
+
+CallbackDataSource::CallbackDataSource(
+    const sp<IDataSource>& binderDataSource)
+    : mIDataSource(binderDataSource) {
+    // Set up the buffer to read into.
+    mMemory = mIDataSource->getIMemory();
+}
+
+CallbackDataSource::~CallbackDataSource() {
+    ALOGV("~CallbackDataSource");
+    mIDataSource->close();
+}
+
+status_t CallbackDataSource::initCheck() const {
+    if (mMemory == NULL) {
+        return UNKNOWN_ERROR;
+    }
+    return OK;
+}
+
+ssize_t CallbackDataSource::readAt(off64_t offset, void* data, size_t size) {
+    if (mMemory == NULL) {
+        return -1;
+    }
+
+    // IDataSource can only read up to mMemory->size() bytes at a time, but this
+    // method should be able to read any number of bytes, so read in a loop.
+    size_t totalNumRead = 0;
+    size_t numLeft = size;
+    const size_t bufferSize = mMemory->size();
+
+    while (numLeft > 0) {
+        size_t numToRead = std::min(numLeft, bufferSize);
+        ssize_t numRead =
+            mIDataSource->readAt(offset + totalNumRead, numToRead);
+        // A negative return value represents an error. Pass it on.
+        if (numRead < 0) {
+            return numRead;
+        }
+        // A zero return value signals EOS. Return the bytes read so far.
+        if (numRead == 0) {
+            return totalNumRead;
+        }
+        // Sanity check.
+        CHECK((size_t)numRead <= numToRead && numRead >= 0 &&
+              numRead <= bufferSize);
+        memcpy(((uint8_t*)data) + totalNumRead, mMemory->pointer(), numRead);
+        numLeft -= numRead;
+        totalNumRead += numRead;
+    }
+
+    return totalNumRead;
+}
+
+status_t CallbackDataSource::getSize(off64_t *size) {
+    status_t err = mIDataSource->getSize(size);
+    if (err != OK) {
+        return err;
+    }
+    if (*size < 0) {
+        // IDataSource will set size to -1 to indicate unknown size, but
+        // DataSource returns ERROR_UNSUPPORTED for that.
+        return ERROR_UNSUPPORTED;
+    }
+    return OK;
+}
+
+} // namespace android