Merge pull request #465 from Ood-Tsen/contentDataSource

support content uri (e.q. content://xxx)

library/src/main/java/com/google/android/exoplayer/upstream/ContentDataSource.java

+/*
+ * Copyright (C) 2014 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.
+ */
+package com.google.android.exoplayer.upstream;
+
+import android.content.ContentResolver;
+import android.content.Context;
+import android.content.res.AssetFileDescriptor;
+
+import com.google.android.exoplayer.C;
+
+import java.io.FileDescriptor;
+import java.io.FileInputStream;
+import java.io.IOException;
+import java.io.InputStream;
+
+/**
+ * This calll is support content uri and file uri (e.q. content:// , file://). 
+ * {@link DataSource}.
+ */
+public final class ContentDataSource implements UriDataSource {
+  static private final String TAG = "ContentDataSource";
+  /**
+   * Thrown when IOException is encountered during local asset read operation.
+   */
+  public static class ContentDataSourceException extends IOException {
+
+    public ContentDataSourceException(IOException cause) {
+      super(cause);
+    }
+
+  }
+
+  private final TransferListener listener;
+
+  private InputStream inputStream;
+  private Context context;
+  private String uri;
+  private long bytesRemaining;
+  private boolean opened;
+
+  /**
+   * Constructs a new {@link DataSource} that retrieves data from a content provider.
+   */
+  public ContentDataSource(Context context) {
+    this(context, null);
+  }
+
+  /**
+   * Constructs a new {@link DataSource} that retrieves data from a content provider.
+   *
+   * @param listener An optional listener. Specify {@code null} for no listener.
+   */
+  public ContentDataSource(Context context, TransferListener listener) {
+    this.context = context;
+    this.listener = listener;
+  }
+
+  @Override
+  public long open(DataSpec dataSpec) throws IOException {
+    try {
+      uri = dataSpec.uri.toString();
+      inputStream = new FileInputStream(getFileDescriptor(context, dataSpec));
+      inputStream.skip(dataSpec.position);
+      bytesRemaining = dataSpec.length == C.LENGTH_UNBOUNDED ? inputStream.available()
+          : dataSpec.length;
+      if (bytesRemaining < 0) {
+        throw new IOException();
+      }
+    } catch (IOException e) {
+      throw new IOException(e);
+    }
+
+    opened = true;
+    if (listener != null) {
+      listener.onTransferStart();
+    }
+
+    return bytesRemaining;
+  }
+
+  @Override
+  public int read(byte[] buffer, int offset, int readLength) throws IOException {
+    if (bytesRemaining == 0) {
+      return -1;
+    } else {
+      int bytesRead = 0;
+      try {
+        bytesRead = inputStream.read(buffer, offset, (int) Math.min(bytesRemaining, readLength));
+      } catch (IOException e) {
+        throw new IOException(e);
+      }
+
+      if (bytesRead > 0) {
+        bytesRemaining -= bytesRead;
+        if (listener != null) {
+          listener.onBytesTransferred(bytesRead);
+        }
+      }
+
+      return bytesRead;
+    }
+  }
+
+  @Override
+  public String getUri() {
+    return uri;
+  }
+
+  @Override
+  public void close() throws ContentDataSourceException {
+    if (inputStream != null) {
+      try {
+        inputStream.close();
+      } catch (IOException e) {
+        throw new ContentDataSourceException(e);
+      } finally {
+        inputStream = null;
+        uri = null;
+
+        if (opened) {
+          opened = false;
+          if (listener != null) {
+            listener.onTransferEnd();
+          }
+        }
+      }
+    }
+  }
+
+  /**
+   * query the fileDescriptor from conten resolver.
+   *
+   */
+  private static FileDescriptor getFileDescriptor(Context context, DataSpec dataSpec) throws IOException {
+    try {
+      ContentResolver resolver = context.getContentResolver();
+      AssetFileDescriptor fd = resolver.openAssetFileDescriptor(dataSpec.uri, "r");
+      return fd.getFileDescriptor();
+    } catch (IOException e) {
+      throw new IOException(e);
+    }
+  }
+}