diff --git a/media/libdatasource/FileSource.cpp b/media/libdatasource/FileSource.cpp
new file mode 100644
index 0000000..65780e3
--- /dev/null
+++ b/media/libdatasource/FileSource.cpp
@@ -0,0 +1,155 @@
+/*
+ * Copyright (C) 2009 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 "FileSource"
+#include <utils/Log.h>
+
+#include <datasource/FileSource.h>
+#include <media/stagefright/foundation/ADebug.h>
+#include <private/android_filesystem_config.h>
+
+namespace android {
+
+FileSource::FileSource(const char *filename)
+    : ClearFileSource(filename),
+      mDecryptHandle(NULL),
+      mDrmManagerClient(NULL),
+      mDrmBufOffset(0),
+      mDrmBufSize(0),
+      mDrmBuf(NULL){
+}
+
+FileSource::FileSource(int fd, int64_t offset, int64_t length)
+    : ClearFileSource(fd, offset, length),
+      mDecryptHandle(NULL),
+      mDrmManagerClient(NULL),
+      mDrmBufOffset(0),
+      mDrmBufSize(0),
+      mDrmBuf(NULL) {
+}
+
+FileSource::~FileSource() {
+    if (mDrmBuf != NULL) {
+        delete[] mDrmBuf;
+        mDrmBuf = NULL;
+    }
+
+    if (mDecryptHandle != NULL) {
+        // To release mDecryptHandle
+        CHECK(mDrmManagerClient);
+        mDrmManagerClient->closeDecryptSession(mDecryptHandle);
+        mDecryptHandle = NULL;
+    }
+
+    if (mDrmManagerClient != NULL) {
+        delete mDrmManagerClient;
+        mDrmManagerClient = NULL;
+    }
+}
+
+ssize_t FileSource::readAt(off64_t offset, void *data, size_t size) {
+    if (mFd < 0) {
+        return NO_INIT;
+    }
+
+    Mutex::Autolock autoLock(mLock);
+
+    if (mLength >= 0) {
+        if (offset >= mLength) {
+            return 0;  // read beyond EOF.
+        }
+        uint64_t numAvailable = mLength - offset;
+        if ((uint64_t)size > numAvailable) {
+            size = numAvailable;
+        }
+    }
+
+    if (mDecryptHandle != NULL && DecryptApiType::CONTAINER_BASED
+            == mDecryptHandle->decryptApiType) {
+        return readAtDRM_l(offset, data, size);
+   } else {
+        return readAt_l(offset, data, size);
+    }
+}
+
+sp<DecryptHandle> FileSource::DrmInitialization(const char *mime) {
+    if (getuid() == AID_MEDIA_EX) return nullptr; // no DRM in media extractor
+    if (mDrmManagerClient == NULL) {
+        mDrmManagerClient = new DrmManagerClient();
+    }
+
+    if (mDrmManagerClient == NULL) {
+        return NULL;
+    }
+
+    if (mDecryptHandle == NULL) {
+        mDecryptHandle = mDrmManagerClient->openDecryptSession(
+                mFd, mOffset, mLength, mime);
+    }
+
+    if (mDecryptHandle == NULL) {
+        delete mDrmManagerClient;
+        mDrmManagerClient = NULL;
+    }
+
+    return mDecryptHandle;
+}
+
+ssize_t FileSource::readAtDRM_l(off64_t offset, void *data, size_t size) {
+    size_t DRM_CACHE_SIZE = 1024;
+    if (mDrmBuf == NULL) {
+        mDrmBuf = new unsigned char[DRM_CACHE_SIZE];
+    }
+
+    if (mDrmBuf != NULL && mDrmBufSize > 0 && (offset + mOffset) >= mDrmBufOffset
+            && (offset + mOffset + size) <= static_cast<size_t>(mDrmBufOffset + mDrmBufSize)) {
+        /* Use buffered data */
+        memcpy(data, (void*)(mDrmBuf+(offset+mOffset-mDrmBufOffset)), size);
+        return size;
+    } else if (size <= DRM_CACHE_SIZE) {
+        /* Buffer new data */
+        mDrmBufOffset =  offset + mOffset;
+        mDrmBufSize = mDrmManagerClient->pread(mDecryptHandle, mDrmBuf,
+                DRM_CACHE_SIZE, offset + mOffset);
+        if (mDrmBufSize > 0) {
+            int64_t dataRead = 0;
+            dataRead = size > static_cast<size_t>(mDrmBufSize) ? mDrmBufSize : size;
+            memcpy(data, (void*)mDrmBuf, dataRead);
+            return dataRead;
+        } else {
+            return mDrmBufSize;
+        }
+    } else {
+        /* Too big chunk to cache. Call DRM directly */
+        return mDrmManagerClient->pread(mDecryptHandle, data, size, offset + mOffset);
+    }
+}
+
+/* static */
+bool FileSource::requiresDrm(int fd, int64_t offset, int64_t length, const char *mime) {
+    std::unique_ptr<DrmManagerClient> drmClient(new DrmManagerClient());
+    sp<DecryptHandle> decryptHandle =
+            drmClient->openDecryptSession(fd, offset, length, mime);
+    bool requiresDrm = false;
+    if (decryptHandle != nullptr) {
+        requiresDrm = decryptHandle->decryptApiType == DecryptApiType::CONTAINER_BASED;
+        drmClient->closeDecryptSession(decryptHandle);
+    }
+    return requiresDrm;
+}
+
+}  // namespace android