Split datasource out of libstagefright

into libdatasource, which contains:
  DataSourceFactory
  (Clear)FileSource
  (Clear)MediaHTTP
  DataURISource
  HTTPBase
  NuCachedSource2

This is needed to break a circular dependency in an upcoming CL.

Test: build, boot

Change-Id: I34d9937235c78f18f51b18945342a0743e209577
Merged-In: I34d9937235c78f18f51b18945342a0743e209577
diff --git a/media/libdatasource/HTTPBase.cpp b/media/libdatasource/HTTPBase.cpp
new file mode 100644
index 0000000..ef29c48
--- /dev/null
+++ b/media/libdatasource/HTTPBase.cpp
@@ -0,0 +1,115 @@
+/*
+ * Copyright (C) 2011 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 "HTTPBase"
+#include <utils/Log.h>
+
+#include <datasource/HTTPBase.h>
+
+#include <media/stagefright/foundation/ADebug.h>
+#include <media/stagefright/foundation/ALooper.h>
+
+#include <cutils/properties.h>
+#include <cutils/qtaguid.h>
+
+namespace android {
+
+HTTPBase::HTTPBase()
+    : mNumBandwidthHistoryItems(0),
+      mTotalTransferTimeUs(0),
+      mTotalTransferBytes(0),
+      mMaxBandwidthHistoryItems(100),
+      mPrevBandwidthMeasureTimeUs(0),
+      mPrevEstimatedBandWidthKbps(0),
+      mBandWidthCollectFreqMs(5000) {
+    mName = String8("HTTPBase(<disconnected>)");
+}
+
+void HTTPBase::addBandwidthMeasurement(
+        size_t numBytes, int64_t delayUs) {
+    Mutex::Autolock autoLock(mLock);
+
+    BandwidthEntry entry;
+    entry.mDelayUs = delayUs;
+    entry.mNumBytes = numBytes;
+    mTotalTransferTimeUs += delayUs;
+    mTotalTransferBytes += numBytes;
+
+    mBandwidthHistory.push_back(entry);
+    if (++mNumBandwidthHistoryItems > mMaxBandwidthHistoryItems) {
+        BandwidthEntry *entry = &*mBandwidthHistory.begin();
+        mTotalTransferTimeUs -= entry->mDelayUs;
+        mTotalTransferBytes -= entry->mNumBytes;
+        mBandwidthHistory.erase(mBandwidthHistory.begin());
+        --mNumBandwidthHistoryItems;
+
+        int64_t timeNowUs = ALooper::GetNowUs();
+        if (timeNowUs - mPrevBandwidthMeasureTimeUs >=
+                mBandWidthCollectFreqMs * 1000LL) {
+
+            if (mPrevBandwidthMeasureTimeUs != 0) {
+                mPrevEstimatedBandWidthKbps =
+                    (mTotalTransferBytes * 8E3 / mTotalTransferTimeUs);
+            }
+            mPrevBandwidthMeasureTimeUs = timeNowUs;
+        }
+    }
+
+}
+
+bool HTTPBase::estimateBandwidth(int32_t *bandwidth_bps) {
+    Mutex::Autolock autoLock(mLock);
+
+    // Do not do bandwidth estimation if we don't have enough samples, or
+    // total bytes download are too small (<64K).
+    // Bandwidth estimation from these samples can often shoot up and cause
+    // unwanted bw adaption behaviors.
+    if (mNumBandwidthHistoryItems < 2 || mTotalTransferBytes < 65536) {
+        return false;
+    }
+
+    *bandwidth_bps = ((double)mTotalTransferBytes * 8E6 / mTotalTransferTimeUs);
+
+    return true;
+}
+
+status_t HTTPBase::getEstimatedBandwidthKbps(int32_t *kbps) {
+    Mutex::Autolock autoLock(mLock);
+    *kbps = mPrevEstimatedBandWidthKbps;
+    return OK;
+}
+
+status_t HTTPBase::setBandwidthStatCollectFreq(int32_t freqMs) {
+    Mutex::Autolock autoLock(mLock);
+
+    if (freqMs < kMinBandwidthCollectFreqMs
+            || freqMs > kMaxBandwidthCollectFreqMs) {
+
+        ALOGE("frequency (%d ms) is out of range [1000, 60000]", freqMs);
+        return BAD_VALUE;
+    }
+
+    ALOGI("frequency set to %d ms", freqMs);
+    mBandWidthCollectFreqMs = freqMs;
+    return OK;
+}
+
+void HTTPBase::setBandwidthHistorySize(size_t numHistoryItems) {
+    mMaxBandwidthHistoryItems = numHistoryItems;
+}
+
+}  // namespace android