Send estimated bandwidth value as informational event when cache fetcher pauses

o Application can make informed decision about the available network bandwidth
  when cache fetcher pauses.

o Application can also adjust how frequently the bandwidth is estimated within
  a range from one second to one minute.

Change-Id: I90068001343e79da1886de03c565537787e1580b

1 files changed, 78 insertions, 1 deletions

diff --git a/media/libstagefright/HTTPBase.cpp b/media/libstagefright/HTTPBase.cpp
index 58b17a7..c0ae29d 100644
--- a/media/libstagefright/HTTPBase.cpp
+++ b/media/libstagefright/HTTPBase.cpp
@@ -14,6 +14,10 @@
  * limitations under the License.
  */
 
+//#define LOG_NDEBUG 0
+#define LOG_TAG "HTTPBase"
+#include <utils/Log.h>
+
 #include "include/HTTPBase.h"
 
 #if CHROMIUM_AVAILABLE
@@ -22,11 +26,19 @@
 
 #include "include/NuHTTPDataSource.h"
 
+#include <media/stagefright/foundation/ALooper.h>
 #include <cutils/properties.h>
 
 namespace android {
 
-HTTPBase::HTTPBase() {}
+HTTPBase::HTTPBase()
+    : mNumBandwidthHistoryItems(0),
+      mTotalTransferTimeUs(0),
+      mTotalTransferBytes(0),
+      mPrevBandwidthMeasureTimeUs(0),
+      mPrevEstimatedBandWidthKbps(0),
+      mBandWidthCollectFreqMs(5000) {
+}
 
 // static
 sp<HTTPBase> HTTPBase::Create(uint32_t flags) {
@@ -42,4 +54,69 @@ sp<HTTPBase> HTTPBase::Create(uint32_t flags) {
     }
 }
 
+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 > 100) {
+        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);
+
+    if (mNumBandwidthHistoryItems < 2) {
+        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) {
+
+        LOGE("frequency (%d ms) is out of range [1000, 60000]", freqMs);
+        return BAD_VALUE;
+    }
+
+    LOGI("frequency set to %d ms", freqMs);
+    mBandWidthCollectFreqMs = freqMs;
+    return OK;
+}
+
 }  // namespace android