Initial support for Renderer Side Histograms

Patch contributed by Raman Tenneti

see also patch number 21038

Review URL: http://codereview.chromium.org/27034

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@10330 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 94 insertions, 0 deletions

diff --git a/chrome/renderer/renderer_histogram_snapshots.cc b/chrome/renderer/renderer_histogram_snapshots.cc
new file mode 100644
index 0000000..a4488ca
--- /dev/null
+++ b/chrome/renderer/renderer_histogram_snapshots.cc
@@ -0,0 +1,94 @@
+// Copyright (c) 2006-2008 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "chrome/renderer/renderer_histogram_snapshots.h"
+
+#include <ctype.h>
+
+#include "base/histogram.h"
+#include "base/logging.h"
+#include "base/message_loop.h"
+#include "base/pickle.h"
+#include "chrome/common/render_messages.h"
+#include "chrome/renderer/render_process.h"
+#include "chrome/renderer/render_thread.h"
+
+// TODO(raman): Before renderer shuts down send final snapshot lists.
+
+RendererHistogramSnapshots::RendererHistogramSnapshots()
+    : ALLOW_THIS_IN_INITIALIZER_LIST(
+        renderer_histogram_snapshots_factory_(this)) {
+}
+
+// Send data quickly!
+void RendererHistogramSnapshots::SendHistograms() {
+  RenderThread::current()->message_loop()->PostTask(FROM_HERE,
+      renderer_histogram_snapshots_factory_.NewRunnableMethod(
+          &RendererHistogramSnapshots::UploadAllHistrograms));
+}
+
+void RendererHistogramSnapshots::UploadAllHistrograms() {
+  StatisticsRecorder::Histograms histograms;
+  StatisticsRecorder::GetHistograms(&histograms);
+
+  HistogramPickledList pickled_histograms;
+
+  for (StatisticsRecorder::Histograms::iterator it = histograms.begin();
+       histograms.end() != it;
+       it++) {
+    UploadHistrogram(**it, &pickled_histograms);
+  }
+  // Send the handle over synchronous IPC.
+  if (pickled_histograms.size() > 0) {
+    RenderThread::current()->Send(
+        new ViewHostMsg_RendererHistograms(pickled_histograms));
+  }
+}
+
+// Extract snapshot data and then send it off the the Browser process
+// to save it.
+void RendererHistogramSnapshots::UploadHistrogram(
+    const Histogram& histogram,
+    HistogramPickledList* pickled_histograms) {
+
+  // Get up-to-date snapshot of sample stats.
+  Histogram::SampleSet snapshot;
+  histogram.SnapshotSample(&snapshot);
+  const std::string& histogram_name = histogram.histogram_name();
+
+  // Find the already sent stats, or create an empty set.
+  LoggedSampleMap::iterator it = logged_samples_.find(histogram_name);
+  Histogram::SampleSet* already_logged;
+  if (logged_samples_.end() == it) {
+    // Add new entry.
+    already_logged = &logged_samples_[histogram.histogram_name()];
+    already_logged->Resize(histogram);  // Complete initialization.
+  } else {
+    already_logged = &(it->second);
+    // Deduct any stats we've already logged from our snapshot.
+    snapshot.Subtract(*already_logged);
+  }
+
+  // Snapshot now contains only a delta to what we've already_logged.
+
+  if (snapshot.TotalCount() > 0) {
+    UploadHistogramDelta(histogram, snapshot, pickled_histograms);
+    // Add new data into our running total.
+    already_logged->Add(snapshot);
+  }
+}
+
+void RendererHistogramSnapshots::UploadHistogramDelta(
+    const Histogram& histogram,
+    const Histogram::SampleSet& snapshot,
+    HistogramPickledList* pickled_histograms) {
+
+  DCHECK(0 != snapshot.TotalCount());
+  snapshot.CheckSize(histogram);
+
+  std::string histogram_info =
+      Histogram::SerializeHistogramInfo(histogram, snapshot);
+  pickled_histograms->push_back(histogram_info);
+}
+