Make the rate limiting of Native Client Plugin progress events

more robust by using time rather than bytes downloaded to determine when to fire another event.
BUG=none
TEST=manual, working on an example.
Review URL: http://codereview.chromium.org/8548018

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@111421 0039d316-1c4b-4281-b951-d872f2087c98

2 files changed, 16 insertions, 11 deletions

diff --git a/ppapi/native_client/src/trusted/plugin/plugin.cc b/ppapi/native_client/src/trusted/plugin/plugin.cc
index 4fb8a0c..5409907 100644
--- a/ppapi/native_client/src/trusted/plugin/plugin.cc
+++ b/ppapi/native_client/src/trusted/plugin/plugin.cc
@@ -985,7 +985,7 @@ Plugin::Plugin(PP_Instance pp_instance)
       init_time_(0),
       ready_time_(0),
       nexe_size_(0),
-      last_event_bytes_received_(0) {
+      time_of_last_progress_event_(0) {
   PLUGIN_PRINTF(("Plugin::Plugin (this=%p, pp_instance=%"
                  NACL_PRId32")\n", static_cast<void*>(this), pp_instance));
   NaClSrpcModuleInit();
@@ -1843,23 +1843,28 @@ void Plugin::UpdateDownloadProgress(
   Instance* instance = pp::Module::Get()->InstanceForPPInstance(pp_instance);
   if (instance != NULL) {
     Plugin* plugin = static_cast<Plugin*>(instance);
-    int64_t progress = bytes_received - plugin->last_event_bytes_received_;
-    const int64_t kProgressThreshold = 1 << 17;  // 128K bytes per event
-    if (progress > kProgressThreshold) {
-      LengthComputable length_computable = (total_bytes_to_be_received >= 0) ?
-          LENGTH_IS_COMPUTABLE : LENGTH_IS_NOT_COMPUTABLE;
-      // Get the URL for the URL loader that sent this notification.
+    // Rate limit progress events to a maximum of 100 per second.
+    int64_t time = NaClGetTimeOfDayMicroseconds();
+    int64_t elapsed = time - plugin->time_of_last_progress_event_;
+    const int64_t kTenMilliseconds = 10000;
+    if (elapsed > kTenMilliseconds) {
+      plugin->time_of_last_progress_event_ = time;
+
+      // Find the URL loader that sent this notification.
       const FileDownloader* file_downloader =
           plugin->FindFileDownloader(pp_resource);
-      nacl::string url = (file_downloader != NULL) ?
-          file_downloader->url_to_open() : NACL_NO_URL;
+      // If not a streamed file, it must be the .nexe loader.
+      if (file_downloader == NULL)
+        file_downloader = &plugin->nexe_downloader_;
+      nacl::string url = file_downloader->url_to_open();
+      LengthComputable length_computable = (total_bytes_to_be_received >= 0) ?
+          LENGTH_IS_COMPUTABLE : LENGTH_IS_NOT_COMPUTABLE;
 
       plugin->EnqueueProgressEvent(kProgressEventProgress,
                                    url,
                                    length_computable,
                                    bytes_received,
                                    total_bytes_to_be_received);
-      plugin->last_event_bytes_received_ = bytes_received;
     }
   }
 }
diff --git a/ppapi/native_client/src/trusted/plugin/plugin.h b/ppapi/native_client/src/trusted/plugin/plugin.h
index 966933b..090b4bf 100644
--- a/ppapi/native_client/src/trusted/plugin/plugin.h
+++ b/ppapi/native_client/src/trusted/plugin/plugin.h
@@ -560,7 +560,7 @@ class Plugin : public pp::InstancePrivate {
   // downloaded.
   const FileDownloader* FindFileDownloader(PP_Resource url_loader) const;
 
-  int64_t last_event_bytes_received_;
+  int64_t time_of_last_progress_event_;
 };
 
 }  // namespace plugin