Wire up windowless plugins. Mostly Mac related, some cross

chrome/plugin/plugin_main.cc

 // 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 "build/build_config.h"
 
 #if defined(OS_WIN)
 #include "app/win_util.h"
 #endif
 #include "base/command_line.h"
 #include "base/message_loop.h"
 #include "base/string_util.h"
 #include "base/system_monitor.h"
 #include "build/build_config.h"
 #include "chrome/common/child_process.h"
 #include "chrome/common/chrome_constants.h"
 #include "chrome/common/chrome_switches.h"
 #include "chrome/common/logging_chrome.h"
 #include "chrome/common/main_function_params.h"
 #include "chrome/plugin/plugin_thread.h"
 
 #if defined(OS_WIN)
 #include "chrome/test/injection_test_dll.h"
 #include "sandbox/src/sandbox.h"
 #elif defined(OS_LINUX)
 #include "chrome/common/chrome_descriptors.h"
 #include "base/global_descriptors_posix.h"
 #endif
 
+#if defined(OS_MACOSX)
+
+// To support Mac NPAPI plugins that use the Carbon event model (i.e., most
+// shipping plugins for MacOS X 10.5 and earlier), we need some way for the
+// Carbon event dispatcher to run, even though the plugin host process itself
+// does not use Carbon events.  Rather than give control to the standard
+// Carbon event loop, we schedule a periodic task on the main thread which
+// empties the Carbon event queue every 20ms (chosen to match how often Safari
+// does the equivalent operation).  This allows plugins to receive idle events
+// and schedule Carbon timers without swamping the CPU.  If, in the future,
+// we remove support for the Carbon event model and only support the Cocoa
+// event model, this can be removed.  Note that this approach does not install
+// standard application event handlers for the menubar, AppleEvents, and so on.
+// This is intentional, since the plugin process is not actually an application
+// with its own UI elements--all rendering and event handling happens via IPC
+// to the renderer process which invoked it.
+
+namespace {
+
+const int kPluginUpdateIntervalMs = 20; // 20ms = 50Hz
+
+void PluginCarbonEventTask() {
+  EventRef theEvent;
+  EventTargetRef theTarget;
+
+  theTarget = GetEventDispatcherTarget();
+
+  // Dispatch any pending events. but do not block if there are no events.
+  while (ReceiveNextEvent(0, NULL, kEventDurationNoWait,
+                          true, &theEvent) == noErr) {
+    SendEventToEventTarget (theEvent, theTarget);
+    ReleaseEvent(theEvent);
+  }
+
+  MessageLoop::current()->PostDelayedTask(FROM_HERE,
+      NewRunnableFunction(PluginCarbonEventTask), kPluginUpdateIntervalMs);
+}
+
+}
+#endif
+
 // main() routine for running as the plugin process.
 int PluginMain(const MainFunctionParams& parameters) {
   // The main thread of the plugin services IO.
   MessageLoopForIO main_message_loop;
   std::wstring app_name = chrome::kBrowserAppName;
   PlatformThread::SetName(WideToASCII(app_name + L"_PluginMain").c_str());
 
   // Initialize the SystemMonitor
   base::SystemMonitor::Start();
 
-#if defined(OS_WIN)
   const CommandLine& parsed_command_line = parameters.command_line_;
 
+#if defined(OS_WIN)
   sandbox::TargetServices* target_services =
       parameters.sandbox_info_.TargetServices();
 
   CoInitialize(NULL);
   DLOG(INFO) << "Started plugin with " <<
     parsed_command_line.command_line_string();
 
   HMODULE sandbox_test_module = NULL;
   bool no_sandbox = parsed_command_line.HasSwitch(switches::kNoSandbox) ||
                     !parsed_command_line.HasSwitch(switches::kSafePlugins);
   if (target_services && !no_sandbox) {
     // The command line might specify a test plugin to load.
     if (parsed_command_line.HasSwitch(switches::kTestSandbox)) {
       std::wstring test_plugin_name =
           parsed_command_line.GetSwitchValue(switches::kTestSandbox);
       sandbox_test_module = LoadLibrary(test_plugin_name.c_str());
       DCHECK(sandbox_test_module);
     }
   }
-
+#endif
   if (parsed_command_line.HasSwitch(switches::kPluginStartupDialog)) {
+#if defined(OS_WIN)
     std::wstring title = chrome::kBrowserAppName;
     title += L" plugin";  // makes attaching to process easier
     win_util::MessageBox(NULL, L"plugin starting...", title,
                          MB_OK | MB_SETFOREGROUND);
-  }
+#elif defined(OS_MACOSX)
+    // TODO(playmobil): In the long term, overriding this flag doesn't seem
+    // right, either use our own flag or open a dialog we can use.
+    // This is just to ease debugging in the interim.
+    LOG(WARNING) << "Plugin ("
+    << getpid()
+    << ") paused waiting for debugger to attach @ pid";
+    pause();
 #else
   NOTIMPLEMENTED() << " non-windows startup, plugin startup dialog etc.";
 #endif
+  }
+
+#if defined(OS_MACOSX)
+  // Spin off a consumer for the native (Carbon) event stream so
+  // that plugin timers, event handlers, etc. will work properly.
+  MessageLoop::current()->PostDelayedTask(FROM_HERE,
+      NewRunnableFunction(PluginCarbonEventTask), kPluginUpdateIntervalMs);
+#endif
 
   {
     ChildProcess plugin_process(new PluginThread());
 #if defined(OS_WIN)
     if (!no_sandbox && target_services)
       target_services->LowerToken();
 
     if (sandbox_test_module) {
       RunRendererTests run_security_tests =
           reinterpret_cast<RunPluginTests>(GetProcAddress(sandbox_test_module,
@@ skipping 13 matching lines @@
 
     MessageLoop::current()->Run();
   }
 
 #if defined(OS_WIN)
   CoUninitialize();
 #endif
 
   return 0;
 }