Mac-specific CFRunLoop-based MessagePump implementation

base/message_pump_mac.mm

+// Copyright (c) 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 "base/message_pump_mac.h"
+
+#import <AppKit/AppKit.h>
+#import <Foundation/Foundation.h>
+#include <float.h>
+
+namespace {
+
+void NoOp(void* info) {
+}
+
+}  // namespace
+
+namespace base {
+
+// Must be called on the run loop thread.
+MessagePumpCFRunLoopBase::MessagePumpCFRunLoopBase()
+    : delegate_(NULL) {
+  run_loop_ = CFRunLoopGetCurrent();
+  CFRetain(run_loop_);
+
+  // Set a repeating timer with a preposterous firing time and interval.  The
+  // timer will effectively never fire as-is.  The firing time will be adjusted
+  // as needed when ScheduleDelayedWork is called.
+  CFRunLoopTimerContext timer_context = CFRunLoopTimerContext();
+  timer_context.info = this;
+  delayed_work_timer_ = CFRunLoopTimerCreate(NULL,     // allocator
+                                             DBL_MAX,  // fire time
+                                             DBL_MAX,  // interval
+                                             0,        // flags (ignored)
+                                             0,        // priority (ignored)
+                                             RunDelayedWorkTimer,
+                                             &timer_context);
+  CFRunLoopAddTimer(run_loop_, delayed_work_timer_, kCFRunLoopCommonModes);
+
+  CFRunLoopSourceContext source_context = CFRunLoopSourceContext();
+  source_context.info = this;
+  source_context.perform = RunWork;
+  work_source_ = CFRunLoopSourceCreate(NULL,  // allocator
+                                       0,     // priority
+                                       &source_context);
+  CFRunLoopAddSource(run_loop_, work_source_, kCFRunLoopCommonModes);
+
+  source_context.perform = RunDelayedWork;
+  delayed_work_source_ = CFRunLoopSourceCreate(NULL,  // allocator
+                                               1,     // priority
+                                               &source_context);
+  CFRunLoopAddSource(run_loop_, delayed_work_source_, kCFRunLoopCommonModes);
+
+  CFRunLoopObserverContext observer_context = CFRunLoopObserverContext();
+  observer_context.info = this;
+  idle_work_observer_ = CFRunLoopObserverCreate(NULL,  // allocator
+                                                kCFRunLoopBeforeWaiting,
+                                                true,  // repeat
+                                                0,     // priority
+                                                RunIdleWork,
+                                                &observer_context);
+  CFRunLoopAddObserver(run_loop_, idle_work_observer_, kCFRunLoopCommonModes);
+}
+
+// Ideally called on the run loop thread.
+MessagePumpCFRunLoopBase::~MessagePumpCFRunLoopBase() {
+  CFRunLoopRemoveObserver(run_loop_, idle_work_observer_,
+                          kCFRunLoopCommonModes);
+  CFRelease(idle_work_observer_);
+
+  CFRunLoopRemoveSource(run_loop_, delayed_work_source_, kCFRunLoopCommonModes);
+  CFRelease(delayed_work_source_);
+
+  CFRunLoopRemoveSource(run_loop_, work_source_, kCFRunLoopCommonModes);
+  CFRelease(work_source_);
+
+  CFRunLoopRemoveTimer(run_loop_, delayed_work_timer_, kCFRunLoopCommonModes);
+  CFRelease(delayed_work_timer_);
+
+  CFRelease(run_loop_);
+}
+
+// Must be called on the run loop thread.
+void MessagePumpCFRunLoopBase::Run(Delegate* delegate) {
+  Delegate* last_delegate = delegate_;
+  delegate_ = delegate;
+
+  DoRun(delegate);
+
+  delegate_ = last_delegate;
+}
+
+// May be called on any thread.
+void MessagePumpCFRunLoopBase::ScheduleWork() {
+  CFRunLoopSourceSignal(work_source_);
+  CFRunLoopWakeUp(run_loop_);
+}
+
+// Must be called on the run loop thread.
+void MessagePumpCFRunLoopBase::ScheduleDelayedWork(
+    const Time& delayed_work_time) {
+  Time::Exploded exploded;
+  delayed_work_time.UTCExplode(&exploded);
+  double seconds = exploded.second +
+                   (static_cast<double>((delayed_work_time.ToInternalValue()) %
+                                        Time::kMicrosecondsPerSecond) /
+                    Time::kMicrosecondsPerSecond);
+  CFGregorianDate gregorian = {
+    exploded.year,
+    exploded.month,
+    exploded.day_of_month,
+    exploded.hour,
+    exploded.minute,
+    seconds
+  };
+  CFAbsoluteTime fire_time = CFGregorianDateGetAbsoluteTime(gregorian, NULL);
+
+  CFRunLoopTimerSetNextFireDate(delayed_work_timer_, fire_time);
+}
+
+// Called from the run loop.
+// static
+void MessagePumpCFRunLoopBase::RunDelayedWorkTimer(CFRunLoopTimerRef timer,
+                                                   void* info) {
+  MessagePumpCFRunLoop* self = static_cast<MessagePumpCFRunLoop*>(info);
+
+  // CFRunLoopTimers fire outside of the priority scheme for CFRunLoopSources.
+  // In order to establish the proper priority where delegate_->DoDelayedWork
+  // can only be called if delegate_->DoWork returns false, the timer used
+  // to schedule delayed work must signal a CFRunLoopSource set at a lower
+  // priority than the one used for delegate_->DoWork.
+  CFRunLoopSourceSignal(self->delayed_work_source_);
+}
+
+// Called from the run loop.
+// static
+void MessagePumpCFRunLoopBase::RunWork(void* info) {
+  MessagePumpCFRunLoop* self = static_cast<MessagePumpCFRunLoop*>(info);
+
+  // Call DoWork once, and if something was done, arrange to come back here
+  // again as long as the loop is still running.
+  if (self->delegate_->DoWork()) {
+    CFRunLoopSourceSignal(self->work_source_);
+  }
+}
+
+// Called from the run loop.
+// static
+void MessagePumpCFRunLoopBase::RunDelayedWork(void* info) {
+  MessagePumpCFRunLoop* self = static_cast<MessagePumpCFRunLoop*>(info);
+
+  Time next_time;
+  self->delegate_->DoDelayedWork(&next_time);
+  if (!next_time.is_null()) {
+    TimeDelta delay = next_time - Time::Now();
+    if (delay > TimeDelta()) {
+      // There's more delayed work to be done in the future.
+      self->ScheduleDelayedWork(next_time);
+    } else {
+      // There's more delayed work to be done, and its time is in the past.
+      // Arrange to come back here directly as long as the loop is still
+      // running.
+      CFRunLoopSourceSignal(self->delayed_work_source_);
+    }
+  }
+}
+
+// Called from the run loop.
+// static
+void MessagePumpCFRunLoopBase::RunIdleWork(CFRunLoopObserverRef observer,
+                                           CFRunLoopActivity activity,
+                                           void* info) {
+  MessagePumpCFRunLoop* self = static_cast<MessagePumpCFRunLoop*>(info);
+
+  if (self->delegate_->DoIdleWork()) {
+    // If idle work was done, don't let the loop go to sleep.  More idle work
+    // might be waiting.
+    CFRunLoopWakeUp(self->run_loop_);
+  }
+}
+
+// Must be called on the run loop thread.
+MessagePumpCFRunLoop::MessagePumpCFRunLoop()
+    : nesting_level_(0),
+      innermost_quittable_(0),
+      quit_pending_(false) {
+  CFRunLoopObserverContext observer_context = CFRunLoopObserverContext();
+  observer_context.info = this;
+  enter_exit_observer_ = CFRunLoopObserverCreate(NULL,  // allocator
+                                                 kCFRunLoopEntry |
+                                                     kCFRunLoopExit,
+                                                 true,  // repeat
+                                                 0,     // priority
+                                                 EnterExitRunLoop,
+                                                 &observer_context);
+  CFRunLoopAddObserver(run_loop_, enter_exit_observer_, kCFRunLoopCommonModes);
+}
+
+// Ideally called on the run loop thread.  If other CFRunLoopRun loops were
+// running lower on the run loop thread's stack when this object was created,
+// the same number of CFRunLoopRun loops must be running when this object is
+// destroyed.
+MessagePumpCFRunLoop::~MessagePumpCFRunLoop() {
+  CFRunLoopRemoveObserver(run_loop_, enter_exit_observer_,
+                          kCFRunLoopCommonModes);
+  CFRelease(enter_exit_observer_);
+}
+
+// Called by CFRunLoopBase::DoRun.  If other CFRunLoopRun loops were running
+// lower on the run loop thread's stack when this object was created, the same
+// number of CFRunLoopRun loops must be running for the outermost call to Run.
+// Run/DoRun are reentrant after that point.
+void MessagePumpCFRunLoop::DoRun(Delegate* delegate) {
+  // nesting_level_ will be incremented in EnterExitRunLoop, so set
+  // innermost_quittable_ accordingly.
+  int last_innermost_quittable = innermost_quittable_;
+  innermost_quittable_ = nesting_level_ + 1;
+
+  CFRunLoopRun();
+
+  // Restore the previous state of the object.
+  innermost_quittable_ = last_innermost_quittable;
+}
+
+// Must be called on the run loop thread.
+void MessagePumpCFRunLoop::Quit() {
+  // Stop the innermost run loop managed by this MessagePumpCFRunLoop object.
+  if (nesting_level_ == innermost_quittable_) {
+    // This object is running the innermost loop, just stop it.
+    CFRunLoopStop(run_loop_);
+  } else {
+    // There's another loop running inside the loop managed by this object.
+    // In other words, someone else called CFRunLoopRun on the same thread,
+    // higher on the stack than our highest Run call.  Don't preempt other
+    // run loops, just mark the object to quit our innermost run loop as soon
+    // as the other inner loops we don't manage are done.
+    quit_pending_ = true;
+  }
+}
+
+// Called from the run loop.
+// static
+void MessagePumpCFRunLoop::EnterExitRunLoop(CFRunLoopObserverRef observer,
+                                            CFRunLoopActivity activity,
+                                            void* info) {
+  MessagePumpCFRunLoop* self = static_cast<MessagePumpCFRunLoop*>(info);
+
+  switch (activity) {
+    case kCFRunLoopEntry:
+      // If the run loop was entered by a call to Run, this will properly
+      // balance the decrement done in Run before entering the loop.
+      ++self->nesting_level_;
+      break;
+    case kCFRunLoopExit:
+      if (--self->nesting_level_ == self->innermost_quittable_ &&
+          self->quit_pending_) {
+        // Quit was called while loops other than those managed by this object
+        // were running further inside a run loop managed by this object.  Now
+        // that all unmanaged inner run loops are gone, stop the loop running
+        // just inside Run.
+        CFRunLoopStop(self->run_loop_);
+        self->quit_pending_ = false;
+      }
+      break;
+    default:
+      break;
+  }
+}
+
+MessagePumpNSRunLoop::MessagePumpNSRunLoop()
+    : keep_running_(true) {
+  CFRunLoopSourceContext source_context = CFRunLoopSourceContext();
+  source_context.perform = NoOp;
+  quit_source_ = CFRunLoopSourceCreate(NULL,  // allocator
+                                       0,     // priority
+                                       &source_context);
+  CFRunLoopAddSource(run_loop_, quit_source_, kCFRunLoopCommonModes);
+}
+
+MessagePumpNSRunLoop::~MessagePumpNSRunLoop() {
+  CFRunLoopRemoveSource(run_loop_, quit_source_, kCFRunLoopCommonModes);
+  CFRelease(quit_source_);
+}
+
+void MessagePumpNSRunLoop::DoRun(Delegate* delegate) {
+  while (keep_running_) {
+    // NSRunLoop manages autorelease pools itself.
+    [[NSRunLoop currentRunLoop] runMode:NSDefaultRunLoopMode
+                             beforeDate:[NSDate distantFuture]];
+  }
+
+  keep_running_ = true;
+}
+
+void MessagePumpNSRunLoop::Quit() {
+  keep_running_ = false;
+  CFRunLoopSourceSignal(quit_source_);
+  CFRunLoopWakeUp(run_loop_);
+}
+
+MessagePumpNSApplication::MessagePumpNSApplication()
+    : keep_running_(true),
+      running_own_loop_(false) {
+}
+
+void MessagePumpNSApplication::DoRun(Delegate* delegate) {
+  bool last_running_own_loop_ = running_own_loop_;
+
+  [NSApplication sharedApplication];
+
+  if (![NSApp isRunning]) {
+    running_own_loop_ = false;
+    // NSApplication manages autorelease pools itself when run this way.
+    [NSApp run];
+  } else {
+    running_own_loop_ = true;
+    while (keep_running_) {
+      NSAutoreleasePool* autorelease_pool = [[NSAutoreleasePool alloc] init];
+      NSEvent* event = [NSApp nextEventMatchingMask:NSAnyEventMask
+                                          untilDate:[NSDate distantFuture]
+                                             inMode:NSDefaultRunLoopMode
+                                            dequeue:YES];
+      if (event) {
+        [NSApp sendEvent:event];
+      }
+      [autorelease_pool drain];
+    }
+    keep_running_ = true;
+  }
+
+  running_own_loop_ = last_running_own_loop_;
+}
+
+void MessagePumpNSApplication::Quit() {
+  if (!running_own_loop_) {
+    [NSApp stop:nil];
+  } else {
+    keep_running_ = false;
+  }
+
+  // Send a fake event to wake the loop up.
+  [NSApp postEvent:[NSEvent otherEventWithType:NSApplicationDefined
+                                      location:NSMakePoint(0,0)
+                                 modifierFlags:0
+                                     timestamp:0
+                                  windowNumber:0
+                                       context:NULL
+                                       subtype:0
+                                         data1:0
+                                         data2:0]
+           atStart:NO];
+}
+
+// static
+MessagePump* MessagePumpMac::Create() {
+  if ([NSThread isMainThread]) {
+    return new MessagePumpNSApplication;
+  }
+
+  return new MessagePumpNSRunLoop;
+}
+
+}  // namespace base