Adding upstream version 124.0.1.upstream/124.0.1

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 291 insertions, 0 deletions

diff --git a/ipc/chromium/src/base/message_pump_glib.cc b/ipc/chromium/src/base/message_pump_glib.cc
new file mode 100644
index 0000000000..7f3dc0f965
--- /dev/null
+++ b/ipc/chromium/src/base/message_pump_glib.cc
@@ -0,0 +1,291 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+// 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_glib.h"
+
+#include <unistd.h>
+#include <math.h>
+
+#include <gtk/gtk.h>
+#include <glib.h>
+
+#include "base/eintr_wrapper.h"
+#include "base/logging.h"
+#include "base/platform_thread.h"
+
+namespace {
+
+// Return a timeout suitable for the glib loop, -1 to block forever,
+// 0 to return right away, or a timeout in milliseconds from now.
+int GetTimeIntervalMilliseconds(const base::TimeTicks& from) {
+  if (from.is_null()) return -1;
+
+  // Be careful here.  TimeDelta has a precision of microseconds, but we want a
+  // value in milliseconds.  If there are 5.5ms left, should the delay be 5 or
+  // 6?  It should be 6 to avoid executing delayed work too early.
+  int delay =
+      static_cast<int>(ceil((from - base::TimeTicks::Now()).InMillisecondsF()));
+
+  // If this value is negative, then we need to run delayed work soon.
+  return delay < 0 ? 0 : delay;
+}
+
+// A brief refresher on GLib:
+//     GLib sources have four callbacks: Prepare, Check, Dispatch and Finalize.
+// On each iteration of the GLib pump, it calls each source's Prepare function.
+// This function should return TRUE if it wants GLib to call its Dispatch, and
+// FALSE otherwise.  It can also set a timeout in this case for the next time
+// Prepare should be called again (it may be called sooner).
+//     After the Prepare calls, GLib does a poll to check for events from the
+// system.  File descriptors can be attached to the sources.  The poll may block
+// if none of the Prepare calls returned TRUE.  It will block indefinitely, or
+// by the minimum time returned by a source in Prepare.
+//     After the poll, GLib calls Check for each source that returned FALSE
+// from Prepare.  The return value of Check has the same meaning as for Prepare,
+// making Check a second chance to tell GLib we are ready for Dispatch.
+//     Finally, GLib calls Dispatch for each source that is ready.  If Dispatch
+// returns FALSE, GLib will destroy the source.  Dispatch calls may be recursive
+// (i.e., you can call Run from them), but Prepare and Check cannot.
+//     Finalize is called when the source is destroyed.
+// NOTE: It is common for subsytems to want to process pending events while
+// doing intensive work, for example the flash plugin. They usually use the
+// following pattern (recommended by the GTK docs):
+// while (gtk_events_pending()) {
+//   gtk_main_iteration();
+// }
+//
+// gtk_events_pending just calls g_main_context_pending, which does the
+// following:
+// - Call prepare on all the sources.
+// - Do the poll with a timeout of 0 (not blocking).
+// - Call check on all the sources.
+// - *Does not* call dispatch on the sources.
+// - Return true if any of prepare() or check() returned true.
+//
+// gtk_main_iteration just calls g_main_context_iteration, which does the whole
+// thing, respecting the timeout for the poll (and block, although it is
+// expected not to if gtk_events_pending returned true), and call dispatch.
+//
+// Thus it is important to only return true from prepare or check if we
+// actually have events or work to do. We also need to make sure we keep
+// internal state consistent so that if prepare/check return true when called
+// from gtk_events_pending, they will still return true when called right
+// after, from gtk_main_iteration.
+//
+// For the GLib pump we try to follow the Windows UI pump model:
+// - Whenever we receive a wakeup event or the timer for delayed work expires,
+// we run DoWork and/or DoDelayedWork. That part will also run in the other
+// event pumps.
+// - We also run DoWork, DoDelayedWork, and possibly DoIdleWork in the main
+// loop, around event handling.
+
+struct WorkSource : public GSource {
+  base::MessagePumpForUI* pump;
+};
+
+gboolean WorkSourcePrepare(GSource* source, gint* timeout_ms) {
+  *timeout_ms = static_cast<WorkSource*>(source)->pump->HandlePrepare();
+  // We always return FALSE, so that our timeout is honored.  If we were
+  // to return TRUE, the timeout would be considered to be 0 and the poll
+  // would never block.  Once the poll is finished, Check will be called.
+  return FALSE;
+}
+
+gboolean WorkSourceCheck(GSource* source) {
+  // Only return TRUE if Dispatch should be called.
+  return static_cast<WorkSource*>(source)->pump->HandleCheck();
+}
+
+gboolean WorkSourceDispatch(GSource* source, GSourceFunc unused_func,
+                            gpointer unused_data) {
+  static_cast<WorkSource*>(source)->pump->HandleDispatch();
+  // Always return TRUE so our source stays registered.
+  return TRUE;
+}
+
+// I wish these could be const, but g_source_new wants non-const.
+GSourceFuncs WorkSourceFuncs = {WorkSourcePrepare, WorkSourceCheck,
+                                WorkSourceDispatch, NULL};
+
+}  // namespace
+
+namespace base {
+
+MessagePumpForUI::MessagePumpForUI()
+    : state_(NULL),
+      context_(g_main_context_default()),
+      wakeup_gpollfd_(new GPollFD),
+      pipe_full_(false) {
+  // Create our wakeup pipe, which is used to flag when work was scheduled.
+  int fds[2];
+  CHECK(pipe(fds) == 0);
+  wakeup_pipe_read_ = fds[0];
+  wakeup_pipe_write_ = fds[1];
+  wakeup_gpollfd_->fd = wakeup_pipe_read_;
+  wakeup_gpollfd_->events = G_IO_IN;
+
+  work_source_ = g_source_new(&WorkSourceFuncs, sizeof(WorkSource));
+  static_cast<WorkSource*>(work_source_)->pump = this;
+  g_source_add_poll(work_source_, wakeup_gpollfd_.get());
+  // Use a low priority so that we let other events in the queue go first.
+  g_source_set_priority(work_source_, G_PRIORITY_DEFAULT_IDLE);
+  // This is needed to allow Run calls inside Dispatch.
+  g_source_set_can_recurse(work_source_, TRUE);
+  g_source_attach(work_source_, context_);
+}
+
+MessagePumpForUI::~MessagePumpForUI() {
+  gdk_event_handler_set(reinterpret_cast<GdkEventFunc>(gtk_main_do_event), this,
+                        NULL);
+  g_source_destroy(work_source_);
+  g_source_unref(work_source_);
+  close(wakeup_pipe_read_);
+  close(wakeup_pipe_write_);
+}
+
+void MessagePumpForUI::Run(Delegate* delegate) {
+#ifndef NDEBUG
+  // Make sure we only run this on one thread.  GTK only has one message pump
+  // so we can only have one UI loop per process.
+  static PlatformThreadId thread_id = PlatformThread::CurrentId();
+  DCHECK(thread_id == PlatformThread::CurrentId())
+      << "Running MessagePumpForUI on two different threads; "
+         "this is unsupported by GLib!";
+#endif
+
+  RunState state;
+  state.delegate = delegate;
+  state.should_quit = false;
+  state.run_depth = state_ ? state_->run_depth + 1 : 1;
+  state.has_work = false;
+
+  RunState* previous_state = state_;
+  state_ = &state;
+
+  // We really only do a single task for each iteration of the loop.  If we
+  // have done something, assume there is likely something more to do.  This
+  // will mean that we don't block on the message pump until there was nothing
+  // more to do.  We also set this to true to make sure not to block on the
+  // first iteration of the loop, so RunAllPending() works correctly.
+  bool more_work_is_plausible = true;
+
+  // We run our own loop instead of using g_main_loop_quit in one of the
+  // callbacks.  This is so we only quit our own loops, and we don't quit
+  // nested loops run by others.  TODO(deanm): Is this what we want?
+  for (;;) {
+    // Don't block if we think we have more work to do.
+    bool block = !more_work_is_plausible;
+
+    // g_main_context_iteration returns true if events have been dispatched.
+    more_work_is_plausible = g_main_context_iteration(context_, block);
+    if (state_->should_quit) break;
+
+    more_work_is_plausible |= state_->delegate->DoWork();
+    if (state_->should_quit) break;
+
+    more_work_is_plausible |=
+        state_->delegate->DoDelayedWork(&delayed_work_time_);
+    if (state_->should_quit) break;
+
+    if (more_work_is_plausible) continue;
+
+    more_work_is_plausible = state_->delegate->DoIdleWork();
+    if (state_->should_quit) break;
+  }
+
+  state_ = previous_state;
+}
+
+// Return the timeout we want passed to poll.
+int MessagePumpForUI::HandlePrepare() {
+  // We know we have work, but we haven't called HandleDispatch yet. Don't let
+  // the pump block so that we can do some processing.
+  if (state_ &&  // state_ may be null during tests.
+      state_->has_work)
+    return 0;
+
+  // We don't think we have work to do, but make sure not to block
+  // longer than the next time we need to run delayed work.
+  return GetTimeIntervalMilliseconds(delayed_work_time_);
+}
+
+bool MessagePumpForUI::HandleCheck() {
+  if (!state_)  // state_ may be null during tests.
+    return false;
+
+  // We should only ever have a single message on the wakeup pipe since we only
+  // write to the pipe when pipe_full_ is false. The glib poll will tell us
+  // whether there was data, so this read shouldn't block.
+  if (wakeup_gpollfd_->revents & G_IO_IN) {
+    pipe_full_ = false;
+
+    char msg;
+    if (HANDLE_EINTR(read(wakeup_pipe_read_, &msg, 1)) != 1 || msg != '!') {
+      NOTREACHED() << "Error reading from the wakeup pipe.";
+    }
+    // Since we ate the message, we need to record that we have more work,
+    // because HandleCheck() may be called without HandleDispatch being called
+    // afterwards.
+    state_->has_work = true;
+  }
+
+  if (state_->has_work) return true;
+
+  if (GetTimeIntervalMilliseconds(delayed_work_time_) == 0) {
+    // The timer has expired. That condition will stay true until we process
+    // that delayed work, so we don't need to record this differently.
+    return true;
+  }
+
+  return false;
+}
+
+void MessagePumpForUI::HandleDispatch() {
+  state_->has_work = false;
+  if (state_->delegate->DoWork()) {
+    // NOTE: on Windows at this point we would call ScheduleWork (see
+    // MessagePumpForUI::HandleWorkMessage in message_pump_win.cc). But here,
+    // instead of posting a message on the wakeup pipe, we can avoid the
+    // syscalls and just signal that we have more work.
+    state_->has_work = true;
+  }
+
+  if (state_->should_quit) return;
+
+  state_->delegate->DoDelayedWork(&delayed_work_time_);
+}
+
+void MessagePumpForUI::Quit() {
+  if (state_) {
+    state_->should_quit = true;
+  } else {
+    NOTREACHED() << "Quit called outside Run!";
+  }
+}
+
+void MessagePumpForUI::ScheduleWork() {
+  bool was_full = pipe_full_.exchange(true);
+  if (was_full) {
+    return;
+  }
+
+  // This can be called on any thread, so we don't want to touch any state
+  // variables as we would then need locks all over.  This ensures that if
+  // we are sleeping in a poll that we will wake up.
+  char msg = '!';
+  if (HANDLE_EINTR(write(wakeup_pipe_write_, &msg, 1)) != 1) {
+    NOTREACHED() << "Could not write to the UI message loop wakeup pipe!";
+  }
+}
+
+void MessagePumpForUI::ScheduleDelayedWork(const TimeTicks& delayed_work_time) {
+  // We need to wake up the loop in case the poll timeout needs to be
+  // adjusted.  This will cause us to try to do work, but that's ok.
+  delayed_work_time_ = delayed_work_time;
+  ScheduleWork();
+}
+
+}  // namespace base