Disable system suspend while downloading files on win32.

If the system goes into power-save sleep mode while downloading files,
the download fails. So, prevent sleep mode until the download finishes.

This patch introduces a new RAII class to request that the system's
power-save mode be disabled - PowerSaveBlocker.
This is only implemented for win32; other platforms are stubbed out.

This only partially implements bug 25420 it only attempts to handle the
downloading case.

Patch by Bryan Donlan <bdonlan@gmail.com>

BUG=25420
TEST=Download a large file with the system sleep timeout set to a short interval.
Review URL: http://codereview.chromium.org/287017

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@29873 0039d316-1c4b-4281-b951-d872f2087c98

6 files changed, 140 insertions, 1 deletions

diff --git a/chrome/browser/download/download_file.cc b/chrome/browser/download/download_file.cc
index 7066b5b..b340d00 100644
--- a/chrome/browser/download/download_file.cc
+++ b/chrome/browser/download/download_file.cc
@@ -65,7 +65,8 @@ DownloadFile::DownloadFile(const DownloadCreateInfo* info)
       request_id_(info->request_id),
       bytes_so_far_(0),
       path_renamed_(false),
-      in_progress_(true) {
+      in_progress_(true),
+      dont_sleep_(true) {
 }
 
 DownloadFile::~DownloadFile() {
diff --git a/chrome/browser/download/download_file.h b/chrome/browser/download/download_file.h
index 79195ec..66d3e7c 100644
--- a/chrome/browser/download/download_file.h
+++ b/chrome/browser/download/download_file.h
@@ -51,6 +51,7 @@
 #include "base/lock.h"
 #include "base/ref_counted.h"
 #include "base/timer.h"
+#include "chrome/browser/power_save_blocker.h"
 #include "googleurl/src/gurl.h"
 
 namespace net {
@@ -153,6 +154,9 @@ class DownloadFile {
   // Whether the download is still receiving data.
   bool in_progress_;
 
+  // RAII handle to keep the system from sleeping while we're downloading.
+  PowerSaveBlocker dont_sleep_;
+
   DISALLOW_COPY_AND_ASSIGN(DownloadFile);
 };
 
diff --git a/chrome/browser/power_save_blocker.h b/chrome/browser/power_save_blocker.h
new file mode 100644
index 0000000..f362915
--- /dev/null
+++ b/chrome/browser/power_save_blocker.h
@@ -0,0 +1,42 @@
+// Copyright (c) 2009 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.
+
+#ifndef CHROME_BROWSER_POWER_SAVE_BLOCKER_H_
+#define CHROME_BROWSER_POWER_SAVE_BLOCKER_H_
+
+#include "base/basictypes.h"
+
+// A RAII-style class to block the system from entering low-power
+// (sleep) mode.
+class PowerSaveBlocker {
+ public:
+  explicit PowerSaveBlocker(bool enabled);
+  ~PowerSaveBlocker();
+
+  bool enabled() const { return enabled_; }
+
+  // Puts the sleep mode block into effect.
+  void Enable();
+  // Disables the sleep block.
+  void Disable();
+
+ private:
+  // Platform-specific function called when enable state is changed.
+  // Guarenteed to be called only from the UI thread.
+  static void ApplyBlock(bool blocked);
+
+  // Called only from UI thread.
+  static void AdjustBlockCount(int delta);
+
+  // Invokes AdjustBlockCount on the UI thread.
+  static void PostAdjustBlockCount(int delta);
+
+  bool enabled_;
+
+  static int blocker_count_;
+
+  DISALLOW_COPY_AND_ASSIGN(PowerSaveBlocker);
+};
+
+#endif  // CHROME_BROWSER_POWER_SAVE_BLOCKER_H_
diff --git a/chrome/browser/power_save_blocker_common.cc b/chrome/browser/power_save_blocker_common.cc
new file mode 100644
index 0000000..b6ff2ac
--- /dev/null
+++ b/chrome/browser/power_save_blocker_common.cc
@@ -0,0 +1,58 @@
+// Copyright (c) 2009 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/browser/power_save_blocker.h"
+#include "chrome/browser/chrome_thread.h"
+
+// Accessed only from the UI thread.
+int PowerSaveBlocker::blocker_count_ = 0;
+
+PowerSaveBlocker::PowerSaveBlocker(bool enable) : enabled_(false) {
+  if (enable)
+    Enable();
+}
+
+PowerSaveBlocker::~PowerSaveBlocker(void) {
+  Disable();
+}
+
+void PowerSaveBlocker::Enable() {
+  if (enabled_)
+    return;
+
+  enabled_ = true;
+  PostAdjustBlockCount(1);
+}
+
+void PowerSaveBlocker::Disable() {
+  if (!enabled_)
+    return;
+
+  enabled_ = false;
+  PostAdjustBlockCount(-1);
+}
+
+
+void PowerSaveBlocker::PostAdjustBlockCount(int delta) {
+  MessageLoop *ml = ChromeThread::GetMessageLoop(ChromeThread::UI);
+
+  ml->PostTask(FROM_HERE,
+      NewRunnableFunction(&PowerSaveBlocker::AdjustBlockCount, delta));
+}
+
+// Called only from UI thread.
+void PowerSaveBlocker::AdjustBlockCount(int delta) {
+  DCHECK(ChromeThread::CurrentlyOn(ChromeThread::UI));
+
+  bool was_blocking = (blocker_count_ != 0);
+
+  blocker_count_ += delta;
+
+  bool is_blocking = (blocker_count_ != 0);
+
+  DCHECK_GE(blocker_count_, 0);
+
+  if (is_blocking != was_blocking)
+    ApplyBlock(is_blocking);
+}
diff --git a/chrome/browser/power_save_blocker_stub.cc b/chrome/browser/power_save_blocker_stub.cc
new file mode 100644
index 0000000..3c31f14
--- /dev/null
+++ b/chrome/browser/power_save_blocker_stub.cc
@@ -0,0 +1,13 @@
+// Copyright (c) 2009 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/browser/power_save_blocker.h"
+
+#include "base/logging.h"
+
+// Default, stub implementation, for platforms that don't have their own yet.
+
+void PowerSaveBlocker::ApplyBlock(bool blocking) {
+  NOTIMPLEMENTED();
+}
diff --git a/chrome/browser/power_save_blocker_win.cc b/chrome/browser/power_save_blocker_win.cc
new file mode 100644
index 0000000..f7d3d8c
--- /dev/null
+++ b/chrome/browser/power_save_blocker_win.cc
@@ -0,0 +1,21 @@
+// Copyright (c) 2009 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/browser/power_save_blocker.h"
+
+#include <windows.h>
+
+#include "chrome/browser/chrome_thread.h"
+
+// Runs on UI thread only.
+void PowerSaveBlocker::ApplyBlock(bool blocking) {
+  DCHECK(ChromeThread::CurrentlyOn(ChromeThread::UI));
+
+  DWORD flags = ES_CONTINUOUS;
+
+  if (blocking)
+    flags |= ES_SYSTEM_REQUIRED;
+
+  SetThreadExecutionState(flags);
+}