Content: Implement PowerSaveBlocker2 for windows.

content/browser/power_save_blocker_win.cc

 // Copyright (c) 2012 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 "content/browser/power_save_blocker.h"
 
 #include <windows.h>
 
 #include "base/logging.h"
+#include "base/utf_string_conversions.h"
+#include "base/win/scoped_handle.h"
+#include "base/win/windows_version.h"
 #include "content/public/browser/browser_thread.h"
 
 using content::BrowserThread;
 
 // Called only from UI thread.
 // static
 void PowerSaveBlocker::ApplyBlock(PowerSaveBlockerType type) {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
 
   DWORD flags = ES_CONTINUOUS;
 
   switch (type) {
     case kPowerSaveBlockPreventSystemSleep:
       flags |= ES_SYSTEM_REQUIRED;
       break;
     case kPowerSaveBlockPreventDisplaySleep:
       flags |= ES_DISPLAY_REQUIRED;
       break;
     default:
       break;
   }
 
   SetThreadExecutionState(flags);
 }
+
+// TODO(rvargas): Remove after the old interface goes away.
+#define PowerSaveBlocker PowerSaveBlocker2

[Mike Mammarella, 2012/06/05 18:28:49]

Hey, this is clever. I'm going to do the same thing for the Linux version I'm
working on.

+
+namespace {
+
+int g_blocker_count[2];
+
+#if _WIN32_WINNT <= _WIN32_WINNT_WIN7
+POWER_REQUEST_TYPE PowerRequestExecutionRequired =
+    static_cast<POWER_REQUEST_TYPE>(PowerRequestAwayModeRequired + 1);
+#endif
+
+HANDLE CreatePowerRequest(POWER_REQUEST_TYPE type, const std::string& reason) {
+  typedef HANDLE (WINAPI* PowerCreateRequestPtr)(PREASON_CONTEXT);
+  typedef BOOL (WINAPI* PowerSetRequestPtr)(HANDLE, POWER_REQUEST_TYPE);
+
+  if (type == PowerRequestExecutionRequired &&
+      base::win::GetVersion() < base::win::VERSION_WIN8) {
+    return INVALID_HANDLE_VALUE;
+  }
+
+  static PowerCreateRequestPtr PowerCreateRequestFn = NULL;
+  static PowerSetRequestPtr PowerSetRequestFn = NULL;
+
+  if (!PowerCreateRequestFn || !PowerSetRequestFn) {
+    HMODULE module = GetModuleHandle(L"kernel32.dll");
+    PowerCreateRequestFn = reinterpret_cast<PowerCreateRequestPtr>(
+        GetProcAddress(module, "PowerCreateRequest"));
+    PowerSetRequestFn = reinterpret_cast<PowerSetRequestPtr>(
+        GetProcAddress(module, "PowerSetRequest"));
+
+    if (!PowerCreateRequestFn || !PowerSetRequestFn)
+      return INVALID_HANDLE_VALUE;
+  }
+  string16 wide_reason = ASCIIToUTF16(reason);
+  REASON_CONTEXT context = {0};
+  context.Version = POWER_REQUEST_CONTEXT_VERSION;
+  context.Flags = POWER_REQUEST_CONTEXT_SIMPLE_STRING;
+  context.Reason.SimpleReasonString = const_cast<wchar_t*>(wide_reason.c_str());
+
+  base::win::ScopedHandle handle(PowerCreateRequestFn(&context));
+  if (!handle.IsValid())
+    return INVALID_HANDLE_VALUE;
+
+  if (PowerSetRequestFn(handle, type))
+    return handle.Take();
+
+  // Something went wrong.
+  return INVALID_HANDLE_VALUE;
+}
+
+// Takes ownership of the |handle|.
+void DeletePowerRequest(POWER_REQUEST_TYPE type, HANDLE handle) {
+  base::win::ScopedHandle request_handle(handle);
+  if (!request_handle.IsValid())
+    return;
+
+  if (type == PowerRequestExecutionRequired &&
+      base::win::GetVersion() < base::win::VERSION_WIN8) {
+    return;
+  }
+
+  typedef BOOL (WINAPI* PowerClearRequestPtr)(HANDLE, POWER_REQUEST_TYPE);
+  HMODULE module = GetModuleHandle(L"kernel32.dll");
+  PowerClearRequestPtr PowerClearRequestFn =
+      reinterpret_cast<PowerClearRequestPtr>(
+          GetProcAddress(module, "PowerClearRequest"));
+
+  if (!PowerClearRequestFn)
+    return;
+
+  BOOL success = PowerClearRequestFn(request_handle, type);
+  DCHECK(success);
+}
+
+void ApplySimpleBlock(content::PowerSaveBlocker::PowerSaveBlockerType type,
+                      int delta) {
+  g_blocker_count[type] += delta;
+  DCHECK_GE(g_blocker_count[type], 0);
+
+  if (g_blocker_count[type] > 1)
+    return;
+
+  DWORD this_flag = 0;
+  if (type == content::PowerSaveBlocker::kPowerSaveBlockPreventAppSuspension)
+    this_flag |= ES_SYSTEM_REQUIRED;
+  else
+    this_flag |= ES_DISPLAY_REQUIRED;
+
+  DCHECK(this_flag);
+
+  static DWORD flags = ES_CONTINUOUS;
+  if (!g_blocker_count[type])
+    flags &= ~this_flag;
+  else
+    flags |= this_flag;
+
+  SetThreadExecutionState(flags);
+}
+
+}  // namespace.
+
+namespace content {
+
+class PowerSaveBlocker::Delegate
+    : public base::RefCountedThreadSafe<PowerSaveBlocker::Delegate> {
+ public:
+  Delegate(PowerSaveBlockerType type, const std::string& reason)
+      : type_(type), reason_(reason) {}
+  ~Delegate() {}

[Avi (use Gerrit), 2012/06/05 18:48:34]

When I copy this code, I get a style failure:

error: [chromium-style] Classes that are ref-counted should not have public
destructors.

Don't do this either. Make this private.

Of course, that leads to lots of weird cascading errors. Investigating.

[rvargas (doing something else), 2012/06/05 18:58:19]

And this is fixed now.

+
+  // Does the actual work to apply or remove the desired power save block.
+  void ApplyBlock();
+  void RemoveBlock();
+
+  // Returns the equivalent POWER_REQUEST_TYPE for this request.
+  POWER_REQUEST_TYPE RequestType();
+
+ private:
+  PowerSaveBlockerType type_;
+  const std::string reason_;
+  base::win::ScopedHandle handle_;
+};
+
+void PowerSaveBlocker::Delegate::ApplyBlock() {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
+  base::win::Version os_version = base::win::GetVersion();
+  if (os_version < base::win::VERSION_WIN7)
+    return ApplySimpleBlock(type_, 1);
+
+  handle_.Set(CreatePowerRequest(RequestType(), reason_));
+}
+
+void PowerSaveBlocker::Delegate::RemoveBlock() {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
+  base::win::Version os_version = base::win::GetVersion();
+  if (os_version < base::win::VERSION_WIN7)
+    return ApplySimpleBlock(type_, -1);
+
+  DeletePowerRequest(RequestType(), handle_.Take());
+}
+
+POWER_REQUEST_TYPE PowerSaveBlocker::Delegate::RequestType() {
+  if (type_ == kPowerSaveBlockPreventDisplaySleep)
+    return PowerRequestDisplayRequired;
+
+  return PowerRequestExecutionRequired;
+}
+
+PowerSaveBlocker::PowerSaveBlocker(PowerSaveBlockerType type,
+                                   const std::string& reason)
+    : delegate_(new  PowerSaveBlocker::Delegate(type, reason)) {

[Avi (use Gerrit), 2012/06/05 18:11:55]

The only thing I can do: nitpick. Too many spaces between "new" and
"PowerSaveBlocker"

[Mike Mammarella, 2012/06/05 18:28:49]

You don't need the PowerSaveBlocker:: here or below in base::Bind(), although it
won't hurt to keep it.

[rvargas (doing something else), 2012/06/05 18:39:50]

Done.

[rvargas (doing something else), 2012/06/05 18:39:50]

Done.

+  BrowserThread::PostTask(
+      BrowserThread::UI, FROM_HERE,
+      base::Bind(&PowerSaveBlocker::Delegate::ApplyBlock, delegate_));
+}
+
+PowerSaveBlocker::~PowerSaveBlocker(void) {

[Avi (use Gerrit), 2012/06/05 18:11:55]

no void

[rvargas (doing something else), 2012/06/05 18:39:50]

Ouch!. done.

+  BrowserThread::PostTask(
+      BrowserThread::UI, FROM_HERE,
+      base::Bind(&PowerSaveBlocker::Delegate::RemoveBlock, delegate_));
+}
+
+}  // namespace content