gecko-dev/dom/plugins/ipc/PluginWidgetChild.cpp
Nicholas Nethercote 34dcc7b852 Bug 1299384 - Use MOZ_MUST_USE with NS_warn_if_impl(). r=erahm.
This change avoids lots of false positives for Coverity's CHECKED_RETURN
warning, caused by NS_WARN_IF's current use in both statement-style and
expression-style.

In the case where the code within the NS_WARN_IF has side-effects, I made the
following change.

> NS_WARN_IF(NS_FAILED(FunctionWithSideEffects()));
> -->
> Unused << NS_WARN_IF(NS_FAILED(FunctionWithSideEffects()));

In the case where the code within the NS_WARN_IF lacks side-effects, I made the
following change.

> NS_WARN_IF(!condWithoutSideEffects);
> -->
> NS_WARNING_ASSERTION(condWithoutSideEffects, "msg");

This has two improvements.
- The condition is not evaluated in non-debug builds.
- The sense of the condition is inverted to the familiar "this condition should
  be true" sense used in assertions.

A common variation on the side-effect-free case is the following.

> nsresult rv = Fn();
> NS_WARN_IF_(NS_FAILED(rv));
> -->
> DebugOnly<nsresult rv> = Fn();
> NS_WARNING_ASSERTION(NS_SUCCEEDED(rv), "Fn failed");

--HG--
extra : rebase_source : 58788245021096efa8372a9dc1d597a611d45611
2016-09-02 17:12:24 +10:00

91 lines
2.1 KiB
C++

/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
#include "mozilla/plugins/PluginWidgetChild.h"
#include "mozilla/dom/TabChild.h"
#include "mozilla/plugins/PluginWidgetParent.h"
#include "PluginWidgetProxy.h"
#include "mozilla/Unused.h"
#include "mozilla/DebugOnly.h"
#include "nsDebug.h"
#if defined(XP_WIN)
#include "mozilla/plugins/PluginInstanceParent.h"
#endif
#define PWLOG(...)
//#define PWLOG(...) printf_stderr(__VA_ARGS__)
namespace mozilla {
namespace plugins {
PluginWidgetChild::PluginWidgetChild() :
mWidget(nullptr)
{
PWLOG("PluginWidgetChild::PluginWidgetChild()\n");
MOZ_COUNT_CTOR(PluginWidgetChild);
}
PluginWidgetChild::~PluginWidgetChild()
{
PWLOG("PluginWidgetChild::~PluginWidgetChild()\n");
MOZ_COUNT_DTOR(PluginWidgetChild);
}
bool
PluginWidgetChild::RecvSetScrollCaptureId(const uint64_t& aScrollCaptureId,
const uintptr_t& aPluginInstanceId)
{
#if defined(XP_WIN)
PluginInstanceParent* instance =
PluginInstanceParent::LookupPluginInstanceByID(aPluginInstanceId);
if (instance) {
Unused << NS_WARN_IF(NS_FAILED(instance->SetScrollCaptureId(aScrollCaptureId)));
}
return true;
#else
MOZ_ASSERT_UNREACHABLE(
"PluginWidgetChild::RecvSetScrollCaptureId calls not expected.");
return false;
#endif
}
// Called by the proxy widget when it is destroyed by layout. Only gets
// called once.
void
PluginWidgetChild::ProxyShutdown()
{
PWLOG("PluginWidgetChild::ProxyShutdown()\n");
if (mWidget) {
mWidget = nullptr;
auto tab = static_cast<mozilla::dom::TabChild*>(Manager());
if (!tab->IsDestroyed()) {
Unused << Send__delete__(this);
}
}
}
void
PluginWidgetChild::KillWidget()
{
PWLOG("PluginWidgetChild::KillWidget()\n");
if (mWidget) {
mWidget->ChannelDestroyed();
}
mWidget = nullptr;
}
void
PluginWidgetChild::ActorDestroy(ActorDestroyReason aWhy)
{
PWLOG("PluginWidgetChild::ActorDestroy(%d)\n", aWhy);
KillWidget();
}
} // namespace plugins
} // namespace mozilla