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// Copyright 2014 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 ScriptForbiddenScope_h
#define ScriptForbiddenScope_h
#include "platform/PlatformExport.h"
#include "wtf/Allocator.h"
#include "wtf/AutoReset.h"
#include "wtf/Optional.h"
namespace blink {
// Scoped disabling of script execution on the main thread,
// and only to be used by the main thread.
class PLATFORM_EXPORT ScriptForbiddenScope final {
STACK_ALLOCATED();
WTF_MAKE_NONCOPYABLE(ScriptForbiddenScope);
public:
ScriptForbiddenScope() { enter(); }
~ScriptForbiddenScope() { exit(); }
class PLATFORM_EXPORT AllowUserAgentScript final {
STACK_ALLOCATED();
WTF_MAKE_NONCOPYABLE(AllowUserAgentScript);
public:
AllowUserAgentScript() {
if (isMainThread())
m_change.emplace(&s_scriptForbiddenCount, 0);
}
~AllowUserAgentScript() {
DCHECK(!isMainThread() || !s_scriptForbiddenCount);
}
private:
Optional<AutoReset<unsigned>> m_change;
};
static void enter() {
DCHECK(isMainThread());
++s_scriptForbiddenCount;
}
static void exit() {
DCHECK(s_scriptForbiddenCount);
--s_scriptForbiddenCount;
}
static bool isScriptForbidden() {
return isMainThread() && s_scriptForbiddenCount;
}
private:
static unsigned s_scriptForbiddenCount;
};
// Scoped disabling of script execution on the main thread,
// if called on the main thread.
//
// No effect when used by from other threads -- simplifies
// call sites that might be used by multiple threads to have
// this scope object perform the is-main-thread check on
// its behalf.
class PLATFORM_EXPORT ScriptForbiddenIfMainThreadScope final {
STACK_ALLOCATED();
WTF_MAKE_NONCOPYABLE(ScriptForbiddenIfMainThreadScope);
public:
ScriptForbiddenIfMainThreadScope() {
m_IsMainThread = isMainThread();
if (m_IsMainThread)
ScriptForbiddenScope::enter();
}
~ScriptForbiddenIfMainThreadScope() {
if (m_IsMainThread)
ScriptForbiddenScope::exit();
}
bool m_IsMainThread;
};
} // namespace blink
#endif // ScriptForbiddenScope_h
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