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BeefMem/gperftools/src/windows/auto_testing_hook.h

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+// Copyright (c) 2010 The Chromium Authors. All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//    * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//    * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//    * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+//
+// Utility for using SideStep with unit tests.
+
+#ifndef CEEE_TESTING_SIDESTEP_AUTO_TESTING_HOOK_H_
+#define CEEE_TESTING_SIDESTEP_AUTO_TESTING_HOOK_H_
+
+#include "base/basictypes.h"
+#include "base/logging.h"
+#include "preamble_patcher.h"
+
+#define SIDESTEP_CHK(x)  CHECK(x)
+#define SIDESTEP_EXPECT_TRUE(x)  SIDESTEP_CHK(x)
+
+namespace sidestep {
+
+// Same trick as common/scope_cleanup.h ScopeGuardImplBase
+class AutoTestingHookBase {
+ public:
+  virtual ~AutoTestingHookBase() {}
+};
+
+// This is the typedef you normally use for the class, e.g.
+//
+// AutoTestingHook hook = MakeTestingHook(TargetFunc, HookTargetFunc);
+//
+// The 'hook' variable will then be destroyed when it goes out of scope.
+//
+// NOTE: You must not hold this type as a member of another class.  Its
+// destructor will not get called.
+typedef const AutoTestingHookBase& AutoTestingHook;
+
+// This is the class you must use when holding a hook as a member of another
+// class, e.g.
+//
+// public:
+//  AutoTestingHookHolder holder_;
+//  MyClass() : my_hook_holder(MakeTestingHookHolder(Target, Hook)) {}
+class AutoTestingHookHolder {
+ public:
+  explicit AutoTestingHookHolder(AutoTestingHookBase* hook) : hook_(hook) {}
+  ~AutoTestingHookHolder() { delete hook_; }
+ private:
+  AutoTestingHookHolder() {}  // disallow
+  AutoTestingHookBase* hook_;
+};
+
+// This class helps patch a function, then unpatch it when the object exits
+// scope, and also maintains the pointer to the original function stub.
+//
+// To enable use of the class without having to explicitly provide the
+// type of the function pointers (and instead only providing it
+// implicitly) we use the same trick as ScopeGuard (see
+// common/scope_cleanup.h) uses, so to create a hook you use the MakeHook
+// function rather than a constructor.
+//
+// NOTE:  This function is only safe for e.g. unit tests and _not_ for
+// production code.  See PreamblePatcher class for details.
+template <typename T>
+class AutoTestingHookImpl : public AutoTestingHookBase {
+ public:
+  static AutoTestingHookImpl<T> MakeTestingHook(T target_function,
+                                                T replacement_function,
+                                                bool do_it) {
+    return AutoTestingHookImpl<T>(target_function, replacement_function, do_it);
+  }
+
+  static AutoTestingHookImpl<T>* MakeTestingHookHolder(T target_function,
+                                                       T replacement_function,
+                                                       bool do_it) {
+    return new AutoTestingHookImpl<T>(target_function,
+                                      replacement_function, do_it);
+  }
+
+  ~AutoTestingHookImpl() {
+    if (did_it_) {
+      SIDESTEP_CHK(SIDESTEP_SUCCESS == PreamblePatcher::Unpatch(
+          (void*)target_function_, (void*)replacement_function_,
+          (void*)original_function_));
+    }
+  }
+
+  // Returns a pointer to the original function.  To use this method you will
+  // have to explicitly create an AutoTestingHookImpl of the specific
+  // function pointer type (i.e. not use the AutoTestingHook typedef).
+  T original_function() {
+    return original_function_;
+  }
+
+ private:
+  AutoTestingHookImpl(T target_function, T replacement_function, bool do_it)
+      : target_function_(target_function),
+        original_function_(NULL),
+        replacement_function_(replacement_function),
+        did_it_(do_it) {
+    if (do_it) {
+      SIDESTEP_CHK(SIDESTEP_SUCCESS == PreamblePatcher::Patch(target_function,
+                                                     replacement_function,
+                                                     &original_function_));
+    }
+  }
+
+  T target_function_;  // always valid
+  T original_function_;  // always valid
+  T replacement_function_;  // always valid
+  bool did_it_;  // Remember if we did it or not...
+};
+
+template <typename T>
+inline AutoTestingHookImpl<T> MakeTestingHook(T target,
+                                              T replacement,
+                                              bool do_it) {
+  return AutoTestingHookImpl<T>::MakeTestingHook(target, replacement, do_it);
+}
+
+template <typename T>
+inline AutoTestingHookImpl<T> MakeTestingHook(T target, T replacement) {
+  return AutoTestingHookImpl<T>::MakeTestingHook(target, replacement, true);
+}
+
+template <typename T>
+inline AutoTestingHookImpl<T>* MakeTestingHookHolder(T target, T replacement) {
+  return AutoTestingHookImpl<T>::MakeTestingHookHolder(target, replacement,
+                                                       true);
+}
+
+};  // namespace sidestep
+
+#endif  // CEEE_TESTING_SIDESTEP_AUTO_TESTING_HOOK_H_