third_party/tcmalloc/chromium/src/windows/auto_testing_hook.h

   1 // Copyright (c) 2010 The Chromium Authors. All rights reserved.
   2 //
   3 // Redistribution and use in source and binary forms, with or without
   4 // modification, are permitted provided that the following conditions are
   5 // met:
   6 //
   7 //    * Redistributions of source code must retain the above copyright
   8 // notice, this list of conditions and the following disclaimer.
   9 //    * Redistributions in binary form must reproduce the above
  10 // copyright notice, this list of conditions and the following disclaimer
  11 // in the documentation and/or other materials provided with the
  12 // distribution.
  13 //    * Neither the name of Google Inc. nor the names of its
  14 // contributors may be used to endorse or promote products derived from
  15 // this software without specific prior written permission.
  16 //
  17 // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  18 // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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  20 // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  21 // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  22 // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  23 // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  24 // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  25 // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  26 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  27 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  28 //
  29 // Utility for using SideStep with unit tests.
  30
  31 #ifndef CEEE_TESTING_SIDESTEP_AUTO_TESTING_HOOK_H_
  32 #define CEEE_TESTING_SIDESTEP_AUTO_TESTING_HOOK_H_
  33
  34 #include "base/basictypes.h"
  35 #include "base/logging.h"
  36 #include "preamble_patcher.h"
  37
  38 #define SIDESTEP_CHK(x)  CHECK(x)
  39 #define SIDESTEP_EXPECT_TRUE(x)  SIDESTEP_CHK(x)
  40
  41 namespace sidestep {
  42
  43 // Same trick as common/scope_cleanup.h ScopeGuardImplBase
  44 class AutoTestingHookBase {
  45  public:
  46   virtual ~AutoTestingHookBase() {}
  47 };
  48
  49 // This is the typedef you normally use for the class, e.g.
  50 //
  51 // AutoTestingHook hook = MakeTestingHook(TargetFunc, HookTargetFunc);
  52 //
  53 // The 'hook' variable will then be destroyed when it goes out of scope.
  54 //
  55 // NOTE: You must not hold this type as a member of another class.  Its
  56 // destructor will not get called.
  57 typedef const AutoTestingHookBase& AutoTestingHook;
  58
  59 // This is the class you must use when holding a hook as a member of another
  60 // class, e.g.
  61 //
  62 // public:
  63 //  AutoTestingHookHolder holder_;
  64 //  MyClass() : my_hook_holder(MakeTestingHookHolder(Target, Hook)) {}
  65 class AutoTestingHookHolder {
  66  public:
  67   explicit AutoTestingHookHolder(AutoTestingHookBase* hook) : hook_(hook) {}
  68   ~AutoTestingHookHolder() { delete hook_; }
  69  private:
  70   AutoTestingHookHolder() {}  // disallow
  71   AutoTestingHookBase* hook_;
  72 };
  73
  74 // This class helps patch a function, then unpatch it when the object exits
  75 // scope, and also maintains the pointer to the original function stub.
  76 //
  77 // To enable use of the class without having to explicitly provide the
  78 // type of the function pointers (and instead only providing it
  79 // implicitly) we use the same trick as ScopeGuard (see
  80 // common/scope_cleanup.h) uses, so to create a hook you use the MakeHook
  81 // function rather than a constructor.
  82 //
  83 // NOTE:  This function is only safe for e.g. unit tests and _not_ for
  84 // production code.  See PreamblePatcher class for details.
  85 template <typename T>
  86 class AutoTestingHookImpl : public AutoTestingHookBase {
  87  public:
  88   static AutoTestingHookImpl<T> MakeTestingHook(T target_function,
  89                                                 T replacement_function,
  90                                                 bool do_it) {
  91     return AutoTestingHookImpl<T>(target_function, replacement_function, do_it);
  92   }
  93
  94   static AutoTestingHookImpl<T>* MakeTestingHookHolder(T target_function,
  95                                                        T replacement_function,
  96                                                        bool do_it) {
  97     return new AutoTestingHookImpl<T>(target_function,
  98                                       replacement_function, do_it);
  99   }
 100
 101   ~AutoTestingHookImpl() {
 102     if (did_it_) {
 103       SIDESTEP_CHK(SIDESTEP_SUCCESS == PreamblePatcher::Unpatch(
 104           (void*)target_function_, (void*)replacement_function_,
 105           (void*)original_function_));
 106     }
 107   }
 108
 109   // Returns a pointer to the original function.  To use this method you will
 110   // have to explicitly create an AutoTestingHookImpl of the specific
 111   // function pointer type (i.e. not use the AutoTestingHook typedef).
 112   T original_function() {
 113     return original_function_;
 114   }
 115
 116  private:
 117   AutoTestingHookImpl(T target_function, T replacement_function, bool do_it)
 118       : target_function_(target_function),
 119         original_function_(NULL),
 120         replacement_function_(replacement_function),
 121         did_it_(do_it) {
 122     if (do_it) {
 123       SIDESTEP_CHK(SIDESTEP_SUCCESS == PreamblePatcher::Patch(target_function,
 124                                                      replacement_function,
 125                                                      &original_function_));
 126     }
 127   }
 128
 129   T target_function_;  // always valid
 130   T original_function_;  // always valid
 131   T replacement_function_;  // always valid
 132   bool did_it_;  // Remember if we did it or not...
 133 };
 134
 135 template <typename T>
 136 inline AutoTestingHookImpl<T> MakeTestingHook(T target,
 137                                               T replacement,
 138                                               bool do_it) {
 139   return AutoTestingHookImpl<T>::MakeTestingHook(target, replacement, do_it);
 140 }
 141
 142 template <typename T>
 143 inline AutoTestingHookImpl<T> MakeTestingHook(T target, T replacement) {
 144   return AutoTestingHookImpl<T>::MakeTestingHook(target, replacement, true);
 145 }
 146
 147 template <typename T>
 148 inline AutoTestingHookImpl<T>* MakeTestingHookHolder(T target, T replacement) {
 149   return AutoTestingHookImpl<T>::MakeTestingHookHolder(target, replacement,
 150                                                        true);
 151 }
 152
 153 };  // namespace sidestep
 154
 155 #endif  // CEEE_TESTING_SIDESTEP_AUTO_TESTING_HOOK_H_