Reimplementation of FunctionStub, to avoid rewriting potentially executing co...

chrome_frame/test/function_stub_unittest.cc

-// Copyright (c) 2009 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 "chrome_frame/function_stub.h"
-#include "testing/gtest/include/gtest/gtest.h"
-
-#define NO_INLINE __declspec(noinline)
-
-namespace {
-
-typedef int (__stdcall* FooPrototype)();
-
-NO_INLINE int __stdcall Foo() {
-  return 1;
-}
-
-NO_INLINE int __stdcall PatchedFoo(FooPrototype original) {
-  return original() + 1;
-}
-
-}  // end namespace
-
-TEST(PatchTests, FunctionStub) {
-  EXPECT_EQ(Foo(), 1);
-  // Create a function stub that calls PatchedFoo and supplies it with
-  // a pointer to Foo.
-  FunctionStub* stub = FunctionStub::Create(reinterpret_cast<uintptr_t>(&Foo),
-                                            &PatchedFoo);
-  EXPECT_TRUE(stub != NULL);
-  // Call the stub as it were Foo().  The call should get forwarded to Foo().
-  FooPrototype patch = reinterpret_cast<FooPrototype>(stub->code());
-  EXPECT_EQ(patch(), 2);
-  // Now neutralize the stub so that it calls Foo() directly without touching
-  // PatchedFoo().
-  // stub->BypassStub(&Foo);
-  stub->BypassStub(reinterpret_cast<void*>(stub->argument()));
-  EXPECT_EQ(patch(), 1);
-  // We're done with the stub.
-  FunctionStub::Destroy(stub);
-}
-
-// Basic tests to check the validity of a stub.
-TEST(PatchTests, FunctionStubCompare) {
-  EXPECT_EQ(Foo(), 1);
-
-  // Detect the absence of a stub
-  FunctionStub* stub = reinterpret_cast<FunctionStub*>(&Foo);
-  EXPECT_FALSE(stub->is_valid());
-
-  stub = FunctionStub::Create(reinterpret_cast<uintptr_t>(&Foo), &PatchedFoo);
-  EXPECT_TRUE(stub != NULL);
-  EXPECT_TRUE(stub->is_valid());
-
-  FooPrototype patch = reinterpret_cast<FooPrototype>(stub->code());
-  EXPECT_EQ(patch(), 2);
-
-  // See if we can get the correct absolute pointer to the hook function
-  // back from the stub.
-  EXPECT_EQ(stub->absolute_target(), reinterpret_cast<uintptr_t>(&PatchedFoo));
-
-  // Also verify that the argument being passed to the hook function is indeed
-  // the pointer to the original function (again, absolute not relative).
-  EXPECT_EQ(stub->argument(), reinterpret_cast<uintptr_t>(&Foo));
-}