Refactor MachMultiprocess

util/test/multiprocess.h

 // Copyright 2014 The Crashpad Authors. All rights reserved.
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
 // You may obtain a copy of the License at
 //
 //     http://www.apache.org/licenses/LICENSE-2.0
 //
 // Unless required by applicable law or agreed to in writing, software
 // distributed under the License is distributed on an "AS IS" BASIS,
 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-#ifndef CRASHPAD_UTIL_TEST_MAC_MACH_MULTIPROCESS_H_
-#define CRASHPAD_UTIL_TEST_MAC_MACH_MULTIPROCESS_H_
+#ifndef CRASHPAD_UTIL_TEST_MULTIPROCESS_H_
+#define CRASHPAD_UTIL_TEST_MULTIPROCESS_H_
 
-#include <mach/mach.h>
 #include <unistd.h>
 
 #include "base/basictypes.h"
 
 namespace crashpad {
 namespace test {
 
 namespace internal {
-struct MachMultiprocessInfo;
-}  // namespace internal
+struct MultiprocessInfo;
+};
 
-//! \brief Manages a Mach-aware multiprocess test.
+//! \brief Manages a multiprocess test.
 //!
-//! These tests are `fork()`-based. The parent process has access to the child
-//! process’ task port. The parent and child processes are able to communicate
-//! via Mach IPC, and via a pair of POSIX pipes.
+//! These tests are `fork()`-based. The parent and child processes are able to
+//! communicate via a pair of POSIX pipes.
 //!
 //! Subclasses are expected to implement the parent and child by overriding the
 //! appropriate methods.
-class MachMultiprocess {
+class Multiprocess {
  public:
-  MachMultiprocess();
+  Multiprocess();
 
   //! \brief Runs the test.
   //!
-  //! This method establishes the proper testing environment and calls
-  //! RunParent() in the parent process and RunChild() in the child process.
+  //! This method establishes the proper testing environment by calling
+  //! PreFork(), then calls `fork()`. In the parent process, it calls
+  //! RunParent(), and in the child process, it calls RunChild().
   //!
   //! This method uses gtest assertions to validate the testing environment. If
   //! the testing environment cannot be set up properly, it is possible that
-  //! Parent() or Child() will not be called. In the parent process, this method
-  //! also waits for the child process to exit after Parent() returns, and
-  //! verifies that it exited cleanly with gtest assertions.
+  //! MultiprocessParent() or MultiprocessChild() will not be called. In the
+  //! parent process, this method also waits for the child process to exit after
+  //! MultiprocessParent() returns, and verifies that it exited cleanly without
+  //! raising any gtest assertions.
   void Run();
 
  protected:
-  ~MachMultiprocess();
+  ~Multiprocess();
 
-  //! \brief The subclass-provided parent routine.
+  //! \brief Establishes the proper testing environment prior to forking.
   //!
-  //! Test failures should be reported via gtest: `EXPECT_*()`, `ASSERT_*()`,
-  //! `FAIL()`, etc.
+  //! Subclasses that solely implement a test should not need to override this
+  //! method. Subclasses that do not implement tests but instead implement
+  //! additional testing features on top of this class may override this method
+  //! provided that they call the superclass’ implementation first as follows:
   //!
-  //! This method must not use a `wait()`-family system call to wait for the
-  //! child process to exit, as this is handled by RunParent().
+  //! \code
+  //!   virtual void PreFork() override {
+  //!     Multiprocess::PreFork();
+  //!     if (testing::Test::HasFatalAssertions()) {
+  //!       return;
+  //!     }
   //!
-  //! Subclasses must implement this method to define how the parent operates.
-  virtual void Parent() = 0;
-
-  //! \brief The subclass-provided child routine.
+  //!     // Place subclass-specific pre-fork code here.
+  //!   }
+  //! \endcode
   //!
-  //! Test failures should be reported via gtest: `EXPECT_*()`, `ASSERT_*()`,
-  //! `FAIL()`, etc.
-  //!
-  //! Subclasses must implement this method to define how the child operates.
-  virtual void Child() = 0;
+  //! Subclass implementations may signal failure by raising their own fatal
+  //! gtest assertions.
+  virtual void PreFork();
 
   //! \brief Returns the child process’ process ID.
   //!
   //! This method may only be called by the parent process.
   pid_t ChildPID() const;
 
   //! \brief Returns the read pipe’s file descriptor.
   //!
   //! This method may be called by either the parent or the child process.
   //! Anything written to the write pipe in the partner process will appear
   //! on the this file descriptor in this process.
   int ReadPipeFD() const;
 
   //! \brief Returns the write pipe’s file descriptor.
   //!
   //! This method may be called by either the parent or the child process.
   //! Anything written to this file descriptor in this process will appear on
   //! the read pipe in the partner process.
   int WritePipeFD() const;
 
-  //! \brief Returns a receive right for the local port.
-  //!
-  //! This method may be called by either the parent or the child process. It
-  //! returns a receive right, with a corresponding send right held in the
-  //! opposing process.
-  mach_port_t LocalPort() const;
-
-  //! \brief Returns a send right for the remote port.
-  //!
-  //! This method may be called by either the parent or the child process. It
-  //! returns a send right, with the corresponding receive right held in the
-  //! opposing process.
-  mach_port_t RemotePort() const;
-
-  //! \brief Returns a send right for the child’s task port.
-  //!
-  //! This method may only be called by the parent process.
-  mach_port_t ChildTask() const;
-
  private:
   //! \brief Runs the parent side of the test.
   //!
-  //! This method establishes the parent’s environment, performs the handshake
-  //! with the child, calls Parent(), and waits for the child process to exit.
-  //! Assuming that the environment can be set up correctly and the child exits
-  //! successfully, the test will pass.
+  //! This method establishes the parent’s environment and calls
+  //! MultiprocessParent().
   void RunParent();
 
   //! \brief Runs the child side of the test.
   //!
-  //! This method establishes the child’s environment, performs the handshake
-  //! with the parent, calls Child(), and exits cleanly. However, if any failure
-  //! (via fatal or nonfatal gtest assertion) is detected, the child will exit
-  //! with a failure status.
+  //! This method establishes the child’s environment, calls
+  //! MultiprocessChild(), and exits cleanly. However, if any failure (via fatal
+  //! or nonfatal gtest assertion) is detected, the child will exit with a
+  //! failure status.
   void RunChild();
 
-  internal::MachMultiprocessInfo* info_;
+  //! \brief The subclass-provided parent routine.
+  //!
+  //! Test failures should be reported via gtest: `EXPECT_*()`, `ASSERT_*()`,
+  //! `FAIL()`, etc.
+  //!
+  //! This method must not use a `wait()`-family system call to wait for the
+  //! child process to exit, as this is handled by this class.
+  //!
+  //! Subclasses must implement this method to define how the parent operates.
+  virtual void MultiprocessParent() = 0;
 
-  DISALLOW_COPY_AND_ASSIGN(MachMultiprocess);
+  //! \brief The subclass-provided child routine.
+  //!
+  //! Test failures should be reported via gtest: `EXPECT_*()`, `ASSERT_*()`,
+  //! `FAIL()`, etc.
+  //!
+  //! Subclasses must implement this method to define how the child operates.
+  virtual void MultiprocessChild() = 0;
+
+  internal::MultiprocessInfo* info_;
+
+  DISALLOW_COPY_AND_ASSIGN(Multiprocess);
 };
 
 }  // namespace test
 }  // namespace crashpad
 
-#endif  // CRASHPAD_UTIL_TEST_MAC_MACH_MULTIPROCESS_H_
+#endif  // CRASHPAD_UTIL_TEST_MULTIPROCESS_H_