Refactor multiprocess test code to allow multiple child processes to be launched.

test/win/win_multiprocess.cc

Index: test/win/win_multiprocess.cc
diff --git a/test/win/win_multiprocess.cc b/test/win/win_multiprocess.cc
index 44b0e22ed058e5a36b6e99173e48d920a5ec5028..ed25fa751b2112ed60df8e5de6adbd54a9c3b9e6 100644
--- a/test/win/win_multiprocess.cc
+++ b/test/win/win_multiprocess.cc
@@ -20,7 +20,6 @@
 #include "base/scoped_generic.h"
 #include "base/strings/stringprintf.h"
 #include "base/strings/utf_string_conversions.h"
-#include "gtest/gtest.h"
 #include "util/stdlib/string_number_conversion.h"
 #include "util/string/split_string.h"
 #include "test/paths.h"
@@ -28,175 +27,48 @@
 namespace crashpad {
 namespace test {
 
-namespace {
-
-const char kIsMultiprocessChild[] = "--is-multiprocess-child";
-
-struct LocalFreeTraits {
-  static HLOCAL InvalidValue() { return nullptr; }
-  static void Free(HLOCAL mem) {
-    if (LocalFree(mem) != nullptr)
-      PLOG(ERROR) << "LocalFree";
-  }
-};
-
-using ScopedLocalFree = base::ScopedGeneric<HLOCAL, LocalFreeTraits>;
-
-bool GetSwitch(const char* switch_name, std::string* value) {
-  int num_args;
-  wchar_t** args = CommandLineToArgvW(GetCommandLine(), &num_args);
-  ScopedLocalFree scoped_args(args);  // Take ownership.
-  if (!args) {
-    PLOG(ERROR) << "couldn't parse command line";
-    return false;
-  }
-
-  std::string switch_name_with_equals(switch_name);
-  switch_name_with_equals += "=";
-  for (size_t i = 1; i < num_args; ++i) {
-    const wchar_t* arg = args[i];
-    std::string arg_as_utf8 = base::UTF16ToUTF8(arg);
-    if (arg_as_utf8.compare(
-            0, switch_name_with_equals.size(), switch_name_with_equals) == 0) {
-      *value = arg_as_utf8.substr(switch_name_with_equals.size());
-      return true;
-    }
-  }
-
-  return false;
-}
-
-}  // namespace
-
-WinMultiprocess::WinMultiprocess() {
-}
-
-void WinMultiprocess::Run() {
-  std::string switch_value;
-  if (GetSwitch(kIsMultiprocessChild, &switch_value)) {
-    // If we're in the child, then set up the handles we inherited from the
-    // parent. These are inherited from the parent and so are open and have the
-    // same value as in the parent. The values are passed to the child on the
-    // command line.
-    std::string left, right;
-    ASSERT_TRUE(SplitString(switch_value, '|', &left, &right));
-    unsigned int c2p_write, p2c_read;
-    ASSERT_TRUE(StringToNumber(left, &c2p_write));
-    ASSERT_TRUE(StringToNumber(right, &p2c_read));
-    pipe_c2p_write_.reset(reinterpret_cast<HANDLE>(c2p_write));
-    pipe_p2c_read_.reset(reinterpret_cast<HANDLE>(p2c_read));
-
-    // Notify the parent that it's OK to proceed. We only need to wait to get to
-    // the process entry point, but this is the easiest place we can notify.
-    char c = ' ';
-    CheckedWriteFile(WritePipeHandle(), &c, sizeof(c));
-
-    // Invoke the child side of the test.
-    WinMultiprocessChild();
-    exit(0);
-  } else {
-    // If we're in the parent, make pipes for child-to-parent and
-    // parent-to-child communication. Mark them as inheritable via the
-    // SECURITY_ATTRIBUTES, but use SetHandleInformation to ensure that the
-    // parent sides are not inherited.
-    SECURITY_ATTRIBUTES security_attributes = {0};
-    security_attributes.nLength = sizeof(SECURITY_ATTRIBUTES);
-    security_attributes.bInheritHandle = true;
-
-    HANDLE c2p_read, c2p_write;
-    PCHECK(CreatePipe(&c2p_read, &c2p_write, &security_attributes, 0));
-    PCHECK(SetHandleInformation(c2p_read, HANDLE_FLAG_INHERIT, 0));
-    pipe_c2p_read_.reset(c2p_read);
-    pipe_c2p_write_.reset(c2p_write);
-
-    HANDLE p2c_read, p2c_write;
-    PCHECK(CreatePipe(&p2c_read, &p2c_write, &security_attributes, 0));
-    PCHECK(SetHandleInformation(p2c_write, HANDLE_FLAG_INHERIT, 0));
-    pipe_p2c_read_.reset(p2c_read);
-    pipe_p2c_write_.reset(p2c_write);
-
-    // Build a command line for the child process that tells it only to run the
-    // current test, and to pass down the values of the pipe handles.
-    const ::testing::TestInfo* const test_info =
-        ::testing::UnitTest::GetInstance()->current_test_info();
-    std::wstring command_line = Paths::Executable().value() + L" " +
-                                base::UTF8ToUTF16(base::StringPrintf(
-                                    "--gtest_filter=%s.%s %s=0x%x|0x%x",
-                                    test_info->test_case_name(),
-                                    test_info->name(),
-                                    kIsMultiprocessChild,
-                                    c2p_write,
-                                    p2c_read));
-    STARTUPINFO startup_info = {0};
-    startup_info.cb = sizeof(startup_info);
-    startup_info.hStdInput = GetStdHandle(STD_INPUT_HANDLE);
-    startup_info.hStdOutput = GetStdHandle(STD_OUTPUT_HANDLE);
-    startup_info.hStdError = GetStdHandle(STD_ERROR_HANDLE);
-    startup_info.dwFlags = STARTF_USESTDHANDLES;
-    PROCESS_INFORMATION process_info;
-    PCHECK(
-        CreateProcess(Paths::Executable().value().c_str(),
-                      &command_line[0],  // This cannot be constant, per MSDN.
-                      nullptr,
-                      nullptr,
-                      true,  // Inherit handles.
-                      0,
-                      nullptr,
-                      nullptr,
-                      &startup_info,
-                      &process_info));
-    child_handle_.reset(process_info.hProcess);
-    CloseHandle(process_info.hThread);
-
-    // Block until the child process has launched. CreateProcess() returns
-    // immediately, and test code expects process initialization to have
-    // completed so it can, for example, use the process handle.
-    char c;
-    CheckedReadFile(pipe_c2p_read_.get(), &c, sizeof(c));
-    ASSERT_EQ(' ', c);
-
-    // These have been passed to the child, close our side.
-    pipe_c2p_write_.reset();
-    pipe_p2c_read_.reset();
-
-    WinMultiprocessParent();
-  }
+WinMultiprocess::WinMultiprocess()
+    : child_handles_(nullptr), child_process_helper_(nullptr) {
 }
 
 WinMultiprocess::~WinMultiprocess() {
 }
 
 FileHandle WinMultiprocess::ReadPipeHandle() const {
-  FileHandle handle =
-      child_handle_.get() ? pipe_c2p_read_.get() : pipe_p2c_read_.get();
-  CHECK(handle != nullptr);
-  return handle;
+  if (child_handles_)
+    return child_handles_->read.get();
+  CHECK(child_process_helper_);
+  return child_process_helper_->ReadPipeHandleForwarder();
 }
 
 FileHandle WinMultiprocess::WritePipeHandle() const {
-  FileHandle handle =
-      child_handle_.get() ? pipe_p2c_write_.get() : pipe_c2p_write_.get();
-  CHECK(handle != nullptr);
-  return handle;
+  if (child_handles_)
+    return child_handles_->write.get();
+  CHECK(child_process_helper_);
+  return child_process_helper_->WritePipeHandleForwarder();
 }
 
 void WinMultiprocess::CloseReadPipe() {
-  if (child_handle_.get())
-    pipe_c2p_read_.reset();
-  else
-    pipe_p2c_read_.reset();
+  if (child_handles_) {
+    child_handles_->read.reset();
+  } else {
+    CHECK(child_process_helper_);
+    child_process_helper_->CloseReadPipeForwarder();
+  }
 }
 
 void WinMultiprocess::CloseWritePipe() {
-  if (child_handle_.get())
-    pipe_p2c_write_.reset();
-  else
-    pipe_c2p_write_.reset();
+  if (child_handles_) {
+    child_handles_->write.reset();
+  } else {
+    CHECK(child_process_helper_);
+    child_process_helper_->CloseWritePipeForwarder();
+  }
 }
 
 HANDLE WinMultiprocess::ChildProcess() const {
-  EXPECT_NE(nullptr, child_handle_.get());
-  return child_handle_.get();
+  CHECK(child_handles_);
+  return child_handles_->process.get();
 }
 
 }  // namespace test