Add basic support for CAPS exe

chrome/tools/crash_service/caps/logger_win.cc

+// Copyright 2015 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 <windows.h>
+#include <time.h>
+
+#include "base/files/file_path.h"
+#include "base/strings/stringprintf.h"
+#include "chrome/common/chrome_version_info_values.h"
+#include "chrome/tools/crash_service/caps/logger_win.h"
+
+namespace {
+// Every message has this structure:
+// <index>~ <tick_count> <message> ~\n"
+const char kMessageHeader[] = "%03d~ %08x %s ~\n";
+
+// Do not re-order these messages. Only add at the end.
+const char* kMessages[] {
+  "start pid(%lu) version(%s) time(%s)",                    // 0
+  "exit pid(%lu) time(%s)",                                 // 1
+  "instance found",                                         // 2
+};
+
+bool WriteLogLine(HANDLE file, const std::string& txt) {
+  if (txt.empty())
+    return true;
+  DWORD written;
+  auto rc = ::WriteFile(file, txt.c_str(),
+                        reinterpret_cast<DWORD>(txt.size()),

[scottmg, 2015/02/03 20:43:26]

looks like a real failure, wants static_cast here, not reinterpret_cast (or
base::checked_cast if you're feeling fancy)

+                        &written,
+                        nullptr);
+  return (rc == TRUE);
+}
+
+// Uses |kMessages| at |index| above to write to disk a formatted log line.
+bool WriteFormattedLogLine(HANDLE file, size_t index, ...) {
+  va_list ap;
+  va_start(ap, index);
+  auto fmt = base::StringPrintf(
+      kMessageHeader, index, ::GetTickCount(), kMessages[index]);
+  auto msg = base::StringPrintV(fmt.c_str(), ap);
+  auto rc = WriteLogLine(file, msg.c_str());
+  va_end(ap);
+  return rc;
+}
+
+// Returns the current time and date formatted in standard C style.
+std::string DateTime() {
+  time_t current_time = 0;
+  time(&current_time);
+  struct tm local_time = {0};
+  char time_buf[26] = {0};
+  localtime_s(&local_time, &current_time);
+  asctime_s(time_buf, &local_time);
+  time_buf[24] = '\0';
+  return time_buf;
+}
+
+}  // namespace
+
+namespace caps {
+
+Logger::Logger(const base::FilePath& path) : file_(INVALID_HANDLE_VALUE) {
+  auto logfile = path.Append(L"caps_log.txt");
+  // Opening a file like so allows atomic appends, but can't be used
+  // for anything else.
+  DWORD kShareAll = FILE_SHARE_READ | FILE_SHARE_WRITE | FILE_SHARE_DELETE;
+  file_ = ::CreateFile(logfile.value().c_str(),
+                       FILE_APPEND_DATA, kShareAll,
+                       nullptr,
+                       OPEN_ALWAYS, FILE_ATTRIBUTE_NORMAL,
+                       nullptr);
+  if (file_ == INVALID_HANDLE_VALUE)
+    return;
+  WriteFormattedLogLine(
+      file_, 0, ::GetCurrentProcessId(), PRODUCT_VERSION, DateTime().c_str());
+}
+
+Logger::~Logger() {
+  if (file_ != INVALID_HANDLE_VALUE) {
+    WriteFormattedLogLine(
+        file_, 1, ::GetCurrentProcessId(), DateTime().c_str());
+    ::CloseHandle(file_);
+  }
+}
+
+}  // namespace caps
+