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.
+const char kMessageHeader[] = "%03d~ %04x %s ~\n";

[scottmg, 2015/02/01 19:55:35]

GetTickCount will normally be larger than 4 digits, either remove the 04, or
make it larger?

[cpu_(ooo_6.6-7.5), 2015/02/03 02:44:58]

Done.

+

[cpu_(ooo_6.6-7.5), 2015/02/01 19:08:41]

my loggers are never free form, that is, you can always write a log reader
without needing AI, thus the table.

[scottmg, 2015/02/01 19:55:35]

until version has a ')' in it!

[cpu_(ooo_6.6-7.5), 2015/02/03 02:44:58]

Acknowledged.

+// 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(), txt.size(), &written, nullptr);
+  return (rc == TRUE);
+}
+
+// Uses |kMessages| at |index| above to write to disk a formated log line.
+// The format is: <index>~ <tick_count> <message> ~\n"
+bool WriteFormatedLogLine(HANDLE file, size_t index, ...) {

[scottmg, 2015/02/01 19:55:35]

Formated -> Formatted, and in comments

[cpu_(ooo_6.6-7.5), 2015/02/03 02:44:58]

Done.

+  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 formated 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, arraysize(time_buf), &local_time);

[scottmg, 2015/02/01 19:55:35]

you can just remove the arraysize arg, as there's a [N] overload in C++.

[cpu_(ooo_6.6-7.5), 2015/02/03 02:44:58]

Done.

+  time_buf[24] = '\0';
+  return time_buf;
+}

[cpu_(ooo_6.6-7.5), 2015/02/01 19:08:41]

the [24] = 0 is because stupid thing puts \n\0 always.

+
+}  // 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

[scottmg, 2015/02/01 19:55:35]

capital Opening

[cpu_(ooo_6.6-7.5), 2015/02/03 02:44:58]

Done.

+  // for anything else.

[cpu_(ooo_6.6-7.5), 2015/02/01 19:08:41]

I am having bruce change our logging to use This One Weird Trick to make Your
Logging Awesome.

[scottmg, 2015/02/01 19:55:35]

Nice, hadn't used that before.

+  auto kShareAll = FILE_SHARE_READ | FILE_SHARE_WRITE | FILE_SHARE_DELETE;

[scottmg, 2015/02/01 19:55:35]

I find all these auto's a little frightening, but I guess in this case if it
compiles it's OK.

+  file_ = ::CreateFile(logfile.value().c_str(),
+                       FILE_APPEND_DATA, kShareAll,
+                       nullptr,
+                       OPEN_ALWAYS, FILE_ATTRIBUTE_NORMAL,
+                       NULL);

[scottmg, 2015/02/01 19:55:35]

NULL->nullptr

+  if (file_ == INVALID_HANDLE_VALUE)
+    return;
+  WriteFormatedLogLine(
+      file_, 0, ::GetCurrentProcessId(), PRODUCT_VERSION, DateTime().c_str());
+}
+
+Logger::~Logger() {
+  if (file_ != INVALID_HANDLE_VALUE) {
+    WriteFormatedLogLine(file_, 1, ::GetCurrentProcessId(), DateTime().c_str());

[scottmg, 2015/02/01 19:55:35]

The 0, 1, etc. seem a bit non-obvious. I don't understand who will be calling
this, but I guess something else needs to go in the header later?

[cpu_(ooo_6.6-7.5), 2015/02/03 02:44:58]

So the idea is that the logger will have methods with GoodNames(tm) so the
numbers only need to be known within this file. We could also have an enum in
this file but seemed more effort.

+    ::CloseHandle(file_);
+  }
+}
+
+}  // namespace caps
+