Scrub the vestigal breakpad crash dump attempts metrics code.

components/browser_watcher/crash_reporting_metrics_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 "components/browser_watcher/crash_reporting_metrics_win.h"
-
-#include <stddef.h>
-
-#include <algorithm>
-#include "base/atomicops.h"
-#include "base/guid.h"
-#include "base/logging.h"
-#include "base/macros.h"
-#include "base/strings/safe_sprintf.h"
-#include "base/strings/string_util.h"
-#include "base/strings/utf_string_conversions.h"
-#include "base/win/registry.h"
-
-namespace browser_watcher {
-
-namespace {
-
-// The prior implementation used 0 and 1. Its data collection is inconsistent
-// with ours and it's best to just ignore its records. So we start at 2.
-const DWORD kCrashDumpAttempt = 2;
-const DWORD kDumpWithoutCrashAttempt = 3;
-const DWORD kCrashDumpSuccess = 4;
-const DWORD kCrashDumpFailure = 5;
-const DWORD kDumpWithoutCrashSuccess = 6;
-const DWORD kDumpWithoutCrashFailure = 7;
-
-// A prefix intended to avoid registry value name collisions with other
-// processes (or modules within a single process). It is not necessary for the
-// reading and writing instances to share the prefix value. This array is sized
-// to hold a null-terminated string as generated by base::GenerateGUID.
-char g_unique_prefix[36 + 1] = {0};
-
-// An atomic counter intended  to make each registry value name unique within
-// this process and module.
-base::subtle::Atomic32 g_record_count = 0;
-
-// The length of a null-terminated string consisting of "{GUID}-{COUNT}".
-const size_t kValueNameSize = 36 + 1 + 8 + 1;
-
-void WriteValue(const base::string16& key_path, DWORD value) {
-  // Generate the final value name we'll use (appends the crash number to the
-  // base value name).
-  char value_name_ascii[kValueNameSize] = "";
-  base::char16 value_name_utf16[kValueNameSize] = L"";
-
-  if (base::strings::SafeSPrintf(
-          value_name_ascii, "%s-%x", g_unique_prefix,
-          base::subtle::NoBarrier_AtomicIncrement(&g_record_count, 1)) <= 0) {
-    NOTREACHED();
-  } else {
-    // Since it's an ASCII string, the UTF-16 form is identical with leading 0
-    // bytes. We're avoiding unnecessary heap operations since we're running in
-    // a compromised process.
-    std::copy(value_name_ascii, value_name_ascii + kValueNameSize,
-              value_name_utf16);
-
-    base::win::RegKey reg_key;
-    if (reg_key.Create(HKEY_CURRENT_USER, key_path.c_str(), KEY_SET_VALUE) !=
-        ERROR_SUCCESS) {
-      NOTREACHED();
-    } else {
-      reg_key.WriteValue(value_name_utf16, value);
-    }
-  }
-
-}
-
-}  // namespace
-
-CrashReportingMetrics::CrashReportingMetrics(
-    const base::string16& registry_path)
-    : registry_path_(registry_path) {
-  if (g_unique_prefix[0] == 0) {
-    std::string guid = base::GenerateGUID();
-    // It seems reasonable to assume that the worst possible outcome of two
-    // separate threads trying to do the following would be to store a GUID
-    // value that is a hybrid of the two intended values. Hence we can avoid any
-    // thread-safety caveats in our public API.
-    size_t copied_size = base::strlcpy(g_unique_prefix, guid.c_str(),
-                                       arraysize(g_unique_prefix));
-    DCHECK_EQ(copied_size, guid.length());
-  }
-}
-
-void CrashReportingMetrics::RecordCrashDumpAttempt() {
-  WriteValue(registry_path_, kCrashDumpAttempt);
-}
-
-void CrashReportingMetrics::RecordDumpWithoutCrashAttempt() {
-  WriteValue(registry_path_, kDumpWithoutCrashAttempt);
-}
-void CrashReportingMetrics::RecordCrashDumpAttemptResult(bool succeeded) {
-  WriteValue(registry_path_, succeeded ? kCrashDumpSuccess : kCrashDumpFailure);
-}
-void CrashReportingMetrics::RecordDumpWithoutCrashAttemptResult(
-    bool succeeded) {
-  WriteValue(registry_path_,
-             succeeded ? kDumpWithoutCrashSuccess : kDumpWithoutCrashFailure);
-}
-
-CrashReportingMetrics::Values CrashReportingMetrics::RetrieveAndResetMetrics() {
-  Values values = {0};
-
-  // Open the registry key for iteration.
-  base::win::RegKey regkey;
-  if (regkey.Open(HKEY_CURRENT_USER, registry_path_.c_str(),
-                  KEY_QUERY_VALUE | KEY_SET_VALUE) != ERROR_SUCCESS) {
-    return values;
-  }
-
-  // Track a list of values to delete. We don't modify the registry key while
-  // we're iterating over its values.
-  typedef std::vector<base::string16> StringVector;
-  StringVector to_delete;
-
-  // Iterate over the values in the key counting dumps with and without crashes.
-  // We directly walk the values instead of using RegistryValueIterator in order
-  // to read all of the values as DWORDS instead of strings.
-  base::string16 name;
-  DWORD value = 0;
-  for (int i = regkey.GetValueCount() - 1; i >= 0; --i) {
-    if (regkey.GetValueNameAt(i, &name) == ERROR_SUCCESS &&
-        regkey.ReadValueDW(name.c_str(), &value) == ERROR_SUCCESS) {
-      to_delete.push_back(name);
-      switch (value) {
-        case kCrashDumpAttempt:
-          ++values.crash_dump_attempts;
-          break;
-        case kCrashDumpSuccess:
-          ++values.successful_crash_dumps;
-          break;
-        case kCrashDumpFailure:
-          ++values.failed_crash_dumps;
-          break;
-        case kDumpWithoutCrashAttempt:
-          ++values.dump_without_crash_attempts;
-          break;
-        case kDumpWithoutCrashSuccess:
-          ++values.successful_dumps_without_crash;
-          break;
-        case kDumpWithoutCrashFailure:
-          ++values.failed_dumps_without_crash;
-          break;
-        default:
-          // Presumably a pre-existing record from the previous implementation.
-          // We will delete it.
-          break;
-      }
-    }
-  }
-
-  // Delete the registry keys we've just counted.
-  for (const auto& value_name : to_delete)
-    regkey.DeleteValue(value_name.c_str());
-
-  return values;
-}
-
-}  // namespace browser_watcher