/C++ readability/ - Make Chromoting Host report crashes to Breakpad (Windows only). The user must e…

remoting/host/usage_stats_consent_win.cc

Index: remoting/host/usage_stats_consent_win.cc
diff --git a/remoting/host/usage_stats_consent_win.cc b/remoting/host/usage_stats_consent_win.cc
new file mode 100644
index 0000000000000000000000000000000000000000..3b5b283a0c8caad47043e321c505ad5bc37aa74f
--- /dev/null
+++ b/remoting/host/usage_stats_consent_win.cc
@@ -0,0 +1,57 @@
+// Copyright (c) 2012 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 "remoting/host/usage_stats_consent.h"
+
+#include <windows.h>
+#include <string>
+
+#include "base/stringprintf.h"
+#include "base/win/registry.h"
+#include "remoting/host/constants.h"
+
+namespace {
+
+// The following strings are used to construct the registry key names where
+// we record whether the user has consented to crash dump collection.
+const wchar_t kOmahaClientStateKeyFormat[] =
+    L"Software\\Google\\Update\\%ls\\%ls";
+const wchar_t kOmahaClientState[] = L"ClientState";
+const wchar_t kOmahaClientStateMedium[] = L"ClientStateMedium";
+const wchar_t kOmahaUsagestatsValue[] = L"usagestats";
+
+LONG ReadUsageStatsValue(const wchar_t* state_key, DWORD* usagestats_out) {
+  std::wstring client_state = StringPrintf(kOmahaClientStateKeyFormat,
+                                           state_key,
+                                           remoting::kHostOmahaAppid);
+  base::win::RegKey key;
+  LONG result = key.Open(HKEY_LOCAL_MACHINE, client_state.c_str(), KEY_READ);
+  if (result != ERROR_SUCCESS) {

[Peter Kasting, 2012/06/15 21:19:30]

Nit: You may also shorten as follows:

  return (result == ERROR_SUCCESS) ?
      key.ReadValueDW(kOmahaUsagestatsValue, usagestats_out) : result;

[alexeypa (please no reviews), 2012/06/15 22:13:57]

Ternary operators are less common in code. It seems to be that people tend to
see it as a necessary hack rather than a trivial if statement. So it takes a
little bit more effort to read the code. I don't think it worth a couple of
saved lines.

+    return result;
+  }
+
+  return key.ReadValueDW(kOmahaUsagestatsValue, usagestats_out);
+}
+
+}  // namespace
+
+namespace remoting {
+
+bool IsCrashReportingEnabled() {
+  // The user's consent to collect crash dumps is recored as the "usagestats"
+  // value in the ClientState or ClientStateMedium key. Probe
+  // the ClientStateMedium key first.
+  DWORD value = 0;
+  if (ReadUsageStatsValue(kOmahaClientStateMedium, &value) == ERROR_SUCCESS) {
+    return value != 0;
+  }
+  if (ReadUsageStatsValue(kOmahaClientState, &value) == ERROR_SUCCESS) {
+    return value != 0;
+  }
+
+  // Do not collect anything unless the user has explicitly allowed it.
+  return false;
+}
+
+}  // namespace remoting