xpcom/base/LogModulePrefWatcher.cpp

   1 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* vim: set ts=8 sts=2 et sw=2 tw=80: */
   3 /* This Source Code Form is subject to the terms of the Mozilla Public
   4  * License, v. 2.0. If a copy of the MPL was not distributed with this
   5  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   6
   7 #include "LogModulePrefWatcher.h"
   8
   9 #include "mozilla/Logging.h"
  10 #include "mozilla/Preferences.h"
  11 #include "mozilla/Services.h"
  12 #include "nsIObserverService.h"
  13 #include "nsString.h"
  14 #include "nsXULAppAPI.h"
  15 #include "base/process_util.h"
  16
  17 static const char kLoggingPrefPrefix[] = "logging.";
  18 static const char kLoggingConfigPrefPrefix[] = "logging.config";
  19 static const int kLoggingConfigPrefixLen = sizeof(kLoggingConfigPrefPrefix) - 1;
  20 static const char kLoggingPrefClearOnStartup[] =
  21     "logging.config.clear_on_startup";
  22 static const char kLoggingPrefLogFile[] = "logging.config.LOG_FILE";
  23 static const char kLoggingPrefAddTimestamp[] = "logging.config.add_timestamp";
  24 static const char kLoggingPrefSync[] = "logging.config.sync";
  25 static const char kLoggingPrefStacks[] = "logging.config.profilerstacks";
  26
  27 namespace mozilla {
  28
  29 NS_IMPL_ISUPPORTS(LogModulePrefWatcher, nsIObserver)
  30
  31 /**
  32  * Resets all the preferences in the logging. branch
  33  * This is needed because we may crash while logging, and this would cause us
  34  * to log after restarting as well.
  35  *
  36  * If logging after restart is desired, set the logging.config.clear_on_startup
  37  * pref to false, or use the MOZ_LOG_FILE and MOZ_LOG_MODULES env vars.
  38  */
  39 static void ResetExistingPrefs() {
  40   nsTArray<nsCString> names;
  41   nsresult rv =
  42       Preferences::GetRootBranch()->GetChildList(kLoggingPrefPrefix, names);
  43   if (NS_SUCCEEDED(rv)) {
  44     for (auto& name : names) {
  45       // Clearing the pref will cause it to reload, thus resetting the log level
  46       Preferences::ClearUser(name.get());
  47     }
  48   }
  49 }
  50
  51 /**
  52  * Loads the log level from the given pref and updates the corresponding
  53  * LogModule.
  54  */
  55 static void LoadPrefValue(const char* aName) {
  56   LogLevel logLevel = LogLevel::Disabled;
  57
  58   nsresult rv;
  59   int32_t prefLevel = 0;
  60   nsAutoCString prefValue;
  61
  62   if (strncmp(aName, kLoggingConfigPrefPrefix, kLoggingConfigPrefixLen) == 0) {
  63     nsAutoCString prefName(aName);
  64
  65     if (prefName.EqualsLiteral(kLoggingPrefLogFile)) {
  66       rv = Preferences::GetCString(aName, prefValue);
  67       // The pref was reset. Clear the user file.
  68       if (NS_FAILED(rv) || prefValue.IsEmpty()) {
  69         LogModule::SetLogFile(nullptr);
  70         return;
  71       }
  72
  73       // If the pref value doesn't have a PID placeholder, append it to the end.
  74       if (!strstr(prefValue.get(), MOZ_LOG_PID_TOKEN)) {
  75         prefValue.AppendLiteral(MOZ_LOG_PID_TOKEN);
  76       }
  77
  78       LogModule::SetLogFile(prefValue.BeginReading());
  79     } else if (prefName.EqualsLiteral(kLoggingPrefAddTimestamp)) {
  80       bool addTimestamp = Preferences::GetBool(aName, false);
  81       LogModule::SetAddTimestamp(addTimestamp);
  82     } else if (prefName.EqualsLiteral(kLoggingPrefSync)) {
  83       bool sync = Preferences::GetBool(aName, false);
  84       LogModule::SetIsSync(sync);
  85     } else if (prefName.EqualsLiteral(kLoggingPrefStacks)) {
  86       bool captureStacks = Preferences::GetBool(aName, false);
  87       LogModule::SetCaptureStacks(captureStacks);
  88     }
  89     return;
  90   }
  91
  92   if (Preferences::GetInt(aName, &prefLevel) == NS_OK) {
  93     logLevel = ToLogLevel(prefLevel);
  94   } else if (Preferences::GetCString(aName, prefValue) == NS_OK) {
  95     if (prefValue.LowerCaseEqualsLiteral("error")) {
  96       logLevel = LogLevel::Error;
  97     } else if (prefValue.LowerCaseEqualsLiteral("warning")) {
  98       logLevel = LogLevel::Warning;
  99     } else if (prefValue.LowerCaseEqualsLiteral("info")) {
 100       logLevel = LogLevel::Info;
 101     } else if (prefValue.LowerCaseEqualsLiteral("debug")) {
 102       logLevel = LogLevel::Debug;
 103     } else if (prefValue.LowerCaseEqualsLiteral("verbose")) {
 104       logLevel = LogLevel::Verbose;
 105     }
 106   }
 107
 108   const char* moduleName = aName + strlen(kLoggingPrefPrefix);
 109   LogModule::Get(moduleName)->SetLevel(logLevel);
 110 }
 111
 112 static void LoadExistingPrefs() {
 113   nsIPrefBranch* root = Preferences::GetRootBranch();
 114   if (!root) {
 115     return;
 116   }
 117
 118   nsTArray<nsCString> names;
 119   nsresult rv = root->GetChildList(kLoggingPrefPrefix, names);
 120   if (NS_SUCCEEDED(rv)) {
 121     for (auto& name : names) {
 122       LoadPrefValue(name.get());
 123     }
 124   }
 125 }
 126
 127 LogModulePrefWatcher::LogModulePrefWatcher() = default;
 128
 129 void LogModulePrefWatcher::RegisterPrefWatcher() {
 130   RefPtr<LogModulePrefWatcher> prefWatcher = new LogModulePrefWatcher();
 131   Preferences::AddStrongObserver(prefWatcher, kLoggingPrefPrefix);
 132
 133   nsCOMPtr<nsIObserverService> observerService =
 134       mozilla::services::GetObserverService();
 135   if (observerService && XRE_IsParentProcess()) {
 136     observerService->AddObserver(prefWatcher,
 137                                  "browser-delayed-startup-finished", false);
 138   }
 139
 140   LoadExistingPrefs();
 141 }
 142
 143 NS_IMETHODIMP
 144 LogModulePrefWatcher::Observe(nsISupports* aSubject, const char* aTopic,
 145                               const char16_t* aData) {
 146   if (strcmp(NS_PREFBRANCH_PREFCHANGE_TOPIC_ID, aTopic) == 0) {
 147     NS_LossyConvertUTF16toASCII prefName(aData);
 148     LoadPrefValue(prefName.get());
 149   } else if (strcmp("browser-delayed-startup-finished", aTopic) == 0) {
 150     bool clear = Preferences::GetBool(kLoggingPrefClearOnStartup, true);
 151     if (clear) {
 152       ResetExistingPrefs();
 153     }
 154     nsCOMPtr<nsIObserverService> observerService =
 155         mozilla::services::GetObserverService();
 156     if (observerService) {
 157       observerService->RemoveObserver(this, "browser-delayed-startup-finished");
 158     }
 159   }
 160
 161   return NS_OK;
 162 }
 163
 164 }  // namespace mozilla