Bug 911146 - Add nsIAppStartup attribute to tell whether the app was restarted; r=bsmedberg

toolkit/components/startup/nsAppStartup.cpp

@@ -363,6 +363,9 @@ nsAppStartup::Quit(uint32_t aMode)
     }
 
     if (mRestart) {
+      // Mark the next startup as a restart.
+      PR_SetEnv("MOZ_APP_RESTART=1");
+
       /* Firefox-restarts reuse the process so regular process start-time isn't
          a useful indicator of startup time anymore. */
       TimeStamp::RecordProcessRestart();
@@ -522,6 +525,19 @@ nsAppStartup::GetRestarting(bool *aResult)
   return NS_OK;
 }
 
+NS_IMETHODIMP
+nsAppStartup::GetWasRestarted(bool *aResult)
+{
+  char *mozAppRestart = PR_GetEnv("MOZ_APP_RESTART");
+
+  /* When calling PR_SetEnv() with an empty value the existing variable may
+   * be unset or set to the empty string depending on the underlying platform
+   * thus we have to check if the variable is present and not empty. */
+  *aResult = mozAppRestart && (strcmp(mozAppRestart, "") != 0);
+
+  return NS_OK;
+}
+
 NS_IMETHODIMP
 nsAppStartup::SetInterrupted(bool aInterrupted)
 {

toolkit/components/startup/public/nsIAppStartup.idl

@@ -7,7 +7,7 @@
 
 interface nsICmdLineService;
 
-[scriptable, uuid(380618f8-479a-435b-b58e-7398ab937531)]
+[scriptable, uuid(744d6ec0-115f-11e3-9c94-68fd99890b3c)]
 interface nsIAppStartup : nsISupports
 {
     /**
@@ -140,6 +140,12 @@ interface nsIAppStartup : nsISupports
      */
     readonly attribute boolean restarting;
 
+    /**
+     * True if this is the startup following restart, i.e. if the application
+     * was restarted using quit(eRestart*).
+     */
+    readonly attribute boolean wasRestarted;
+
     /** 
      * Returns an object with main, process, firstPaint, sessionRestored properties.
      * Properties may not be available depending on platform or application

xpcom/ds/TimeStamp.cpp

@@ -30,9 +30,8 @@ TimeStamp::ProcessCreation(bool& aIsInconsistent)
      * thus we have to check if the variable is present and not empty. */
     if (mozAppRestart && (strcmp(mozAppRestart, "") != 0)) {
       /* Firefox was restarted, use the first time-stamp we've taken as the new
-       * process startup time and unset MOZ_APP_RESTART. */
+       * process startup time. */
       ts = sFirstTimeStamp;
-      PR_SetEnv("MOZ_APP_RESTART=");
     } else {
       TimeStamp now = Now();
       uint64_t uptime = ComputeProcessUptime();
@@ -57,7 +56,6 @@ TimeStamp::ProcessCreation(bool& aIsInconsistent)
 void
 TimeStamp::RecordProcessRestart()
 {
-  PR_SetEnv("MOZ_APP_RESTART=1");
   sProcessCreation = TimeStamp();
 }