bug 1299583 - Don't create backup of files when staging an update. r=mhowell

toolkit/mozapps/update/updater/updater.cpp

@@ -1208,12 +1208,20 @@ RemoveFile::Execute()
     return OK;
   }
 
+  if (sStagedUpdate) {
+    // Staged updates don't need backup files so just remove it.
+    rv = ensure_remove(mFile.get());
+    if (rv) {
+      return rv;
+    }
+  } else {
     // Rename the old file. It will be removed in Finish.
     rv = backup_create(mFile.get());
     if (rv) {
       LOG(("backup_create failed: %d", rv));
       return rv;
     }
+  }
 
   return OK;
 }
@@ -1221,12 +1229,16 @@ RemoveFile::Execute()
 void
 RemoveFile::Finish(int status)
 {
-  if (mSkip)
+  if (mSkip) {
     return;
+  }
 
   LOG(("FINISH REMOVEFILE " LOG_S, mRelPath.get()));
 
+  // Staged updates don't create backup files.
+  if (!sStagedUpdate) {
     backup_finish(mFile.get(), mRelPath.get(), status);
+  }
 }
 
 class RemoveDir : public Action
@@ -1401,9 +1413,15 @@ AddFile::Execute()
   // First make sure that we can actually get rid of any existing file.
   rv = NS_taccess(mFile.get(), F_OK);
   if (rv == 0) {
+    if (sStagedUpdate) {
+      // Staged updates don't need backup files so just remove it.
+      rv = ensure_remove(mFile.get());
+    } else {
       rv = backup_create(mFile.get());
-    if (rv)
+    }
+    if (rv) {
       return rv;
+    }
   } else {
     rv = ensure_parent_dir(mFile.get());
     if (rv)
@@ -1432,11 +1450,15 @@ void
 AddFile::Finish(int status)
 {
   LOG(("FINISH ADD " LOG_S, mRelPath.get()));
+  // Staged updates don't create backup files.
+  if (!sStagedUpdate) {
     // When there is an update failure and a file has been added it is removed
     // here since there might not be a backup to replace it.
-  if (status && mAdded)
+    if (status && mAdded) {
       NS_tremove(mFile.get());
+    }
     backup_finish(mFile.get(), mRelPath.get(), status);
+  }
 }
 
 class PatchFile : public Action
@@ -1662,10 +1684,13 @@ PatchFile::Execute()
     return READ_ERROR;
   }
 
+  // Staged updates don't need backup files.
+  if (!sStagedUpdate) {
     rv = backup_create(mFile.get());
     if (rv) {
       return rv;
     }
+  }
 
 #if defined(HAVE_POSIX_FALLOCATE)
   AutoFile ofile(ensure_open(mFile.get(), NS_T("wb+"), ss.st_mode));
@@ -1753,7 +1778,10 @@ PatchFile::Finish(int status)
 {
   LOG(("FINISH PATCH " LOG_S, mFileRelPath.get()));
 
+  // Staged updates don't create backup files.
+  if (!sStagedUpdate) {
     backup_finish(mFile.get(), mFileRelPath.get(), status);
+  }
 }
 
 class AddIfFile : public AddFile