Uploaded image for project: 'Apache Cordova'
  1. Apache Cordova
  2. CB-11355

initPlugins() abuse borking plugins on (ajax) loads, and potential fix

    XMLWordPrintableJSON

    Details

      Description

      I'm working on an (ubuntu) plugin that is thread-safe but was causing segfaults everytime I'd (asynch) load a new page or component.

      Trying to run it under gdb, I found that as long as I avoided moving around there were no issues, but every load of a new page or (html) popup would spawn a new thread and somehow re-init my plugin (which is stateful and needs to stay alive).

      The traces looked like so:
      ======================== snip ========================
      [New Thread 0x7fffcf8a9700 (LWP 26618)]
      Debug: Enable plugin "com.example.MyPlugin"
      Debug: Enable plugin "File"
      Debug: Enable plugin "Notification"
      Debug: Enable plugin "com.cordova.Device"
      Debug: Testing "/path/to/project/platforms/ubuntu/native/prefix/www/logo.png"
      [Thread 0x7fffcf8a9700 (LWP 26618) exited]
      Debug: Testing "/path/to/project/platforms/ubuntu/native/prefix/www/cordova.js"
      Debug: Testing "/path/to/project/platforms/ubuntu/native/prefix/www/cordova_plugins.js"
      Debug: Testing "/path/to/project/platforms/ubuntu/native/prefix/www/pageA.html"
      Debug: Testing "/path/to/project/platforms/ubuntu/native/prefix/www/pageB.html"
      Debug: Testing "/path/to/project/platforms/ubuntu/native/prefix/www/index.html"
      Debug: Testing "/path/to/project/platforms/ubuntu/native/prefix/www/libcoreplugins.so"
      [New Thread 0x7fffcf8a9700 (LWP 26619)]
      [Thread 0x7fffcf8a9700 (LWP 26619) exited]
      Debug: Enable plugin "com.example.MyPlugin"
      Debug: Enable plugin "File"
      Debug: Enable plugin "Notification"
      Debug: Enable plugin "com.cordova.Device"
      Debug: Testing "/path/to/project/platforms/ubuntu/native/prefix/www/logo.png"
      Debug: Testing "/path/to/project/platforms/ubuntu/native/prefix/www/cordova.js"
      Debug: Testing "/path/to/project/platforms/ubuntu/native/prefix/www/cordova_plugins.js"
      Debug: Testing "/path/to/project/platforms/ubuntu/native/prefix/www/pageA.html"
      Debug: Testing "/path/to/project/platforms/ubuntu/native/prefix/www/pageB.html"
      Debug: Testing "/path/to/project/platforms/ubuntu/native/prefix/www/index.html"
      Debug: Testing "/path/to/project/platforms/ubuntu/native/prefix/www/libcoreplugins.so"
      [New Thread 0x7fffcf8a9700 (LWP 26621)]
      Debug: Enable plugin "com.example.MyPlugin"
      Debug: Enable plugin "File"
      Debug: Enable plugin "Notification"
      Debug: Enable plugin "com.cordova.Device"
      Debug: Testing "/path/to/project/platforms/ubuntu/native/prefix/www/logo.png"
      [Thread 0x7fffcf8a9700 (LWP 26621) exited]
      Program received signal SIGSEGV, Segmentation fault.
      ======================== /snip ========================

      I tracked down the reason for all the (redundant?) "Enable plugin" events to initPlugins() calls in loadFinished() (in the Ubuntu package/src/cordova.cpp):

      void Cordova::loadFinished(bool ok) {
      Q_UNUSED(ok)
      initPlugins();
      }

      I'm not certain what the purpose of this call is, as the init already happens in Cordova::appLoaded().

      In any case, I've disabled the call and loadFinished() and my plugin is both persistent and has stopped causing segfaults.

      Is there a reason to keep this initPlugins() call in loadFinished()? If so, could we add some kind of

      virtual bool loadOnlyOnce()

      { return false;}

      to the CPlugin base class so we can check for and skip plugins that override it? Or is there some other technique I'm not aware of?

      Thanks,
      Pat Deegan

        Attachments

          Activity

            People

            • Assignee:
              dbarth David Barth
              Reporter:
              psychogenic Pat Deegan
            • Votes:
              0 Vote for this issue
              Watchers:
              3 Start watching this issue

              Dates

              • Created:
                Updated:
                Resolved: