[Nvda-dev] Branch nvda/displayModel: Rev 3472: NVDAHelper display model: Fix possible assertions/crashes when displayModels were being accessed more than once at the same time.

[NV A. b. c. <nor...@nv...>]

At http://bzr.nvaccess.org/nvda/displayModel

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revno: 3472
revision-id: mi...@ku...-20100430074201-yeovoa098vwxndpq
parent: mi...@ku...-20100430051140-wfod5arysfbazmq1
committer: Michael Curran <mi...@ku...>
branch nick: displayModel
timestamp: Fri 2010-04-30 17:42:01 +1000
message:
  NVDAHelper display model: Fix possible assertions/crashes when displayModels were being accessed more than once at the same time.
  Specific changes:
  *displayModel_t now inherits from LockableAutoFreeObject.
      *The maps that hold displayModels (by window and by memory DC) are instances of a class that contains LockableObject as one of its base classes.
  *Rather than the displayModelMaps criticalSection, acquire and release on each map is used, around any accesses to the individual map.
  *acquireDisplayModel (which fetches or creates a displayModel from a HDC) now calls acquire on the DisplayModel before releasing the map, and returning the displayModel.
  *The RPC function displayModel_getWindowTextInRect appropriately uses acquire and release on the displayModelsByWindow map and on the individual displayModels.
  *Functions that remove displayModels from maps (such as the destroyWindow hook, deleteDC hook and gdi_inprocess_terminate) appropriately call acquire and release on the displayModel maps, and call requestDelete on each displayModel.
  
  This change will probably stop many various assertions/crashes, though one place that it definitly does is holding down up or down arrow in a document in textPad, where we used to see an assertion in the CRT due to corrupt map iterators.