dom/base/mozAutoDocUpdate.h

   1 /* This Source Code Form is subject to the terms of the Mozilla Public
   2  * License, v. 2.0. If a copy of the MPL was not distributed with this
   3  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   4
   5 #ifndef mozAutoDocUpdate_h_
   6 #define mozAutoDocUpdate_h_
   7
   8 #include "nsContentUtils.h" // For AddScriptBlocker() and RemoveScriptBlocker().
   9 #include "nsIDocument.h"
  10 #include "nsIDocumentObserver.h"
  11
  12 /**
  13  * Helper class to automatically handle batching of document updates.  This
  14  * class will call BeginUpdate on construction and EndUpdate on destruction on
  15  * the given document with the given update type.  The document could be null,
  16  * in which case no updates will be called.  The constructor also takes a
  17  * boolean that can be set to false to prevent notifications.
  18  */
  19 class MOZ_STACK_CLASS mozAutoDocUpdate
  20 {
  21 public:
  22   mozAutoDocUpdate(nsIDocument* aDocument, nsUpdateType aUpdateType,
  23                    bool aNotify) :
  24     mDocument(aNotify ? aDocument : nullptr),
  25     mUpdateType(aUpdateType)
  26   {
  27     if (mDocument) {
  28       mDocument->BeginUpdate(mUpdateType);
  29     }
  30     else {
  31       nsContentUtils::AddScriptBlocker();
  32     }
  33   }
  34
  35   ~mozAutoDocUpdate()
  36   {
  37     if (mDocument) {
  38       mDocument->EndUpdate(mUpdateType);
  39     }
  40     else {
  41       nsContentUtils::RemoveScriptBlocker();
  42     }
  43   }
  44
  45 private:
  46   nsCOMPtr<nsIDocument> mDocument;
  47   nsUpdateType mUpdateType;
  48 };
  49
  50 #define MOZ_AUTO_DOC_UPDATE_PASTE2(tok,line) tok##line
  51 #define MOZ_AUTO_DOC_UPDATE_PASTE(tok,line) \
  52   MOZ_AUTO_DOC_UPDATE_PASTE2(tok,line)
  53 #define MOZ_AUTO_DOC_UPDATE(doc,type,notify) \
  54   mozAutoDocUpdate MOZ_AUTO_DOC_UPDATE_PASTE(_autoDocUpdater_, __LINE__) \
  55   (doc,type,notify)
  56
  57
  58 /**
  59  * Creates an update batch only under certain conditions.
  60  * Use this rather than mozAutoDocUpdate when you expect inner updates
  61  * to notify but you don't always want to spec cycles creating a batch.
  62  * This is needed to avoid having this batch always create a blocker,
  63  * but then have inner mozAutoDocUpdate call the last EndUpdate before.
  64  * we remove that blocker. See bug 423269.
  65  */
  66 class MOZ_STACK_CLASS mozAutoDocConditionalContentUpdateBatch
  67 {
  68 public:
  69   mozAutoDocConditionalContentUpdateBatch(nsIDocument* aDocument,
  70                                           bool aNotify) :
  71     mDocument(aNotify ? aDocument : nullptr)
  72   {
  73     if (mDocument) {
  74       mDocument->BeginUpdate(UPDATE_CONTENT_MODEL);
  75     }
  76   }
  77
  78   ~mozAutoDocConditionalContentUpdateBatch()
  79   {
  80     if (mDocument) {
  81       mDocument->EndUpdate(UPDATE_CONTENT_MODEL);
  82     }
  83   }
  84
  85 private:
  86   nsCOMPtr<nsIDocument> mDocument;
  87 };
  88
  89 #endif