Bug 1158456 - Remove control characters from composition string, and add dom.compositionevent.allow_control_characters pref to control it. r=masayuki

dom/events/TextComposition.cpp

@@ -14,6 +14,7 @@
 #include "mozilla/EventDispatcher.h"
 #include "mozilla/IMEStateManager.h"
 #include "mozilla/MiscEvents.h"
+#include "mozilla/Preferences.h"
 #include "mozilla/TextComposition.h"
 #include "mozilla/TextEvents.h"
 
@@ -43,6 +44,9 @@ TextComposition::TextComposition(nsPresContext* aPresContext,
   , mIsRequestingCancel(false)
   , mRequestedToCommitOrCancel(false)
   , mWasNativeCompositionEndEventDiscarded(false)
+  , mAllowControlCharacters(
+      Preferences::GetBool("dom.compositionevent.allow_control_characters",
+                           false))
 {
 }
 
@@ -133,6 +137,60 @@ TextComposition::OnCompositionEventDiscarded(
   mWasNativeCompositionEndEventDiscarded = true;
 }
 
+static inline bool
+IsControlChar(uint32_t aCharCode)
+{
+  return aCharCode < ' ' || aCharCode == 0x7F;
+}
+
+static size_t
+FindFirstControlCharacter(const nsAString& aStr)
+{
+  const char16_t* sourceBegin = aStr.BeginReading();
+  const char16_t* sourceEnd = aStr.EndReading();
+
+  for (const char16_t* source = sourceBegin; source < sourceEnd; ++source) {
+    if (*source != '\t' && IsControlChar(*source)) {
+      return source - sourceBegin;
+    }
+  }
+
+  return -1;
+}
+
+static void
+RemoveControlCharactersFrom(nsAString& aStr, TextRangeArray* aRanges)
+{
+  size_t firstControlCharOffset = FindFirstControlCharacter(aStr);
+  if (firstControlCharOffset == (size_t)-1) {
+    return;
+  }
+
+  nsAutoString copy(aStr);
+  const char16_t* sourceBegin = copy.BeginReading();
+  const char16_t* sourceEnd = copy.EndReading();
+
+  char16_t* dest = aStr.BeginWriting();
+  if (NS_WARN_IF(!dest)) {
+    return;
+  }
+
+  char16_t* curDest = dest + firstControlCharOffset;
+  size_t i = firstControlCharOffset;
+  for (const char16_t* source = sourceBegin + firstControlCharOffset;
+       source < sourceEnd; ++source) {
+    if (*source == '\t' || !IsControlChar(*source)) {
+      *curDest = *source;
+      ++curDest;
+      ++i;
+    } else if (aRanges) {
+      aRanges->RemoveCharacter(i);
+    }
+  }
+
+  aStr.SetLength(curDest - dest);
+}
+
 void
 TextComposition::DispatchCompositionEvent(
                    WidgetCompositionEvent* aCompositionEvent,
@@ -140,6 +198,10 @@ TextComposition::DispatchCompositionEvent(
                    EventDispatchingCallback* aCallBack,
                    bool aIsSynthesized)
 {
+  if (!mAllowControlCharacters) {
+    RemoveControlCharactersFrom(aCompositionEvent->mData,
+                                aCompositionEvent->mRanges);
+  }
   if (aCompositionEvent->message == NS_COMPOSITION_COMMIT_AS_IS) {
     NS_ASSERTION(!aCompositionEvent->mRanges,
                  "mRanges of NS_COMPOSITION_COMMIT_AS_IS should be null");

dom/events/TextComposition.h

@@ -221,6 +221,13 @@ private:
   // discarded by PresShell due to not safe to dispatch events.
   bool mWasNativeCompositionEndEventDiscarded;
 
+  // Allow control characters appear in composition string.
+  // When this is false, control characters except
+  // CHARACTER TABULATION (horizontal tab) are removed from
+  // both composition string and data attribute of compositionupdate
+  // and compositionend events.
+  bool mAllowControlCharacters;
+
   // Hide the default constructor and copy constructor.
   TextComposition() {}
   TextComposition(const TextComposition& aOther);

modules/libpref/init/all.js

@@ -4713,3 +4713,10 @@ pref("gfx.vsync.refreshdriver", true);
 #ifdef MOZ_SECUREELEMENT
 pref("dom.secureelement.enabled", false);
 #endif
+
+// Allow control characters appear in composition string.
+// When this is false, control characters except
+// CHARACTER TABULATION (horizontal tab) are removed from
+// both composition string and data attribute of compositionupdate
+// and compositionend events.
+pref("dom.compositionevent.allow_control_characters", false);

widget/TextRange.h

@@ -174,6 +174,16 @@ struct TextRange
            mRangeType == aOther.mRangeType &&
            mRangeStyle == aOther.mRangeStyle;
   }
+
+  void RemoveCharacter(uint32_t aOffset)
+  {
+    if (mStartOffset > aOffset) {
+      --mStartOffset;
+      --mEndOffset;
+    } else if (mEndOffset > aOffset) {
+      --mEndOffset;
+    }
+  }
 };
 
 /******************************************************************************
@@ -223,6 +233,13 @@ public:
     }
     return true;
   }
+
+  void RemoveCharacter(uint32_t aOffset)
+  {
+    for (size_t i = 0, len = Length(); i < len; i++) {
+      ElementAt(i).RemoveCharacter(aOffset);
+    }
+  }
 };
 
 } // namespace mozilla

widget/tests/window_composition_text_querycontent.xul

@@ -3186,6 +3186,99 @@ function runNotRedundantChangeTest()
   textarea.removeEventListener("text", handler, true);
 }
 
+function runControlCharTest()
+{
+  textarea.focus();
+
+  var result = {};
+  function clearResult()
+  {
+    result = { compositionupdate: null, compositionend: null };
+  }
+
+  function handler(aEvent)
+  {
+    result[aEvent.type] = aEvent.data;
+  }
+
+  textarea.addEventListener("compositionupdate", handler, true);
+  textarea.addEventListener("compositionend", handler, true);
+
+  textarea.value = "";
+
+  var controlChars = String.fromCharCode.apply(null, Object.keys(Array.from({length:0x20}))) + "\x7F";
+  var allowedChars = "\t";
+
+  var data = "AB" + controlChars + "CD" + controlChars + "EF";
+  var removedData = "AB" + allowedChars + "CD" + allowedChars + "EF";
+
+  var DIndex = data.indexOf("D");
+  var removedDIndex = removedData.indexOf("D");
+
+  // input string contains control characters
+  clearResult();
+  synthesizeCompositionChange(
+    { "composition":
+      { "string": data,
+        "clauses":
+        [
+          { "length": DIndex,
+            "attr": COMPOSITION_ATTR_SELECTED_CLAUSE },
+          { "length": data.length - DIndex,
+            "attr": COMPOSITION_ATTR_CONVERTED_CLAUSE }
+        ]
+      },
+      "caret": { "start": DIndex, "length": 0 }
+    });
+
+  checkSelection(removedDIndex, "", "runControlCharTest", "#1")
+
+  is(result.compositionupdate, removedData, "runControlCharTest: control characters in event.data should be removed in compositionupdate event #1");
+  is(textarea.value, removedData, "runControlCharTest: control characters should not appear in textarea #1");
+
+  synthesizeComposition({ type: "compositioncommit", data: data });
+
+  is(result.compositionend, removedData, "runControlCharTest: control characters in event.data should be removed in compositionend event #2");
+  is(textarea.value, removedData, "runControlCharTest: control characters should not appear in textarea #2");
+
+  textarea.value = "";
+
+  clearResult();
+
+  SpecialPowers.setBoolPref("dom.compositionevent.allow_control_characters", true);
+
+  // input string contains control characters, allowing control characters
+  clearResult();
+  synthesizeCompositionChange(
+    { "composition":
+      { "string": data,
+        "clauses":
+        [
+          { "length": DIndex,
+            "attr": COMPOSITION_ATTR_SELECTED_CLAUSE },
+          { "length": data.length - DIndex,
+            "attr": COMPOSITION_ATTR_CONVERTED_CLAUSE }
+        ]
+      },
+      "caret": { "start": DIndex, "length": 0 }
+    });
+
+  checkSelection(DIndex - 1 + kLFLen, "", "runControlCharTest", "#3")
+
+  is(result.compositionupdate, data, "runControlCharTest: control characters in event.data should not be removed in compositionupdate event #3");
+  is(textarea.value, data.replace(/\r/g, "\n"), "runControlCharTest: control characters should appear in textarea #3");
+
+  synthesizeComposition({ type: "compositioncommit", data: data });
+
+  is(result.compositionend, data, "runControlCharTest: control characters in event.data should not be removed in compositionend event #4");
+  is(textarea.value, data.replace(/\r/g, "\n"), "runControlCharTest: control characters should appear in textarea #4");
+
+  SpecialPowers.clearUserPref("dom.compositionevent.allow_control_characters");
+
+  textarea.removeEventListener("compositionupdate", handler, true);
+  textarea.removeEventListener("compositionend", handler, true);
+}
+
 function runRemoveContentTest(aCallback)
 {
   var events = [];
@@ -3760,6 +3853,7 @@ function runTest()
   runIsComposingTest();
   runRedundantChangeTest();
   runNotRedundantChangeTest();
+  runControlCharTest();
   runAsyncForceCommitTest(function () {
     runRemoveContentTest(function () {
       runFrameTest();