When ContentCacheInParent receives eCompositionStart, it temporarily sets mCompositionStart to selection start offset. However, if there is a composition in the remote process, the selection start is caret position in the composition string. Therefore, it's not useful information. Instead, the composition start offset should be used because around there are a lot of information.
For that, ContentCacheInParent should always store compostion start offset in the remote process with mCompositionStartInChild even if mWidgetHasComposition is false. And when it receives eCompositionStart, mCompositionStart should be set to mCompositionStartInChild.
MozReview-Commit-ID: DksPNEsi6Ec
If the remote process is busy or user restarts composition too quickly, there could be 2 or more compositions in ContentCache. For managing such case, ContentCacheInParent should manage the pending composition count which is increased at dispatching eCompositionStart event to the remote process and decreased at receiving eCompositionCommit(AsIs) event from the remote process.
MozReview-Commit-ID: KbTsK20NEZD
For making the meaning of ContentCacheInParent::mIsComposing clearer, let's rename it to mWidgetHasComposition. It becomes true when the parent process sends eCompositionStart to the remote process and false when the parent process sends eCompositionCommit(AsIs). So, it represents if the widget (i.e., the native IME handler in the chrome process) has composition.
MozReview-Commit-ID: 5k05IXMgJxw
ContentCache::TextRectArray's end offset is computed as start offset + its length. Therefore, end offset is the last offset in the range + 1. So, IsOverlappingWith() shouldn't return true only when end offset is overlapped with given range.
That means that when TextRectArray doesn't have rects, i.e., mRects is empty, IsOverlappingWith() always returns false. And when TextRectArray has one or more rects, IsOverlappingWith() should compare its range and given range without "=".
MozReview-Commit-ID: JxNPcEwikjR
This patch makes ContentCache store previous character's rect of selection anchor and selection focus because if caret is at end of a line, IME may query the last character of the line.
MozReview-Commit-ID: 5X1K8KtrYfl
This must be able to reproduce with some IMEs which creates 0 length composition string. In such case, mTextRectArray isn't available, but mTextRectArray.GetUnionRectAsFarAsPossible() always assumes that it's valid and has at least one rect. Therefore, it can meet this crash.
Therefore, this patch makes that ContentCacheInParent::GetUnionTextRects() not use mTextRectArray when it's not valid nor doesn't have rects.
MozReview-Commit-ID: 2yLMo4lxI3Z
ContentCache may store composition string's rects which are inserted by one or more older composition event. Even in such case, native IME, especially TIP of TSF, expects non-empty rects.
Therefore, if native IME handler uses "insertion point relative query", ContentCache should return non-empty rect as far as possible. For example, even if query offset or range is not in its rect array of composition string, ContentCache should adjust the offset into the stored range.
MozReview-Commit-ID: 7hcIqxOWFk2
