Summary:
The Language Server Protocol unfortunately mandates that locations in files
be represented by line/column pairs, where the "column" is actually an index
into the UTF-16-encoded text of the line.
(This is because VSCode is written in JavaScript, which is UTF-16-native).
Internally clangd treats source files at UTF-8, the One True Encoding, and
generally deals with byte offsets (though there are exceptions).
Before this patch, conversions between offsets and LSP Position pretended
that Position.character was UTF-8 bytes, which is only true for ASCII lines.
Now we examine the text to convert correctly (but don't actually need to
transcode it, due to some nice details of the encodings).
The updated functions in SourceCode are the blessed way to interact with
the Position.character field, and anything else is likely to be wrong.
So I also updated the other accesses:
- CodeComplete needs a "clang-style" line/column, with column in utf-8 bytes.
This is now converted via Position -> offset -> clang line/column
(a new function is added to SourceCode.h for the second conversion).
- getBeginningOfIdentifier skipped backwards in UTF-16 space, which is will
behave badly when it splits a surrogate pair. Skipping backwards in UTF-8
coordinates gives the lexer a fighting chance of getting this right.
While here, I clarified(?) the logic comments, fixed a bug with identifiers
containing digits, simplified the signature slightly and added a test.
This seems likely to cause problems with editors that have the same bug, and
treat the protocol as if columns are UTF-8 bytes. But we can find and fix those.
Reviewers: hokein
Subscribers: klimek, ilya-biryukov, ioeric, MaskRay, jkorous, cfe-commits
Differential Revision: https://reviews.llvm.org/D46035
llvm-svn: 331029
Summary:
This patch adds support for incremental document syncing, as described
in the LSP spec. The protocol specifies ranges in terms of Position (a
line and a character), and our drafts are stored as plain strings. So I
see two things that may not be super efficient for very large files:
- Converting a Position to an offset (the positionToOffset function)
requires searching for end of lines until we reach the desired line.
- When we update a range, we construct a new string, which implies
copying the whole document.
However, for the typical size of a C++ document and the frequency of
update (at which a user types), it may not be an issue. This patch aims
at getting the basic feature in, and we can always improve it later if
we find it's too slow.
Signed-off-by: Simon Marchi <simon.marchi@ericsson.com>
Reviewers: malaperle, ilya-biryukov
Reviewed By: ilya-biryukov
Subscribers: MaskRay, klimek, mgorny, ilya-biryukov, jkorous-apple, ioeric, cfe-commits
Differential Revision: https://reviews.llvm.org/D44272
llvm-svn: 328500
Sam McCall