mirror of
https://github.com/carbon-language/carbon-lang.git
synced 2026-10-01 22:02:45 +01:00
Richard Smith
9a33fc1673
We currently provide UTF-8 positions, since our source representation is UTF-8 and we use byte offsets as column numbers, but the LSP protocol default is UTF-16 column positions. Negotiate UTF-8 positions where possible; this is supported by essentially every LSP client other than VS Code. In the case where we select a UTF-16 position, we continue to not do any actual conversions, so our column offsets in such cases will continue to be wrong on non-ASCII source files in VS Code. Assisted by: Claude Code
51 lines
2.0 KiB
C++
51 lines
2.0 KiB
C++
// Part of the Carbon Language project, under the Apache License v2.0 with LLVM
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// Exceptions. See /LICENSE for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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#include <utility>
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#include "llvm/ADT/STLExtras.h"
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#include "toolchain/language_server/handle.h"
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namespace Carbon::LanguageServer {
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// Picks the encoding used to measure `Position::character` on the wire.
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// Use UTF-8 if offered, since Carbon source is natively UTF-8. Otherwise fall
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// back to UTF-16, to support VS Code and old LSP clients.
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static auto NegotiatePositionEncoding(
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const clang::clangd::ClientCapabilities& capabilities)
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-> clang::clangd::OffsetEncoding {
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if (capabilities.PositionEncodings &&
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llvm::is_contained(*capabilities.PositionEncodings,
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clang::clangd::OffsetEncoding::UTF8)) {
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return clang::clangd::OffsetEncoding::UTF8;
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}
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return clang::clangd::OffsetEncoding::UTF16;
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}
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auto HandleInitialize(
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Context& context, const clang::clangd::InitializeParams& params,
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llvm::function_ref<auto(llvm::Expected<llvm::json::Object>)->void> on_done)
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-> void {
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auto encoding = NegotiatePositionEncoding(params.capabilities);
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context.SetPositionEncoding(encoding);
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llvm::json::Object capabilities{{"documentSymbolProvider", true},
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{"textDocumentSync", /*Incremental=*/2},
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{"positionEncoding", encoding}};
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llvm::json::Object reply{{"capabilities", std::move(capabilities)}};
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on_done(reply);
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}
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// Implements `initialized`:
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// https://microsoft.github.io/language-server-protocol/specifications/lsp/3.17/specification/#initialized
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auto HandleInitialized(Context& /*context*/,
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const clang::clangd::NoParams& /*params*/) -> void {
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// Nothing to do, but every client sends this, so we handle it rather than
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// warning about an unsupported notification.
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// TODO: This is when we would use `client/registerCapability` for any
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// capabilities we want to register dynamically.
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}
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} // namespace Carbon::LanguageServer
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