[clangd] Check preceding char when completion triggers on ':' or '>'

Summary:
Only run completion when we were trigerred on '->' and '::', otherwise
send an error code in return.
To avoid automatically invoking completions in cases like 'a >^' or
'a ? b :^'.

Reviewers: hokein

Reviewed By: hokein

Subscribers: ioeric, MaskRay, jkorous, arphaman, kadircet, cfe-commits

Differential Revision: https://reviews.llvm.org/D55994

llvm-svn: 350304

1 files changed, 25 insertions, 0 deletions

diff --git a/clang-tools-extra/clangd/Protocol.h b/clang-tools-extra/clangd/Protocol.h
index 94838a8575a..17b69bde562 100644
--- a/clang-tools-extra/clangd/Protocol.h
+++ b/clang-tools-extra/clangd/Protocol.h
@@ -775,6 +775,31 @@ struct TextDocumentPositionParams {
 };
 bool fromJSON(const llvm::json::Value &, TextDocumentPositionParams &);
 
+enum class CompletionTriggerKind {
+  /// Completion was triggered by typing an identifier (24x7 code
+  /// complete), manual invocation (e.g Ctrl+Space) or via API.
+  Invoked = 1,
+  /// Completion was triggered by a trigger character specified by
+  /// the `triggerCharacters` properties of the `CompletionRegistrationOptions`.
+  TriggerCharacter = 2,
+  /// Completion was re-triggered as the current completion list is incomplete.
+  TriggerTriggerForIncompleteCompletions = 3
+};
+
+struct CompletionContext {
+  /// How the completion was triggered.
+  CompletionTriggerKind triggerKind = CompletionTriggerKind::Invoked;
+  /// The trigger character (a single character) that has trigger code complete.
+  /// Is undefined if `triggerKind !== CompletionTriggerKind.TriggerCharacter`
+  std::string triggerCharacter;
+};
+bool fromJSON(const llvm::json::Value &, CompletionContext &);
+
+struct CompletionParams : TextDocumentPositionParams {
+  CompletionContext context;
+};
+bool fromJSON(const llvm::json::Value &, CompletionParams &);
+
 enum class MarkupKind {
   PlainText,
   Markdown,