deal with LSP servers that don't support incremental sync

this was the problem with godot

5 files changed, 58 insertions, 33 deletions

diff --git a/buffer.c b/buffer.c
index 9fa4ee5..ac2b532 100644
--- a/buffer.c
+++ b/buffer.c
@@ -1909,7 +1909,38 @@ static void buffer_send_lsp_did_change(LSP *lsp, TextBuffer *buffer, BufferPos p
 	range.start = buffer_pos_to_lsp_position(buffer, pos);
 	BufferPos pos_end = buffer_pos_advance(buffer, pos, nchars_deleted);
 	range.end = buffer_pos_to_lsp_position(buffer, pos_end);
-	lsp_document_changed(lsp, buffer->path, range, new_text);
+	const char *document = buffer->path;
+
+	if (lsp->capabilities.incremental_sync_support) {
+		LSPRequest request = {.type = LSP_REQUEST_DID_CHANGE};
+		LSPDocumentChangeEvent change = {
+			.range = range,
+			.use_range = true,
+			.text = lsp_message_add_string32(&request.base, new_text),
+		};
+		LSPRequestDidChange *c = &request.data.change;
+		c->document = lsp_document_id(lsp, document);
+		arr_add(c->changes, change);
+		lsp_send_request(lsp, &request);
+	} else {
+		// re-send the whole document
+		// needed for servers which don't have incremental sync support,
+		// such as godot (at time of writing)
+		// this isn't great performance-wise,
+		// but we can't just send it each frame because then some
+		// requests might have messed up buffer positions from the server's point of view.
+		LSPRequest request = {.type = LSP_REQUEST_DID_CHANGE};
+		size_t len = buffer_contents_utf8(buffer, NULL);
+		LSPDocumentChangeEvent change = {
+			.use_range = false
+		};
+		char *text = lsp_message_alloc_string(&request.base, len, &change.text);
+		buffer_contents_utf8(buffer, text);
+		LSPRequestDidChange *c = &request.data.change;
+		c->document = lsp_document_id(lsp, document);
+		arr_add(c->changes, change);
+		lsp_send_request(lsp, &request);
+	}
 }
 
 BufferPos buffer_insert_text_at_pos(TextBuffer *buffer, BufferPos pos, String32 str) {
@@ -1932,9 +1963,7 @@ BufferPos buffer_insert_text_at_pos(TextBuffer *buffer, BufferPos pos, String32
 		// no text to insert
 		return pos;
 	}
-	
-	const u32 insertion_len = (u32)str.len;
-	
+
 	// create a copy of str. we need to do this to remove carriage returns and newlines in the case of line buffers
 	char32_t str_copy[256];
 	char32_t *str_alloc = NULL;
@@ -1968,10 +1997,7 @@ BufferPos buffer_insert_text_at_pos(TextBuffer *buffer, BufferPos pos, String32
 			autocomplete_close(buffer->ted);
 	}
 
-
-	LSP *lsp = buffer_lsp(buffer);
-	if (lsp)
-		buffer_send_lsp_did_change(lsp, buffer, pos, 0, str);
+	const String32 str_start = str; // keep this around for later
 
 	if (buffer->store_undo_events) {
 		BufferEdit *last_edit = arr_lastp(buffer->undo_history);
@@ -2054,12 +2080,18 @@ BufferPos buffer_insert_text_at_pos(TextBuffer *buffer, BufferPos pos, String32
 
 	BufferPos b = {.line = line_idx, .index = index};
 	free(str_alloc);
+
+	// we need to do this *after* making the change to the buffer
+	// because of how non-incremental syncing works.
+	LSP *lsp = buffer_lsp(buffer);
+	if (lsp)
+		buffer_send_lsp_did_change(lsp, buffer, pos, 0, str_start);
 	
 	const EditInfo info = {
 		.pos = pos,
 		.end = b,
 		.chars_deleted = 0,
-		.chars_inserted = insertion_len,
+		.chars_inserted = (u32)str_start.len,
 	};
 	// move diagnostics around as needed
 	arr_foreach_ptr(buffer->diagnostics, Diagnostic, d) {
@@ -2465,11 +2497,6 @@ void buffer_delete_chars_at_pos(TextBuffer *buffer, BufferPos pos, i64 nchars_)
 			autocomplete_close(buffer->ted);
 	}
 
-
-	LSP *lsp = buffer_lsp(buffer);
-	if (lsp)
-		buffer_send_lsp_did_change(lsp, buffer, pos, nchars, (String32){0});
-
 	if (buffer->store_undo_events) {
 		// we need to make sure the undo history keeps track of the edit.
 		// we will either combine it with the previous BufferEdit, or create a new
@@ -2581,6 +2608,12 @@ void buffer_delete_chars_at_pos(TextBuffer *buffer, BufferPos pos, i64 nchars_)
 	// cursor position could have been invalidated by this edit
 	buffer_validate_cursor(buffer);
 
+	// we need to do this *after* making the change to the buffer
+	// because of how non-incremental syncing works.
+	LSP *lsp = buffer_lsp(buffer);
+	if (lsp)
+		buffer_send_lsp_did_change(lsp, buffer, pos, deletion_len, (String32){0});
+
 	buffer_lines_modified(buffer, line_idx, line_idx);
 	signature_help_retrigger(buffer->ted);
 	
diff --git a/lsp-write.c b/lsp-write.c
index 050d784..0eed987 100644
--- a/lsp-write.c
+++ b/lsp-write.c
@@ -547,7 +547,8 @@ void write_request(LSP *lsp, LSPRequest *request) {
 				arr_foreach_ptr(change->changes, LSPDocumentChangeEvent, event) {
 					write_arr_elem(o);
 					write_obj_start(o);
-						write_key_range(o, "range", event->range);
+						if (event->use_range)
+							write_key_range(o, "range", event->range);
 						write_key_string(o, "text", lsp_request_string(request, event->text));
 					write_obj_end(o);
 				}
diff --git a/lsp.c b/lsp.c
index 025e2be..c828bf1 100644
--- a/lsp.c
+++ b/lsp.c
@@ -67,7 +67,7 @@ static LSPString lsp_message_add_json_string(LSPMessageBase *message, const JSON
 	json_string_get(json, string, dest, len + 1);
 	return ret;
 }
-static LSPString lsp_message_add_string32(LSPMessageBase *message, String32 string) {
+LSPString lsp_message_add_string32(LSPMessageBase *message, String32 string) {
 	LSPString ret = {0};
 	size_t len32 = string.len;
 	if (len32 == 0) {
@@ -438,7 +438,7 @@ static bool lsp_receive(LSP *lsp, size_t max_size) {
 	// kind of a hack. this is needed because arr_set_len zeroes the data.
 	arr_hdr_(lsp->received_data)->len = (u32)received_so_far;
 	lsp->received_data[received_so_far] = '\0';// null terminate
-	#if 0
+	#if LSP_SHOW_S2C
 	const int limit = 1000;
 	printf("%s%.*s%s%s\n",term_italics(stdout),limit,lsp->received_data,
 		strlen(lsp->received_data) > (size_t)limit ? "..." : "",
@@ -768,19 +768,6 @@ void lsp_free(LSP *lsp) {
 	free(lsp);
 }
 
-void lsp_document_changed(LSP *lsp, const char *document, LSPRange range, String32 new_text) {
-	// @TODO(optimization, eventually): batch changes (using the contentChanges array)
-	LSPRequest request = {.type = LSP_REQUEST_DID_CHANGE};
-	LSPDocumentChangeEvent change = {
-		.range = range,
-		.text = lsp_message_add_string32(&request.base, new_text),
-	};
-	LSPRequestDidChange *c = &request.data.change;
-	c->document = lsp_document_id(lsp, document);
-	arr_add(c->changes, change);
-	lsp_send_request(lsp, &request);
-}
-
 int lsp_position_cmp(LSPPosition a, LSPPosition b) {
 	if (a.line < b.line)
 		return -1;
diff --git a/lsp.h b/lsp.h
index 27f2706..8361f60 100644
--- a/lsp.h
+++ b/lsp.h
@@ -129,6 +129,8 @@ typedef struct {
 // see TextDocumentContentChangeEvent in the LSP spec
 typedef struct {
 	LSPRange range;
+	/// if `false`, \ref text refers to the whole document contents after the change.
+	bool use_range;
 	/// new text.
 	LSPString text;
 } LSPDocumentChangeEvent;
@@ -714,6 +716,7 @@ const char *lsp_request_string(const LSPRequest *request, LSPString string);
 /// sets `*string` to the LSPString, and returns a pointer which you can write the string to.
 /// the returned pointer will be zeroed up to and including [len].
 char *lsp_message_alloc_string(LSPMessageBase *message, size_t len, LSPString *string);
+LSPString lsp_message_add_string32(LSPMessageBase *message, String32 string);
 LSPString lsp_request_add_string(LSPRequest *request, const char *string);
 LSPString lsp_response_add_string(LSPResponse *response, const char *string);
 bool lsp_string_is_empty(LSPString string);
@@ -728,8 +731,6 @@ LSP *lsp_create(const char *root_dir, const char *command, u16 port, const char
 // if this fails (i.e. if the LSP does not have workspace support), create a new LSP
 // with root directory `new_root_dir`.
 bool lsp_try_add_root_dir(LSP *lsp, const char *new_root_dir);
-// report that this document has changed
-void lsp_document_changed(LSP *lsp, const char *document, LSPRange range, String32 new_text);
 // is this path in the LSP's workspace folders?
 bool lsp_covers_path(LSP *lsp, const char *path);
 // get next message from server
diff --git a/main.c b/main.c
index d1569f7..5deabac 100644
--- a/main.c
+++ b/main.c
@@ -1,6 +1,9 @@
 /*
 TODO:
-- figure out what's wrong with godot language server
+- figure out how to deal with godot language server being so slow
+  one comparatively solution is to wait x seconds before sending a batch of requests in the communication thread
+    (this gives us time to cancel the irrelevant requests before they get sent to the server,
+     and we can remove stale full-sync didChange requests)
 FUTURE FEATURES:
 - autodetect indentation (tabs vs spaces)
 - custom file/build command associations