summaryrefslogtreecommitdiff
path: root/lsp-write.c
blob: 79c1dd9428c4ad5780d2c2facbbd42cae57256f1 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
// writing messages to the LSP server

#define LSP_INTERNAL 1
#include "lsp.h"
#include "util.h"

#define write_bool lsp_write_bool // prevent naming conflict

static const char *lsp_language_id(Language lang) {
	switch (lang) {
	case LANG_CONFIG:
	case LANG_TED_CFG:
	case LANG_TEXT:
	case LANG_NONE:
		return "text";
	case LANG_C:
		return "c";
	case LANG_CPP:
		return "cpp";
	case LANG_JAVA:
		return "java";
	case LANG_JAVASCRIPT:
		return "javascript";
	case LANG_JSON:
		return "json";
	case LANG_TYPESCRIPT:
		return "typescript";
	case LANG_MARKDOWN:
		return "markdown";
	case LANG_GO:
		return "go";
	case LANG_RUST:
		return "rust";
	case LANG_PYTHON:
		return "python";
	case LANG_HTML:
		return "html";
	case LANG_TEX:
		return "latex";
	case LANG_XML:
		return "xml";
	case LANG_GLSL:
		// not specified as of LSP 3.17, but this seems like the natural choice
		return "glsl";
	case LANG_COUNT: break;
	}
	assert(0);
	return "text";
}

typedef struct {
	LSP *lsp;
	StrBuilder builder;
	bool is_first;
} JSONWriter;

static JSONWriter json_writer_new(LSP *lsp) {
	return (JSONWriter){
		.lsp = lsp,
		.builder = str_builder_new(),
		.is_first = true
	};
}

static void write_obj_start(JSONWriter *o) {
	str_builder_append(&o->builder, "{");
	o->is_first = true;
}

static void write_obj_end(JSONWriter *o) {
	str_builder_append(&o->builder, "}");
	o->is_first = false;
}

static void write_arr_start(JSONWriter *o) {
	str_builder_append(&o->builder, "[");
	o->is_first = true;
}

static void write_arr_end(JSONWriter *o) {
	str_builder_append(&o->builder, "]");
	o->is_first = false;
}

static void write_arr_elem(JSONWriter *o) {
	if (o->is_first) {
		o->is_first = false;
	} else {
		str_builder_append(&o->builder, ",");
	}
}

static void write_escaped(JSONWriter *o, const char *string) {
	StrBuilder *b = &o->builder;
	size_t output_index = str_builder_len(b);
	size_t capacity = 2 * strlen(string) + 1;
	// append a bunch of null bytes which will hold the escaped string
	str_builder_append_null(b, capacity);
	char *out = str_builder_get_ptr(b, output_index);
	// do the escaping
	size_t length = json_escape_to(out, capacity, string);
	// shrink down to just the escaped text
	str_builder_shrink(&o->builder, output_index + length);
}

static void write_string(JSONWriter *o, const char *string) {
	str_builder_append(&o->builder, "\"");
	write_escaped(o, string);
	str_builder_append(&o->builder, "\"");
}

static void write_key(JSONWriter *o, const char *key) {
	// NOTE: no keys in the LSP spec need escaping.
	str_builder_appendf(&o->builder, "%s\"%s\":", o->is_first ? "" : ",", key);
	o->is_first = false;
}

static void write_key_obj_start(JSONWriter *o, const char *key) {
	write_key(o, key);
	write_obj_start(o);
}

static void write_key_arr_start(JSONWriter *o, const char *key) {
	write_key(o, key);
	write_arr_start(o);
}

static void write_arr_elem_obj_start(JSONWriter *o) {
	write_arr_elem(o);
	write_obj_start(o);
}

static void write_arr_elem_arr_start(JSONWriter *o) {
	write_arr_elem(o);
	write_arr_start(o);
}

static void write_number(JSONWriter *o, double number) {
	str_builder_appendf(&o->builder, "%g", number);
}

static void write_key_number(JSONWriter *o, const char *key, double number) {
	write_key(o, key);
	write_number(o, number);
}

static void write_arr_elem_number(JSONWriter *o, double number) {
	write_arr_elem(o);
	write_number(o, number);
}

static void write_null(JSONWriter *o) {
	str_builder_append(&o->builder, "null");
}

static void write_key_null(JSONWriter *o, const char *key) {
	write_key(o, key);
	write_null(o);
}

static void write_bool(JSONWriter *o, bool b) {
	str_builder_append(&o->builder, b ? "true" : "false");
}

static void write_key_bool(JSONWriter *o, const char *key, bool b) {
	write_key(o, key);
	write_bool(o, b);
}

static void write_arr_elem_null(JSONWriter *o) {
	write_arr_elem(o);
	write_null(o);
}

static void write_key_string(JSONWriter *o, const char *key, const char *s) {
	write_key(o, key);
	write_string(o, s);
}

static void write_arr_elem_string(JSONWriter *o, const char *s) {
	write_arr_elem(o);
	write_string(o, s);
}

static void write_file_uri(JSONWriter *o, LSPDocumentID document) {
	const char *path = lsp_document_path(o->lsp, document);
	str_builder_append(&o->builder, "\"file://");
	#if _WIN32
		// why the fuck is there another slash it makes no goddamn sense
		str_builder_append(&o->builder, "/");
	#endif
	for (const char *p = path; *p; ++p) {
		char c = *p;
		#if _WIN32
		// file URIs use slashes: https://en.wikipedia.org/wiki/File_URI_scheme
		if (c == '\\') c = '/';
		#endif
		
		// see https://www.rfc-editor.org/rfc/rfc3986#page-12
		// these are the only allowed un-escaped characters in URIs
		bool escaped = !(
			   (c >= '0' && c <= '9')
			|| (c >= 'a' && c <= 'z')
			|| (c >= 'A' && c <= 'Z')
			|| c == '_' || c == '-' || c == '.' || c == '~' || c == '/'
			#if _WIN32
			|| c == ':' // i dont think you're supposed to escape the : in C:\...
			#endif
			);
		if (escaped) {
			str_builder_appendf(&o->builder, "%%%02x", (uint8_t)c);
		} else {
			str_builder_appendf(&o->builder, "%c", c);
		}
	}
	str_builder_append(&o->builder, "\"");
}

static void write_key_file_uri(JSONWriter *o, const char *key, LSPDocumentID document) {
	write_key(o, key);
	write_file_uri(o, document);
}

static void write_position(JSONWriter *o, LSPPosition position) {
	write_obj_start(o);
		write_key_number(o, "line", (double)position.line);
		write_key_number(o, "character", (double)position.character);
	write_obj_end(o);
}

static void write_key_position(JSONWriter *o, const char *key, LSPPosition position) {
	write_key(o, key);
	write_position(o, position);
}

static void write_range(JSONWriter *o, LSPRange range) {
	write_obj_start(o);
		write_key_position(o, "start", range.start);
		write_key_position(o, "end", range.end);
	write_obj_end(o);
}

static void write_key_range(JSONWriter *o, const char *key, LSPRange range) {
	write_key(o, key);
	write_range(o, range);
}

static void write_workspace_folder(JSONWriter *o, LSPDocumentID folder) {
	write_obj_start(o);
		write_key_file_uri(o, "uri", folder);
		write_key_string(o, "name", lsp_document_path(o->lsp, folder));
	write_obj_end(o);
}

static void write_workspace_folders(JSONWriter *o, LSPDocumentID *workspace_folders) {
	write_arr_start(o);
		arr_foreach_ptr(workspace_folders, LSPDocumentID, folder) {
			write_arr_elem(o);
			write_workspace_folder(o, *folder);
		}
	write_arr_end(o);
}

static void write_document_position(JSONWriter *o, LSPDocumentPosition pos) {
	write_key_obj_start(o, "textDocument");
		write_key_file_uri(o, "uri", pos.document);
	write_obj_end(o);
	write_key_position(o, "position", pos.pos);
}

static const char *lsp_request_method(LSPRequest *request) {
	switch (request->type) {
	case LSP_REQUEST_NONE: break;
	case LSP_REQUEST_INITIALIZE:
		return "initialize";
	case LSP_REQUEST_INITIALIZED:
		return "initialized";
	case LSP_REQUEST_SHUTDOWN:
		return "shutdown";
	case LSP_REQUEST_EXIT:
		return "exit";
	case LSP_REQUEST_CANCEL:
		return "$/cancelRequest";
	case LSP_REQUEST_SHOW_MESSAGE:
		return "window/showMessage";
	case LSP_REQUEST_LOG_MESSAGE:
		return "window/logMessage";
	case LSP_REQUEST_DID_OPEN:
		return "textDocument/didOpen";
	case LSP_REQUEST_DID_CLOSE:
		return "textDocument/didClose";
	case LSP_REQUEST_DID_CHANGE:
		return "textDocument/didChange";
	case LSP_REQUEST_COMPLETION:
		return "textDocument/completion";
	case LSP_REQUEST_SIGNATURE_HELP:
		return "textDocument/signatureHelp";
	case LSP_REQUEST_HOVER:
		return "textDocument/hover";
	case LSP_REQUEST_REFERENCES:
		return "textDocument/references";
	case LSP_REQUEST_DEFINITION:
		return "textDocument/definition";
	case LSP_REQUEST_DECLARATION:
		return "textDocument/declaration";
	case LSP_REQUEST_TYPE_DEFINITION:
		return "textDocument/typeDefinition";
	case LSP_REQUEST_IMPLEMENTATION:
		return "textDocument/implementation";
	case LSP_REQUEST_HIGHLIGHT:
		return "textDocument/documentHighlight";
	case LSP_REQUEST_RENAME:
		return "textDocument/rename";
	case LSP_REQUEST_WORKSPACE_FOLDERS:
		return "workspace/workspaceFolders";
	case LSP_REQUEST_DID_CHANGE_WORKSPACE_FOLDERS:
		return "workspace/didChangeWorkspaceFolders";
	case LSP_REQUEST_CONFIGURATION:
		return "workspace/didChangeConfiguration";
	case LSP_REQUEST_WORKSPACE_SYMBOLS:
		return "workspace/symbol";
	}
	assert(0);
	return "$/ignore";
}

static const size_t max_header_size = 64;
static JSONWriter message_writer_new(LSP *lsp) {
	JSONWriter writer = json_writer_new(lsp);
	// this is where our header will go
	str_builder_append_null(&writer.builder, max_header_size);
	return writer;	
}

static void message_writer_write_and_free(LSP *lsp, JSONWriter *o) {
	StrBuilder builder = o->builder;
	
	// this is kind of hacky but it lets us send the whole request with one write call.
	// probably not *actually* needed. i thought it would help fix an error but it didn't.
	size_t content_length = str_builder_len(&builder) - max_header_size;
	char header_str[64];
	sprintf(header_str, "Content-Length: %zu\r\n\r\n", content_length);
	size_t header_size = strlen(header_str);
	char *content = &builder.str[max_header_size - header_size];
	memcpy(content, header_str, header_size);
	
	#if LSP_SHOW_C2S
		printf("%s%s%s\n",term_bold(stdout),content,term_clear(stdout));
	#endif
	if (lsp->log) {
		fprintf(lsp->log, "LSP MESSAGE FROM CLIENT TO SERVER\n%s\n\n", content + header_size);
	}
	
	process_write(lsp->process, content, strlen(content));

	str_builder_free(&builder);
}

static void write_symbol_tag_support(JSONWriter *o) {
	write_key_obj_start(o, "tagSupport");
		write_key_arr_start(o, "valueSet");
			for (int i = LSP_SYMBOL_TAG_MIN; i <= LSP_SYMBOL_TAG_MAX; ++i)
				write_arr_elem_number(o, i);
		write_arr_end(o);
	write_obj_end(o);
}


static void write_completion_item_kind_support(JSONWriter *o) {
	// "completion item kinds" supported by ted
	// (these are the little icons displayed for function/variable/etc.)
	write_key_obj_start(o, "completionItemKind");
		write_key_arr_start(o, "valueSet");
			for (int i = LSP_COMPLETION_KIND_MIN;
				i <= LSP_COMPLETION_KIND_MAX; ++i) {
				write_arr_elem_number(o, i);
			}
		write_arr_end(o);
	write_obj_end(o);
}

static void write_symbol_kind_support(JSONWriter *o) {
	write_key_obj_start(o, "symbolKind");
		write_key_arr_start(o, "valueSet");
			for (int i = LSP_SYMBOL_KIND_MIN;
				i <= LSP_SYMBOL_KIND_MAX;
				++i) {
				write_arr_elem_number(o, i);
			}
		write_arr_end(o);
	write_obj_end(o);
}

// NOTE: don't call lsp_request_free after calling this function.
//  I will do it for you.
void write_request(LSP *lsp, LSPRequest *request) {
	JSONWriter writer = message_writer_new(lsp);
	JSONWriter *o = &writer;
	
	write_obj_start(o);
	write_key_string(o, "jsonrpc", "2.0");
	
	if (request->id) { // i.e. if this is a request as opposed to a notification
		write_key_number(o, "id", request->id);
	}
	write_key_string(o, "method", lsp_request_method(request));
	
	switch (request->type) {
	case LSP_REQUEST_NONE:
	// these are server-to-client-only requests
	case LSP_REQUEST_SHOW_MESSAGE:
	case LSP_REQUEST_LOG_MESSAGE:
	case LSP_REQUEST_WORKSPACE_FOLDERS:
		assert(0);
		break;
	case LSP_REQUEST_SHUTDOWN:
	case LSP_REQUEST_EXIT:
		// no params
		break;
	case LSP_REQUEST_INITIALIZED:
		write_key_obj_start(o, "params");
		write_obj_end(o);
		break;
	case LSP_REQUEST_INITIALIZE: {
		write_key_obj_start(o, "params");
			write_key_number(o, "processId", process_get_id());
			write_key_obj_start(o, "capabilities");
				// here are the client capabilities for ted
				write_key_obj_start(o, "textDocument");
					write_key_obj_start(o, "completion");
						// completion capabilities
						write_key_obj_start(o, "completionItem");
							write_key_bool(o, "snippetSupport", false);
							write_key_bool(o, "commitCharactersSupport", false);
							write_key_arr_start(o, "documentationFormat");
								// we dont really support markdown
								write_arr_elem_string(o, "plaintext");
							write_arr_end(o);
							write_key_bool(o, "deprecatedSupport", true);
							write_key_bool(o, "preselectSupport", false);
							write_symbol_tag_support(o);
							write_key_bool(o, "insertReplaceSupport", false);
						write_obj_end(o);
						write_completion_item_kind_support(o);
						write_key_bool(o, "contextSupport", true);
					write_obj_end(o);
					
					// signature help capabilities
					write_key_obj_start(o, "signatureHelp");
						write_key_obj_start(o, "signatureInformation");
							write_key_obj_start(o, "parameterInformation");
								write_key_bool(o, "labelOffsetSupport", true);
							write_obj_end(o);
							write_key_bool(o, "activeParameterSupport", true);
						write_obj_end(o);
						// we don't have context support because sending the activeSignatureHelp member is annoying
						//write_key_bool(o, "contextSupport", true);
					write_obj_end(o);
					
					// hover capabilities
					write_key_obj_start(o, "hover");
						write_key_arr_start(o, "contentFormat");
							write_arr_elem_string(o, "plaintext");
						write_arr_end(o);
					write_obj_end(o);
					
					// definition capabilities
					write_key_obj_start(o, "definition");
						// NOTE: LocationLink support doesn't seem useful to us right now.
					write_obj_end(o);
				write_obj_end(o);
				write_key_obj_start(o, "workspace");
					write_key_bool(o, "workspaceFolders", true);
					write_key_obj_start(o, "workspaceEdit");
						write_key_bool(o, "documentChanges", true);
						write_key_arr_start(o, "resourceOperations");
							write_arr_elem_string(o, "create");
							write_arr_elem_string(o, "rename");
							write_arr_elem_string(o, "delete");
						write_arr_end(o);
					write_obj_end(o);
					write_key_obj_start(o, "symbol");
						write_symbol_kind_support(o);
						write_symbol_tag_support(o);
						// resolve is kind of a pain to implement. i'm not doing it yet.
					write_obj_end(o);
				write_obj_end(o);
			write_obj_end(o);
			SDL_LockMutex(lsp->workspace_folders_mutex);
			write_key_file_uri(o, "rootUri", lsp->workspace_folders[0]);
			write_key(o, "workspaceFolders");
			write_workspace_folders(o, lsp->workspace_folders);
			SDL_UnlockMutex(lsp->workspace_folders_mutex);
			write_key_obj_start(o, "clientInfo");
				write_key_string(o, "name", "ted");
			write_obj_end(o);
		write_obj_end(o);
	} break;
	case LSP_REQUEST_CANCEL: {
		const LSPRequestCancel *cancel = &request->data.cancel;
		write_key_obj_start(o, "params");
			write_key_number(o, "id", cancel->id);
		write_obj_end(o);
	} break;
	case LSP_REQUEST_DID_OPEN: {
		const LSPRequestDidOpen *open = &request->data.open;
		write_key_obj_start(o, "params");
			write_key_obj_start(o, "textDocument");
				write_key_file_uri(o, "uri", open->document);
				write_key_string(o, "languageId", lsp_language_id(open->language));
				write_key_number(o, "version", 0);
				write_key_string(o, "text", open->file_contents);
			write_obj_end(o);
		write_obj_end(o);
	} break;
	case LSP_REQUEST_DID_CLOSE: {
		const LSPRequestDidClose *close = &request->data.close;
		write_key_obj_start(o, "params");
			write_key_obj_start(o, "textDocument");
				write_key_file_uri(o, "uri", close->document);
			write_obj_end(o);
		write_obj_end(o);
	} break;
	case LSP_REQUEST_DID_CHANGE: {
		LSPRequestDidChange *change = &request->data.change;
		SDL_LockMutex(lsp->document_mutex);
			assert(change->document < arr_len(lsp->document_data));
			LSPDocumentData *document = &lsp->document_data[change->document];
			u32 version = ++document->version_number;
		SDL_UnlockMutex(lsp->document_mutex);
		
		write_key_obj_start(o, "params");
			write_key_obj_start(o, "textDocument");
				write_key_number(o, "version", version);
				write_key_file_uri(o, "uri", change->document);
			write_obj_end(o);
			write_key_arr_start(o, "contentChanges");
				arr_foreach_ptr(change->changes, LSPDocumentChangeEvent, event) {
					write_arr_elem(o);
					write_obj_start(o);
						write_key_range(o, "range", event->range);
						write_key_string(o, "text", event->text ? event->text : "");
					write_obj_end(o);
				}
			write_arr_end(o);
		write_obj_end(o);
	} break;
	case LSP_REQUEST_COMPLETION: {
		const LSPRequestCompletion *completion = &request->data.completion;
		write_key_obj_start(o, "params");
			write_document_position(o, completion->position);
			const LSPCompletionContext *context = &completion->context;
			LSPCompletionTriggerKind trigger_kind = context->trigger_kind;
			if (trigger_kind != LSP_TRIGGER_NONE) {
				write_key_obj_start(o, "context");
					write_key_number(o, "triggerKind", trigger_kind);
					if (trigger_kind == LSP_TRIGGER_CHARACTER)
						write_key_string(o, "triggerCharacter", context->trigger_character);
				write_obj_end(o);
			}
		write_obj_end(o);
	} break;
	case LSP_REQUEST_SIGNATURE_HELP: {
		const LSPRequestSignatureHelp *help = &request->data.signature_help;
		write_key_obj_start(o, "params");
			write_document_position(o, help->position);
		write_obj_end(o);
	} break;
	case LSP_REQUEST_HOVER: {
		const LSPRequestHover *hover = &request->data.hover;
		write_key_obj_start(o, "params");
			write_document_position(o, hover->position);
		write_obj_end(o);
	} break;
	case LSP_REQUEST_DEFINITION:
	case LSP_REQUEST_DECLARATION:
	case LSP_REQUEST_TYPE_DEFINITION:
	case LSP_REQUEST_IMPLEMENTATION: {
		const LSPRequestDefinition *def = &request->data.definition;
		write_key_obj_start(o, "params");
			write_document_position(o, def->position);
		write_obj_end(o);
	} break;
	case LSP_REQUEST_HIGHLIGHT: {
		const LSPRequestHighlight *hl = &request->data.highlight;
		write_key_obj_start(o, "params");
			write_document_position(o, hl->position);
		write_obj_end(o);
	} break;
	case LSP_REQUEST_REFERENCES: {
		const LSPRequestReferences *refs = &request->data.references;
		write_key_obj_start(o, "params");
			write_document_position(o, refs->position);
			write_key_obj_start(o, "context");
				// why is this includeDeclaration thing which has nothing to do with context
				// why is it in an object called context
				// there's no other members of the ReferenceContext interface. just this.
				// why, LSP, why
				write_key_bool(o, "includeDeclaration", refs->include_declaration);
			write_obj_end(o);
		write_obj_end(o);
	} break;
	case LSP_REQUEST_RENAME: {
		const LSPRequestRename *rename = &request->data.rename;
		write_key_obj_start(o, "params");
			write_document_position(o, rename->position);
			write_key_string(o, "newName", rename->new_name);
		write_obj_end(o);
	} break;
	case LSP_REQUEST_WORKSPACE_SYMBOLS: {
		const LSPRequestWorkspaceSymbols *syms = &request->data.workspace_symbols;
		write_key_obj_start(o, "params");
			write_key_string(o, "query", syms->query);
		write_obj_end(o);
	} break;
	case LSP_REQUEST_DID_CHANGE_WORKSPACE_FOLDERS: {
		const LSPRequestDidChangeWorkspaceFolders *w = &request->data.change_workspace_folders;
		write_key_obj_start(o, "params");
			write_key_obj_start(o, "event");
				write_key_arr_start(o, "added");
					arr_foreach_ptr(w->added, LSPDocumentID, added) {
						write_arr_elem(o);
						write_workspace_folder(o, *added);
					}
				write_arr_end(o);
				write_key_arr_start(o, "removed");
					arr_foreach_ptr(w->removed, LSPDocumentID, removed) {
						write_arr_elem(o);
						write_workspace_folder(o, *removed);
					}
				write_arr_end(o);
			write_obj_end(o);
		write_obj_end(o);
		} break;
	case LSP_REQUEST_CONFIGURATION: {
		const LSPRequestConfiguration *config = &request->data.configuration;
		write_key_obj_start(o, "params");
			write_key(o, "settings");
			str_builder_append(&o->builder, config->settings);
		write_obj_end(o);
		} break;
	}
	
	write_obj_end(o);
	
	message_writer_write_and_free(lsp, o);
	
	if (request->id) {
		SDL_LockMutex(lsp->messages_mutex);
		arr_add(lsp->requests_sent, *request);
		SDL_UnlockMutex(lsp->messages_mutex);
	} else {
		lsp_request_free(request);
	}
}

// NOTE: don't call lsp_response_free after calling this function.
//  I will do it for you.
static void write_response(LSP *lsp, LSPResponse *response) {
	
	JSONWriter writer = message_writer_new(lsp);
	JSONWriter *o = &writer;
	LSPRequest *request = &response->request;
	
	write_obj_start(o);
		if (request->id_string)
			write_key_string(o, "id", request->id_string);
		else
			write_key_number(o, "id", request->id);
		write_key_string(o, "jsonrpc", "2.0");
		write_key(o, "result");
		switch (response->request.type) {
		case LSP_REQUEST_WORKSPACE_FOLDERS:
			SDL_LockMutex(lsp->workspace_folders_mutex);
				write_workspace_folders(o, lsp->workspace_folders);
			SDL_UnlockMutex(lsp->workspace_folders_mutex);
			break;
		case LSP_REQUEST_SHOW_MESSAGE:
			write_null(o);
			break;
		default:
			// this is not a valid client-to-server response.
			assert(0);
			break;
		}
	write_obj_end(o);
	
	message_writer_write_and_free(lsp, o);
	lsp_response_free(response);
}

void write_message(LSP *lsp, LSPMessage *message) {
	switch (message->type) {
	case LSP_REQUEST:
		write_request(lsp, &message->u.request);
		break;
	case LSP_RESPONSE:
		write_response(lsp, &message->u.response);
		break;
	}
}

#undef write_bool