From 2151df75cb8646381d3c4bf95379c8f568dcd9eb Mon Sep 17 00:00:00 2001
From: Leo Tenenbaum <pommicket@gmail.com>
Date: Fri, 19 Feb 2021 12:58:37 -0500
Subject: tags starting to work

---
 tags.c | 144 ++++++++++++++++++++++++++++++++++++++++++++++++-----------------
 1 file changed, 107 insertions(+), 37 deletions(-)

(limited to 'tags.c')

diff --git a/tags.c b/tags.c
index b1fac23..5d3fca5 100644
--- a/tags.c
+++ b/tags.c
@@ -1,33 +1,57 @@
-void tags_free(TagsFile *f) {
-	free(f->file_data);
-	arr_free(f->tags);
-	memset(f, 0, sizeof *f);
+static int tag_try(FILE *fp, char const *tag) {
+	if (ftell(fp) != 0) {
+		while (1) {
+			int c = getc(fp);
+			if (c == EOF || c == '\n')
+				break;
+		}
+	}
+	
+	size_t tag_len = strlen(tag);
+	if (!feof(fp)) {
+		char line[256];
+		long pos = ftell(fp);
+		if (fgets(line, sizeof line, fp)) {
+			fseek(fp, pos, SEEK_SET);
+			size_t len = strspn(line, "\t");
+			if (tag_len > len)
+				len = tag_len;
+			return strncmp(tag, line, len);
+		}
+	}
+	return -1;
 }
 
-void tags_read(Ted *ted, TagsFile *f) {
+bool tag_goto(Ted *ted, char const *tag) {
 	change_directory(ted->cwd);
 	Settings const *settings = &ted->settings;
 	char const *tags_filename = settings->tags_filename;
 	FILE *file = fopen(tags_filename, "rb");
-	tags_free(f);
-	if (file) {
-		fseek(file, 0, SEEK_END);
-		size_t file_size = (size_t)ftell(file);
-		fseek(file, 0, SEEK_SET);
-		char *file_data = ted_calloc(ted, file_size + 1, 1);
-		if (file_data) {
-			f->file_data = file_data;
-			fread(file_data, 1, file_size, file);
-			char *p = file_data;
-			while (1) {
-				// each line in the file is of the format:
+	fseek(file, 0, SEEK_END);
+	size_t file_size = (size_t)ftell(file);
+	
+	size_t lo = 0;
+	size_t hi = file_size;
+	bool success = false;
+	while (lo < hi) {
+		size_t mid = (lo + hi)/2;
+		fseek(file, (long)mid, SEEK_SET);
+		int cmp = tag_try(file, tag);
+		if (cmp > 0) {
+			lo = mid+1;
+		} else if (cmp < 0) {
+			hi = mid;
+		} else {
+			// we found it!
+			char tag_enty[1024];
+			if (fgets(tag_enty, sizeof tag_enty, file)) {
+			
+				// the tag is of the format:
 				// tag name\tfile name\taddress
 				// or
 				// tag name\tfile name\taddress;" additional information
 				
-				char *end = p + strcspn(p, "\n");
-				bool eof = *end == '\0';
-				char *name = p;
+				char *name = tag_enty;
 				char *name_end = strchr(name, '\t');
 				if (name_end) {
 					*name_end = '\0';
@@ -61,26 +85,72 @@ void tags_read(Ted *ted, TagsFile *f) {
 						if (address_end - address > 2 && address_end[-2] == ';' && address_end[-1] == '"') {
 							address_end[-2] = '\0';
 						}
-						Tag tag = {.name = name, .file = filename, .address = address};
-						arr_add(f->tags, tag);
+						assert(streq(name, tag));
+						char path[TED_PATH_MAX];
+						ted_full_path(ted, filename, path, sizeof path);
+						if (ted_open_file(ted, path)) {
+							TextBuffer *buffer = ted->active_buffer;
+							int line_number = atoi(address);
+							if (line_number > 0) {
+								// the tags file gives us a line number
+								BufferPos pos = {.line = (u32)line_number, .index = 0};
+								buffer_cursor_move_to_pos(buffer, pos);
+								success = true;
+							} else if (address[0] == '/') {
+								// the tags file gives us a pattern to look for
+								char *pattern = address + 1;
+								// the patterns seem to be always literal (not regex-y), except for ^ and $
+								bool start_anchored = false, end_anchored = false;
+								if (*pattern == '^') {
+									start_anchored = true;
+									++pattern;
+								}
+								char *dollar = strchr(pattern, '$');
+								if (dollar) {
+									end_anchored = true;
+									*dollar = '\0';
+								}
+								
+								String32 pattern32 = str32_from_utf8(pattern);
+								u32 options = PCRE2_LITERAL;
+								if (start_anchored) options |= PCRE2_ANCHORED;
+								if (end_anchored) options |= PCRE2_ENDANCHORED;
+								int error_code;
+								PCRE2_SIZE error_offset;
+								pcre2_code *code = pcre2_compile(pattern32.str, pattern32.len,
+									options, &error_code, &error_offset, NULL);
+								if (code) {
+									pcre2_match_data *match_data = pcre2_match_data_create(10, NULL);
+									if (match_data) {
+										for (u32 line_idx = 0; line_idx < buffer->nlines; ++line_idx) {
+											Line *line = &buffer->lines[line_idx];
+											int n = pcre2_match(code, line->str, line->len, 0, PCRE2_NOTEMPTY,
+												match_data, NULL);
+											if (n == 1) {
+												// found it!
+												PCRE2_SIZE *ovector = pcre2_get_ovector_pointer(match_data);
+												PCRE2_SIZE index = ovector[0];
+												BufferPos pos = {line_idx, (u32)index};
+												buffer_cursor_move_to_pos(buffer, pos);
+												buffer->center_cursor_next_frame = true;
+												break;
+											}
+										}
+										pcre2_match_data_free(match_data);
+									}
+									pcre2_code_free(code);
+								}
+								str32_free(&pattern32);
+							} else {
+								ted_seterr(ted, "Unrecognized tag address: %s", address);
+							}
+							break;
+						}
 					}
 				}
-				if (eof) break; // end of file
-				p = end + 1;
 			}
 		}
-		f->last_modified = time_last_modified(tags_filename);
-		fclose(file);
-	} else {
-		ted_seterr(ted, "tags file does not exist.");
 	}
+	fclose(file);
+	return success;
 }
-
-void tags_read_if_changed(Ted *ted, TagsFile *f) {
-	Settings const *settings = &ted->settings;
-	char const *tags_filename = settings->tags_filename;
-	struct timespec modify_time = time_last_modified(tags_filename);
-	if (!timespec_eq(modify_time, f->last_modified)) {
-		tags_read(ted, f);
-	}
-}
\ No newline at end of file
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