Add support for FILE_NAMES_ALIASES

Signed-off-by: Mattias Andrée <maandree@kth.se>

2 files changed, 97 insertions, 20 deletions

diff --git a/libfonts.h b/libfonts.h
index 779ea9e..242b187 100644
--- a/libfonts.h
+++ b/libfonts.h
@@ -48,6 +48,48 @@ enum libfonts_default_font {
 
 
 /**
+ * Alias font list file type
+ */
+enum libfonts_alias_line_type {
+	/**
+	 * Improperly formatted line
+	 */
+	LIBFONTS_ALIAS_LINE_MALFORMATTED,
+
+	/**
+	 * Empty or white-space only line
+	 */
+	LIBFONTS_ALIAS_LINE_BLANK,
+
+	/**
+	 * Comment line
+	 */
+	LIBFONTS_ALIAS_LINE_COMMENT,
+
+	/**
+	 * Alias definition line
+	 */
+	LIBFONTS_ALIAS_LINE_ALIAS_DEFINITION,
+
+	/**
+	 * Line containing just the string ”FILE_NAMES_ALIASES”
+	 * indicating that the file name, minus its suffix, of
+	 * each font file, in the same directory as the font alias
+	 * file, should be set as an alias for the font contained
+	 * in that file
+	 *
+	 * For example, if the director contains the files
+	 * "My Font.ttf" and "My Font Bold.ttf", the font names
+	 * "My Font" and "My Font Bold" should be aliases for the
+	 * two fonts, whose proper names are determined by their
+	 * content and ought to be listed in the file "fonts.dir"
+	 * in the same directory
+	 */
+	LIBFONTS_ALIAS_LINE_FONT_NAMES_ALIASES
+};
+
+
+/**
  * Antialiasing algorithm
  */
 enum libfonts_antialiasing {
@@ -1689,6 +1731,7 @@ int libfonts_get_font_root_dirs(char ***, size_t *, struct libfonts_context *);
  * and are located in any font directory, i.e. directories returned by
  * `libfonts_get_font_root_dirs` subdirectors (and further decedents)
  * 
+ * @param   typep   Output parameter fot the line's type
  * @param   aliasp  Output parameter for the new alias
  * @param   namep   Output parameter for the alias target,
  *                  which can be ether a proper XFDL (font name),
@@ -1697,17 +1740,16 @@ int libfonts_get_font_root_dirs(char ***, size_t *, struct libfonts_context *);
  *                  newline or NUL byte
  * @param   endp    Output parameter for the parsing end, i.e. the
  *                  first newline or NUL byte in `line`
- * @return          1 if the line included a font alias,
- *                  0 if the line was blank or a comment line,
- *                  -1 on failure
+ * @return          0 on success, -1 on failure
  * 
  * @throws  ENOMEM   Failed to allocate memory for `*aliasp` or `*namep`
- * @throws  EBADMSG  The line is malformatted
  * 
- * `*aliasp` and `*namep` are set to `NULL` unless the function
- * returns 1; `*endp` is updated even on failure
+ * Unless `*typep` is set to (or would be set to) `LIBFONTS_ALIAS_LINE_ALIAS_DEFINITION`,
+ * `*aliasp` and `*namep` are set to `NULL`. On failure, `*aliasp` and `*namep` are set
+ * to `NULL` and `*typep` is seto to `LIBFONTS_ALIAS_LINE_BLANK`. `*endp` is updated even
+ * on failure.
  */
-int libfonts_parse_alias_line(char **, char **, const char *, char **);
+int libfonts_parse_alias_line(enum libfonts_alias_line_type *, char **, char **, const char *, char **);
 
 /* TODO add font listing */
 
diff --git a/libfonts_parse_alias_line.c b/libfonts_parse_alias_line.c
index 453ea51..0496449 100644
--- a/libfonts_parse_alias_line.c
+++ b/libfonts_parse_alias_line.c
@@ -4,7 +4,7 @@
 
 
 static int
-read_field(char **valuep, const char *s, const char **endp)
+read_field(enum libfonts_alias_line_type *typep, char **valuep, const char *s, const char **endp)
 {
 	char end1 = ' ';
 	char end2 = '\t';
@@ -27,15 +27,15 @@ read_field(char **valuep, const char *s, const char **endp)
 			esc += 1;
 			s++;
 			if (!*s || *s == '\n')
-				goto ebadmsg;
+				goto badline;
 		}
 		s++;
 	}
 	end = s;
 	len = (size_t)(end - start) - esc;
 	if (end1 == '"' && *s != '"') {
-	ebadmsg:
-		errno = EBADMSG;
+	badline:
+		*typep = LIBFONTS_ALIAS_LINE_MALFORMATTED;
 		*endp = s;
 		return -1;
 	}
@@ -60,9 +60,25 @@ read_field(char **valuep, const char *s, const char **endp)
 	return 0;
 }
 
+static int
+is_file_names_aliases(const char *line, const char **endp)
+{
+	if (strncmp(line, "FILE_NAMES_ALIASES", sizeof("FILE_NAMES_ALIASES") - 1))
+		return 0;
+	line = &line[sizeof("FILE_NAMES_ALIASES") - 1];
+	while (isblank(*line))
+		line++;
+	if (!*line || *line == '\n') {
+		*endp = line;
+		return 1;
+	}
+	return 0;
+}
+
 int
-libfonts_parse_alias_line(char **aliasp, char **namep, const char *line, char **endp)
+libfonts_parse_alias_line(enum libfonts_alias_line_type *typep, char **aliasp, char **namep, const char *line, char **endp)
 {
+	enum libfonts_alias_line_type type = LIBFONTS_ALIAS_LINE_BLANK;
 	int ret = 0;
 
 	if (aliasp)
@@ -72,38 +88,57 @@ libfonts_parse_alias_line(char **aliasp, char **namep, const char *line, char **
 
 	while (isblank(*line))
 		line++;
-	if (!*line || *line == '!')
+	if (!*line)
+		goto out;
+	if (*line == '!') {
+		type = LIBFONTS_ALIAS_LINE_COMMENT;
 		goto out;
+	}
+
+	if (is_file_names_aliases(line, &line)) {
+		type = LIBFONTS_ALIAS_LINE_FONT_NAMES_ALIASES;
+		goto out;
+	}
 
-	if (read_field(aliasp, line, &line))
+	if (read_field(&type, aliasp, line, &line))
 		goto fail;
 
 	if (!isblank(*line))
-		goto ebadmsg;
+		goto badline;
 	do {
 		line++;
 	} while (isblank(*line));
 
-	if (read_field(namep, line, &line))
+	if (read_field(&type, namep, line, &line))
 		goto fail;
 
+	type = LIBFONTS_ALIAS_LINE_ALIAS_DEFINITION;
 	while (isblank(*line))
 		line++;
 	if (*line && *line != '\n')
-		goto ebadmsg;
+		goto badline;
 
-	ret = 1;
 	goto out;
 
-ebadmsg:
-	errno = EBADMSG;
+badline:
+	type = LIBFONTS_ALIAS_LINE_MALFORMATTED;
 fail:
+	if (aliasp) {
+		free(*aliasp);
+		*aliasp = NULL;
+	}
+	if (namep) {
+		free(*namep);
+		*namep = NULL;
+	}
 	ret = -1;
 	while (*line && *line != '\n')
 		line++;
 out:
 	if (endp)
 		*endp = *(char **)(void *)&line;
+	if (typep)
+		*typep = type;
 	return ret;
 }