c++-ify variable_substitute()

src/common.cc

@@ -152,60 +152,47 @@ FILE *open_file(const char *file, int *reported)
 	return fp;
 }
 
-void variable_substitute(const char *s, char *dest, unsigned int n)
+std::string variable_substitute(std::string s)
 {
-	while (*s && n > 1) {
-		if (*s == '$') {
-			s++;
-			if (*s != '$') {
-				char buf[256];
-				const char *a, *var;
-				unsigned int len;
+	std::string::size_type pos = 0;
+	while((pos = s.find('$', pos)) != std::string::npos) {
+		if(pos + 1 >= s.size())
+			break;
 
-				/* variable is either $foo or ${foo} */
-				if (*s == '{') {
-					s++;
-					a = s;
-					while (*s && *s != '}') {
-						s++;
-					}
-				} else {
-					a = s;
-					while (*s && (isalnum((int) *s) || *s == '_')) {
-						s++;
-					}
+		if(s[pos+1] == '$') {
+			s.erase(pos, 1);
+			++pos;
+		} else {
+			std::string var;
+			std::string::size_type l = 0;
+
+			if(isalpha(s[pos+1])) {
+				l = 1;
+				while(pos+l < s.size() && isalnum(s[pos+l]))
+					++l;
+				var = s.substr(pos+1, l-1);
+			} else if(s[pos+1] == '{') {
+				l = s.find('}', pos);
+				if(l == std::string::npos)
+					break;
+				l -= pos - 1;
+				var = s.substr(pos+2, l-3);
+			} else
+				++pos;
+
+			if(l) {
+				s.erase(pos, l);
+				const char *val = getenv(var.c_str());
+				if(val) {
+					s.insert(pos, val);
+					pos += strlen(val);
 				}
 
-				/* copy variable to buffer and look it up */
-				len = (s - a > 255) ? 255 : (s - a);
-				strncpy(buf, a, len);
-				buf[len] = '\0';
-
-				if (*s == '}') {
-					s++;
-				}
-
-				var = getenv(buf);
-
-				if (var) {
-					/* add var to dest */
-					len = strlen(var);
-					if (len >= n) {
-						len = n - 1;
-					}
-					strncpy(dest, var, len);
-					dest += len;
-					n -= len;
-				}
-				continue;
 			}
 		}
-
-		*dest++ = *s++;
-		n--;
 	}
 
-	*dest = '\0';
+	return s;
 }
 
 void format_seconds(char *buf, unsigned int n, long seconds)

src/common.h

@@ -67,7 +67,7 @@ double get_time(void);
 std::string to_real_path(const std::string &source);
 FILE *open_file(const char *file, int *reported);
 int open_fifo(const char *file, int *reported);
-void variable_substitute(const char *s, char *dest, unsigned int n);
+std::string variable_substitute(std::string s);
 
 void format_seconds(char *buf, unsigned int n, long t);
 void format_seconds_short(char *buf, unsigned int n, long t);

src/conky.cc

@@ -2795,11 +2795,9 @@ static void set_default_configurations(void)
 
 	free(current_mail_spool);
 	{
-		char buf[256];
-
-		variable_substitute(MAIL_FILE, buf, 256);
-		if (buf[0] != '\0') {
-			current_mail_spool = strndup(buf, text_buffer_size);
+		std::string buf = variable_substitute(MAIL_FILE);
+		if (not buf.empty()) {
+			current_mail_spool = strndup(buf.c_str(), text_buffer_size);
 		}
 	}
 
@@ -3461,13 +3459,11 @@ char load_config_file(const char *f)
 #endif /* BUILD_X11 */
 		CONF("mail_spool") {
 			if (value) {
-				char buffer[256];
+				std::string buffer = variable_substitute(value);
 
-				variable_substitute(value, buffer, 256);
-
-				if (buffer[0] != '\0') {
+				if (not buffer.empty()) {
 					free_and_zero(current_mail_spool);
-					current_mail_spool = strndup(buffer, text_buffer_size);
+					current_mail_spool = strndup(buffer.c_str(), text_buffer_size);
 				}
 			} else {
 				CONF_ERR;
@@ -4211,12 +4207,10 @@ void initialisation(int argc, char **argv) {
 
 #ifdef MAIL_FILE
 	if (current_mail_spool == NULL) {
-		char buf[256];
+		std::string buf = variable_substitute(MAIL_FILE);
 
-		variable_substitute(MAIL_FILE, buf, 256);
-
-		if (buf[0] != '\0') {
-			current_mail_spool = strndup(buf, text_buffer_size);
+		if (not buf.empty()) {
+			current_mail_spool = strndup(buf.c_str(), text_buffer_size);
 		}
 	}
 #endif

src/mail.cc

@@ -352,7 +352,7 @@ static void update_mail_count(struct local_mail_s *mail)
 void parse_local_mail_args(struct text_object *obj, const char *arg)
 {
 	float n1;
-	char mbox[256], dst[256];
+	char mbox[256];
 	struct local_mail_s *locmail;
 
 	if (!arg) {
@@ -370,11 +370,11 @@ void parse_local_mail_args(struct text_object *obj, const char *arg)
 		}
 	}
 
-	variable_substitute(mbox, dst, sizeof(dst));
+	std::string dst = variable_substitute(mbox);
 
 	locmail = (struct local_mail_s*)malloc(sizeof(struct local_mail_s));
 	memset(locmail, 0, sizeof(struct local_mail_s));
-	locmail->mbox = strndup(dst, text_buffer_size);
+	locmail->mbox = strndup(dst.c_str(), text_buffer_size);
 	locmail->interval = n1;
 	obj->data.opaque = locmail;
 }