Print log level even if STDERR is not a tty

Makes reading debug logs much easier, debug lines will start with `E`,
info lines with `I` and error lines with `E`.

1 files changed, 18 insertions, 5 deletions

diff --git a/common/log.c b/common/log.c
index af1bdc3f..6dc9d743 100644
--- a/common/log.c
+++ b/common/log.c
@@ -22,6 +22,12 @@ static const char *verbosity_colors[] = {
         [L_INFO  ] = "\x1B[1;34m",
         [L_DEBUG ] = "\x1B[1;30m",
 };
+static const char verbosity_chars[] = {
+        [L_SILENT] = '\0',
+        [L_ERROR ] = 'E',
+        [L_INFO  ] = 'I',
+        [L_DEBUG ] = 'D',
+};
 
 void init_log(log_importance_t verbosity) {
         if (verbosity != L_DEBUG) {
@@ -62,6 +68,16 @@ void _sway_vlog(const char *filename, int line, log_importance_t verbosity,
                 static struct tm *tm_info;
                 char buffer[26];
 
+                unsigned int c = verbosity;
+                if (c > sizeof(verbosity_colors) / sizeof(char *) - 1) {
+                        c = sizeof(verbosity_colors) / sizeof(char *) - 1;
+                }
+
+                // First, if not printing color, show the log level
+                if (!(colored && isatty(STDERR_FILENO)) && c != L_SILENT) {
+                        fprintf(stderr, "%c: ", verbosity_chars[c]);
+                }
+
                 // get current time
                 t = time(NULL);
                 // convert time to local time (determined by the locale)
@@ -70,11 +86,6 @@ void _sway_vlog(const char *filename, int line, log_importance_t verbosity,
                 strftime(buffer, sizeof(buffer), "%x %X - ", tm_info);
                 fprintf(stderr, "%s", buffer);
 
-                unsigned int c = verbosity;
-                if (c > sizeof(verbosity_colors) / sizeof(char *) - 1) {
-                        c = sizeof(verbosity_colors) / sizeof(char *) - 1;
-                }
-
                 if (colored && isatty(STDERR_FILENO)) {
                         fprintf(stderr, "%s", verbosity_colors[c]);
                 }
@@ -124,6 +135,8 @@ void sway_log_errno(log_importance_t verbosity, char* format, ...) {
 
                 if (colored && isatty(STDERR_FILENO)) {
                         fprintf(stderr, "%s", verbosity_colors[c]);
+                } else if (c != L_SILENT) {
+                        fprintf(stderr, "%c: ", verbosity_chars[c]);
                 }
 
                 va_list args;