print_file_contents: define parameter struct, use strncpy()

The list of parameters was getting too lengthy.

i3status.c

@@ -779,7 +779,17 @@ int main(int argc, char *argv[]) {
 
             CASE_SEC_TITLE("read_file") {
                 SEC_OPEN_MAP("read_file");
-                print_file_contents(json_gen, buffer, title, cfg_getstr(sec, "path"), cfg_getstr(sec, "format"), cfg_getstr(sec, "format_bad"), cfg_getint(sec, "max_characters"));
+                file_contents_ctx_t ctx = {
+                    .json_gen = json_gen,
+                    .buf = buffer,
+                    .buflen = sizeof(buffer),
+                    .title = title,
+                    .path = cfg_getstr(sec, "path"),
+                    .format = cfg_getstr(sec, "format"),
+                    .format_bad = cfg_getstr(sec, "format_bad"),
+                    .max_chars = cfg_getint(sec, "max_characters"),
+                };
+                print_file_contents(&ctx);
                 SEC_CLOSE_MAP;
             }
         }

include/i3status.h

@@ -175,6 +175,13 @@ extern char *pct_mark;
         }                                                                                     \
     } while (0)
 
+#define OUTPUT_FORMATTED                                             \
+    do {                                                             \
+        const size_t remaining = ctx->buflen - (outwalk - ctx->buf); \
+        strncpy(outwalk, formatted, remaining);                      \
+        outwalk += strlen(formatted);                                \
+    } while (0)
+
 /*
  * The "min_width" module option may either be defined as a string or a number.
  */
@@ -246,7 +253,19 @@ bool process_runs(const char *path);
 int volume_pulseaudio(uint32_t sink_idx, const char *sink_name);
 bool description_pulseaudio(uint32_t sink_idx, const char *sink_name, char buffer[MAX_SINK_DESCRIPTION_LEN]);
 bool pulse_initialize(void);
-void print_file_contents(yajl_gen json_gen, char *buffer, const char *title, const char *path, const char *format, const char *format_bad, const int max_chars);
+
+typedef struct {
+    yajl_gen json_gen;
+    char *buf;
+    size_t buflen;
+    const char *title;
+    const char *path;
+    const char *format;
+    const char *format_bad;
+    const int max_chars;
+} file_contents_ctx_t;
+
+void print_file_contents(file_contents_ctx_t *ctx);
 
 /* socket file descriptor for general purposes */
 extern int general_socket;

src/print_file_contents.c

@@ -14,27 +14,28 @@
 
 #define STRING_SIZE 10
 
-void print_file_contents(yajl_gen json_gen, char *buffer, const char *title, const char *path, const char *format, const char *format_bad, const int max_chars) {
-    const char *walk = format;
-    char *outwalk = buffer;
-    char *buf = scalloc(max_chars * sizeof(char) + 1);
+void print_file_contents(file_contents_ctx_t *ctx) {
+    const char *walk = ctx->format;
+    char *outwalk = ctx->buf;
+    char *buf = scalloc(ctx->max_chars * sizeof(char) + 1);
 
-    char *abs_path = resolve_tilde(path);
+    char *abs_path = resolve_tilde(ctx->path);
     int fd = open(abs_path, O_RDONLY);
     free(abs_path);
 
-    INSTANCE(path);
+#define json_gen ctx->json_gen
+    INSTANCE(ctx->path);
 
     int n = -1;
     if (fd > -1) {
-        n = read(fd, buf, max_chars);
+        n = read(fd, buf, ctx->max_chars);
         if (n != -1) {
             buf[n] = '\0';
         }
         (void)close(fd);
         START_COLOR("color_good");
     } else if (errno != 0) {
-        walk = format_bad;
+        walk = ctx->format_bad;
         START_COLOR("color_bad");
     }
 
@@ -53,18 +54,19 @@ void print_file_contents(yajl_gen json_gen, char *buffer, const char *title, con
     sprintf(string_errno, "%d", errno);
 
     placeholder_t placeholders[] = {
-        {.name = "%title", .value = title},
+        {.name = "%title", .value = ctx->title},
         {.name = "%content", .value = buf},
         {.name = "%errno", .value = string_errno},
         {.name = "%error", .value = strerror(errno)}};
 
     const size_t num = sizeof(placeholders) / sizeof(placeholder_t);
     char *formatted = format_placeholders(walk, &placeholders[0], num);
-    strcpy(outwalk, formatted);
-    outwalk += strlen(formatted);
+
+    OUTPUT_FORMATTED;
+
     free(formatted);
     free(buf);
 
     END_COLOR;
-    OUTPUT_FULL_TEXT(buffer);
+    OUTPUT_FULL_TEXT(ctx->buf);
 }