mg_file_write -> mg_file_printf

docs/README.md

@@ -1049,14 +1049,26 @@ size_t mg_file_size(const char *path);
 
 Return file size, or 0 on failure. Empty files also report 0 length.
 
-
 ### mg\_file\_write()
 
 ```c
-int mg_file_write(const char *path, const char *fmt, ...);
+bool mg_file_write(const char *path, const void *buf, size_t len);
 ```
 
-Write into a file `path` using `printf()` semantics. Return number of bytes written.
+Write data to a file, return `true` if written, `false` otherwise.
+The write is atomic, i.e. data gets written to a temporary file first,
+then `rename()-ed` to a destination file name.
+
+
+### mg\_file\_printf()
+
+```c
+int mg_file_printf(const char *path, const char *fmt, ...);
+```
+
+Write into a file `path` using `printf()` semantics.
+Return `true` on success, `false` otherwise. This function prints data to
+a temporary in-memory buffer first, then calls `mg_file_write()`.
 
 
 ### mg\_random()

mongoose.c

@@ -282,7 +282,9 @@ static void dns_cb(struct mg_connection *c, int ev, void *ev_data,
         if (d->c->is_resolving) {
           d->c->is_resolving = 0;
           if (dm.resolved) {
+#if MG_ENABLE_LOG
             char buf[100];
+#endif
             dm.addr.port = d->c->peer.port;  // Save port
             d->c->peer = dm.addr;            // Copy resolved address
             LOG(LL_DEBUG, ("%lu %s resolved to %s", d->c->id, dm.name,
@@ -3738,22 +3740,36 @@ char *mg_file_read(const char *path) {
   return data;
 }
 
-int mg_file_write(const char *path, const char *fmt, ...) {
-  char tmp[100];
-  int written = 0;
+bool mg_file_write(const char *path, const void *buf, size_t len) {
+  bool result = false;
   FILE *fp;
+  char tmp[PATH_MAX];
   snprintf(tmp, sizeof(tmp), "%s.%d", path, rand());
   fp = fopen(tmp, "wb");
   if (fp != NULL) {
-    va_list ap;
-    va_start(ap, fmt);
-    written = vfprintf(fp, fmt, ap);
-    va_end(ap);
+    result = fwrite(buf, 1, len, fp) == len;
     fclose(fp);
-    remove(path);
-    rename(tmp, path);
+    if (result) {
+      remove(path);
+      rename(tmp, path);
+    } else {
+      remove(tmp);
+    }
   }
-  return written;
+  return result;
+}
+
+bool mg_file_printf(const char *path, const char *fmt, ...) {
+  char tmp[256], *buf = tmp;
+  bool result;
+  size_t len;
+  va_list ap;
+  va_start(ap, fmt);
+  len = mg_vasprintf(&buf, sizeof(tmp), fmt, ap);
+  va_end(ap);
+  result = mg_file_write(path, buf, len);
+  if (buf != tmp) free(buf);
+  return result;
 }
 
 void mg_random(void *buf, size_t len) {

mongoose.h

@@ -16,7 +16,7 @@
 // license, as set out in <https://www.cesanta.com/license>.
 
 #pragma once
-#define MG_VERSION "7.1"
+#define MG_VERSION "7.2"
 
 
 #define MG_ARCH_CUSTOM 0
@@ -414,7 +414,8 @@ void mg_timer_poll(unsigned long uptime_ms);
 
 char *mg_file_read(const char *path);
 size_t mg_file_size(const char *path);
-int mg_file_write(const char *path, const char *fmt, ...);
+bool mg_file_write(const char *path, const void *buf, size_t len);
+bool mg_file_printf(const char *path, const char *fmt, ...);
 void mg_random(void *buf, size_t len);
 bool mg_globmatch(const char *pattern, int plen, const char *s, int n);
 bool mg_next_comma_entry(struct mg_str *s, struct mg_str *k, struct mg_str *v);

src/dns.c

@@ -156,7 +156,9 @@ static void dns_cb(struct mg_connection *c, int ev, void *ev_data,
         if (d->c->is_resolving) {
           d->c->is_resolving = 0;
           if (dm.resolved) {
+#if MG_ENABLE_LOG
             char buf[100];
+#endif
             dm.addr.port = d->c->peer.port;  // Save port
             d->c->peer = dm.addr;            // Copy resolved address
             LOG(LL_DEBUG, ("%lu %s resolved to %s", d->c->id, dm.name,

src/util.c

@@ -29,22 +29,36 @@ char *mg_file_read(const char *path) {
   return data;
 }
 
-int mg_file_write(const char *path, const char *fmt, ...) {
-  char tmp[100];
-  int written = 0;
+bool mg_file_write(const char *path, const void *buf, size_t len) {
+  bool result = false;
   FILE *fp;
+  char tmp[PATH_MAX];
   snprintf(tmp, sizeof(tmp), "%s.%d", path, rand());
   fp = fopen(tmp, "wb");
   if (fp != NULL) {
-    va_list ap;
-    va_start(ap, fmt);
-    written = vfprintf(fp, fmt, ap);
-    va_end(ap);
+    result = fwrite(buf, 1, len, fp) == len;
     fclose(fp);
-    remove(path);
-    rename(tmp, path);
+    if (result) {
+      remove(path);
+      rename(tmp, path);
+    } else {
+      remove(tmp);
+    }
   }
-  return written;
+  return result;
+}
+
+bool mg_file_printf(const char *path, const char *fmt, ...) {
+  char tmp[256], *buf = tmp;
+  bool result;
+  size_t len;
+  va_list ap;
+  va_start(ap, fmt);
+  len = mg_vasprintf(&buf, sizeof(tmp), fmt, ap);
+  va_end(ap);
+  result = mg_file_write(path, buf, len);
+  if (buf != tmp) free(buf);
+  return result;
 }
 
 void mg_random(void *buf, size_t len) {

src/util.h

@@ -5,7 +5,8 @@
 
 char *mg_file_read(const char *path);
 size_t mg_file_size(const char *path);
-int mg_file_write(const char *path, const char *fmt, ...);
+bool mg_file_write(const char *path, const void *buf, size_t len);
+bool mg_file_printf(const char *path, const char *fmt, ...);
 void mg_random(void *buf, size_t len);
 bool mg_globmatch(const char *pattern, int plen, const char *s, int n);
 bool mg_next_comma_entry(struct mg_str *s, struct mg_str *k, struct mg_str *v);

test/unit_test.c

@@ -1045,12 +1045,16 @@ static void test_dns(void) {
 }
 
 static void test_util(void) {
-  char buf[100], *s = mg_hexdump("abc", 3);
+  char buf[100], *s = mg_hexdump("abc", 3), *p;
   struct mg_addr a;
   ASSERT(s != NULL);
   free(s);
   memset(&a, 0, sizeof(a));
-  ASSERT(mg_file_write("data.txt", "%s", "hi") == 2);
+  ASSERT(mg_file_printf("data.txt", "%s", "hi") == true);
+  ASSERT((p = mg_file_read("data.txt")) != NULL);
+  ASSERT(strcmp(p, "hi") == 0);
+  free(p);
+  remove("data.txt");
   ASSERT(mg_aton(mg_str("0"), &a) == false);
   ASSERT(mg_aton(mg_str("0.0.0."), &a) == false);
   ASSERT(mg_aton(mg_str("0.0.0.256"), &a) == false);