tempfile.c: fix style issues and comments

src/nvim/tempfile.c

@@ -15,56 +15,50 @@
 # include "tempfile.c.generated.h"
 #endif
 
-/* Name of Vim's own temp dir. Ends in a slash. */
+/// Name of Vim's own temp dir. Ends in a slash.
 static char_u *vim_tempdir = NULL;
-static uint32_t temp_count = 0;             /* Temp filename counter. */
 
-/*
- * This will create a directory for private use by this instance of Vim.
- * This is done once, and the same directory is used for all temp files.
- * This method avoids security problems because of symlink attacks et al.
- * It's also a bit faster, because we only need to check for an existing
- * file when creating the directory and not for each temp file.
- */
+/// Create a directory for private use by this instance of Neovim.
+/// This is done once, and the same directory is used for all temp files.
+/// This method avoids security problems because of symlink attacks et al.
+/// It's also a bit faster, because we only need to check for an existing
+/// file when creating the directory and not for each temp file.
 static void vim_maketempdir(void)
 {
   static const char *temp_dirs[] = TEMP_DIR_NAMES;
-  int i;
-  /*
-   * Try the entries in `TEMP_DIR_NAMES` to create the temp directory.
-   */
+  // Try the entries in `TEMP_DIR_NAMES` to create the temp directory.
   char_u itmp[TEMP_FILE_PATH_MAXLEN];
-  for (i = 0; i < (int)(sizeof(temp_dirs) / sizeof(char *)); ++i) {
-    /* expand $TMP, leave room for "/nvimXXXXXX/999999999" */
+  for (size_t i = 0; i < sizeof(temp_dirs) / sizeof(char *); ++i) {
+    // Expand environment variables, leave room for "/nvimXXXXXX/999999999"
     expand_env((char_u *)temp_dirs[i], itmp, TEMP_FILE_PATH_MAXLEN - 22);
-    if (os_isdir(itmp)) {                    /* directory exists */
+    if (os_isdir(itmp)) {  // directory exists
       add_pathsep(itmp);
 
-      /* Leave room for filename */
+      // Concatenate with temporary directory name pattern
       STRCAT(itmp, "nvimXXXXXX");
-      if (os_mkdtemp((char *)itmp) != NULL)
+      if (os_mkdtemp((char *)itmp) != NULL) {
         vim_settempdir(itmp);
-      if (vim_tempdir != NULL)
+      }
+      if (vim_tempdir != NULL) {
         break;
       }
     }
   }
+}
 
-/*
- * Delete the temp directory and all files it contains.
- */
+/// Delete the temp directory and all files it contains.
 void vim_deltempdir(void)
 {
-  char_u      **files;
-  int file_count;
-  int i;
-
   if (vim_tempdir != NULL) {
     snprintf((char *)NameBuff, MAXPATHL, "%s*", vim_tempdir);
+
+    char_u **files;
+    int file_count;
     if (gen_expand_wildcards(1, &NameBuff, &file_count, &files,
         EW_DIR|EW_FILE|EW_SILENT) == OK) {
-      for (i = 0; i < file_count; ++i)
+      for (int i = 0; i < file_count; ++i) {
         os_remove((char *)files[i]);
+      }
       FreeWild(file_count, files);
     }
     path_tail(NameBuff)[-1] = NUL;
@@ -75,6 +69,8 @@ void vim_deltempdir(void)
   }
 }
 
+/// Get the name of temp directory. This directory would be created on the first
+/// call to this function.
 char_u *vim_gettempdir(void)
 {
   if (vim_tempdir == NULL) {
@@ -84,43 +80,44 @@ char_u *vim_gettempdir(void)
   return vim_tempdir;
 }
 
-/*
- * Directory "tempdir" was created.  Expand this name to a full path and put
- * it in "vim_tempdir".  This avoids that using ":cd" would confuse us.
- * "tempdir" must be no longer than MAXPATHL.
- */
+/// Set Neovim own temporary directory name to `tempdir`. This directory should
+/// be already created. Expand this name to a full path and put it in
+/// `vim_tempdir`. This avoids that using `:cd` would confuse us.
+///
+/// @param tempdir must be no longer than MAXPATHL.
 static void vim_settempdir(char_u *tempdir)
 {
   char_u *buf = verbose_try_malloc((size_t)MAXPATHL + 2);
   if (buf) {
-    if (vim_FullName(tempdir, buf, MAXPATHL, false) == FAIL)
+    if (vim_FullName(tempdir, buf, MAXPATHL, false) == FAIL) {
       STRCPY(buf, tempdir);
+    }
     add_pathsep(buf);
     vim_tempdir = vim_strsave(buf);
     free(buf);
   }
 }
 
-/*
- * vim_tempname(): Return a unique name that can be used for a temp file.
- *
- * The temp file is NOT created.
- *
- * The returned pointer is to allocated memory.
- * The returned pointer is NULL if no valid name was found.
- */
+/// Return a unique name that can be used for a temp file.
+///
+/// @note The temp file is NOT created.
+///
+/// @return pointer to the temp file name or NULL if Neovim can't create
+///         temporary directory for its own temporary files.
 char_u *vim_tempname(void)
 {
-  char_u itmp[TEMP_FILE_PATH_MAXLEN];
+  // Temp filename counter.
+  static uint32_t temp_count;
 
   char_u *tempdir = vim_gettempdir();
-  if (tempdir != NULL) {
-    /* There is no need to check if the file exists, because we own the
-     * directory and nobody else creates a file in it. */
+  if (!tempdir) {
+    return NULL;
+  }
+
+  // There is no need to check if the file exists, because we own the directory
+  // and nobody else creates a file in it.
+  char_u itmp[TEMP_FILE_PATH_MAXLEN];
   snprintf((char *)itmp, TEMP_FILE_PATH_MAXLEN,
            "%s%" PRIu32, tempdir, temp_count++);
   return vim_strsave(itmp);
 }
-
-  return NULL;
-}