From 07e1601cd54d9ca9ed0b8648597e8d332242d938 Mon Sep 17 00:00:00 2001
From: Kim Woelders <kim@woelders.dk>
Date: Sun, 1 Mar 2020 05:55:25 +0100
Subject: [PATCH] Reduce number of stat() calls during load

Also skip empty files entirely.
---
 src/lib/api.c   | 21 ++-------------------
 src/lib/file.c  |  2 +-
 src/lib/file.h  | 22 ++++++++++++++++++++++
 src/lib/image.c | 28 ++++++++++++++++++++++++++--
 4 files changed, 51 insertions(+), 22 deletions(-)

diff --git a/src/lib/api.c b/src/lib/api.c
index b65a04d..e94bebf 100644
--- a/src/lib/api.c
+++ b/src/lib/api.c
@@ -1412,26 +1412,9 @@ imlib_load_image_with_error_return(const char *file,
    CHECK_CONTEXT(ctx);
    CHECK_PARAM_POINTER_RETURN("imlib_load_image_with_error_return", "file",
                               file, NULL);
-   if (!__imlib_FileExists(file))
-     {
-        *error_return = IMLIB_LOAD_ERROR_FILE_DOES_NOT_EXIST;
-        return NULL;
-     }
-   if (__imlib_FileIsDir(file))
-     {
-        *error_return = IMLIB_LOAD_ERROR_FILE_IS_DIRECTORY;
-        return NULL;
-     }
-   if (!__imlib_FileCanRead(file))
-     {
-        *error_return = IMLIB_LOAD_ERROR_PERMISSION_DENIED_TO_READ;
-        return NULL;
-     }
    prev_ctxt_image = ctx->image;
-   im = (Imlib_Image) __imlib_LoadImage(file,
-                                        (ImlibProgressFunction)
-                                        ctx->progress_func,
-                                        ctx->progress_granularity, 1, 0, &er);
+   im = __imlib_LoadImage(file, (ImlibProgressFunction) ctx->progress_func,
+                          ctx->progress_granularity, 1, 0, &er);
    ctx->image = prev_ctxt_image;
    if (im)
       *error_return = IMLIB_LOAD_ERROR_NONE;
diff --git a/src/lib/file.c b/src/lib/file.c
index ef8eaa5..5616859 100644
--- a/src/lib/file.c
+++ b/src/lib/file.c
@@ -117,7 +117,7 @@ __imlib_FileExtension(const char *file)
    return *p != '\0' ? p : NULL;
 }
 
-static int
+int
 __imlib_FileStat(const char *file, struct stat *st)
 {
    if ((!file) || (!*file))
diff --git a/src/lib/file.h b/src/lib/file.h
index b5e1fc6..414ef7a 100644
--- a/src/lib/file.h
+++ b/src/lib/file.h
@@ -1,6 +1,8 @@
 #ifndef __FILE_H
 #define __FILE_H 1
 
+#include <sys/stat.h>
+
 #include "common.h"
 
 int                 __imlib_IsRealFile(const char *s);
@@ -9,6 +11,26 @@ char               *__imlib_FileRealFile(const char *file);
 
 const char         *__imlib_FileExtension(const char *file);
 
+int                 __imlib_FileStat(const char *file, struct stat *st);
+
+static inline       time_t
+__imlib_StatModDate(const struct stat *st)
+{
+   return (st->st_mtime > st->st_ctime) ? st->st_mtime : st->st_ctime;
+}
+
+static inline int
+__imlib_StatIsFile(const struct stat *st)
+{
+   return S_ISREG(st->st_mode);
+}
+
+static inline int
+__imlib_StatIsDir(const struct stat *st)
+{
+   return S_ISDIR(st->st_mode);
+}
+
 int                 __imlib_FileExists(const char *s);
 int                 __imlib_FileIsFile(const char *s);
 int                 __imlib_FileIsDir(const char *s);
diff --git a/src/lib/image.c b/src/lib/image.c
index 24cd1cc..2f343f9 100644
--- a/src/lib/image.c
+++ b/src/lib/image.c
@@ -526,6 +526,26 @@ __imlib_ErrorFromErrno(int err, int save)
      }
 }
 
+static int
+__imlib_FileCheck(const char *file, struct stat *st, ImlibLoadError * er)
+{
+   int                 err;
+
+   err = 0;
+
+   if (__imlib_FileStat(file, st))
+      err = IMLIB_LOAD_ERROR_FILE_DOES_NOT_EXIST;
+   else if (__imlib_StatIsDir(st))
+      err = IMLIB_LOAD_ERROR_FILE_IS_DIRECTORY;
+   else if (st->st_size == 0)
+      err = IMLIB_LOAD_ERROR_UNKNOWN;
+
+   if (er)
+      *er = err;
+
+   return err;
+}
+
 /* create a new image struct from data passed that is wize w x h then return */
 /* a pointer to that image sturct */
 ImlibImage         *
@@ -648,6 +668,7 @@ __imlib_LoadImage(const char *file, ImlibProgressFunction progress,
    ImlibLoader        *best_loader;
    int                 loader_ret;
    ImlibLdCtx          ilc;
+   struct stat         st;
 
    if (!file || file[0] == '\0')
       return NULL;
@@ -686,12 +707,15 @@ __imlib_LoadImage(const char *file, ImlibProgressFunction progress,
           }
      }
 
+   if (__imlib_FileCheck(file, &st, er))
+      return NULL;
+
    /* either image in cache is invalid or we dont even have it in cache */
    /* so produce a new one and load an image into that */
    im = __imlib_ProduceImage();
    im->file = strdup(file);
 
-   if (__imlib_IsRealFile(file))
+   if (__imlib_StatIsFile(&st))
      {
         im->real_file = im->file;
         im->key = NULL;
@@ -711,7 +735,7 @@ __imlib_LoadImage(const char *file, ImlibProgressFunction progress,
         return NULL;
      }
 
-   im->moddate = __imlib_FileModDate(im->real_file);
+   im->moddate = __imlib_StatModDate(&st);
 
    im->data_memory_func = imlib_context_get_image_data_memory_function();