utils: Load Xcursor themes using QFile

This improves the integration of the XcursorTheme class with the rest of
the Qt ecosystem, for example it should be possible to load cursor themes
from Qt resources.

src/3rdparty/xcursor.c

@@ -180,14 +180,6 @@ typedef struct _XcursorComment {
 #define XCURSOR_IMAGE_HEADER_LEN    (XCURSOR_CHUNK_HEADER_LEN + (5*4))
 #define XCURSOR_IMAGE_MAX_SIZE	    0x7fff	/* 32767x32767 max cursor size */
 
-typedef struct _XcursorFile XcursorFile;
-
-struct _XcursorFile {
-    void    *closure;
-    int	    (*read)  (XcursorFile *file, unsigned char *buf, int len);
-    int	    (*seek)  (XcursorFile *file, long offset, int whence);
-};
-
 typedef struct _XcursorComments {
     int		    ncomment;	/* number of comments */
     XcursorComment  **comments;	/* array of XcursorComment pointers */
@@ -256,7 +248,7 @@ XcursorImagesDestroy (XcursorImages *images)
 static XcursorBool
 _XcursorReadUInt (XcursorFile *file, XcursorUInt *u)
 {
-    unsigned char   bytes[4];
+    uint8_t   bytes[4];
 
     if (!file || !u)
         return XcursorFalse;
@@ -318,7 +310,7 @@ _XcursorReadFileHeader (XcursorFile *file)
 	return NULL;
     skip = head.header - XCURSOR_FILE_HEADER_LEN;
     if (skip)
-	if ((*file->seek) (file, skip, SEEK_CUR) == EOF)
+	if (!(*file->skip) (file, skip))
 	    return NULL;
     fileHeader = _XcursorFileHeaderCreate (head.ntoc);
     if (!fileHeader)
@@ -349,10 +341,9 @@ _XcursorSeekToToc (XcursorFile		*file,
 		   XcursorFileHeader	*fileHeader,
 		   int			toc)
 {
-    if (!file || !fileHeader || \
-        (*file->seek) (file, fileHeader->tocs[toc].position, SEEK_SET) == EOF)
-	return XcursorFalse;
-    return XcursorTrue;
+    if (!file || !fileHeader)
+        return XcursorFalse;
+    return (*file->seek) (file, fileHeader->tocs[toc].position);
 }
 
 static XcursorBool
@@ -498,7 +489,7 @@ _XcursorReadImage (XcursorFile		*file,
     return image;
 }
 
-static XcursorImages *
+XcursorImages *
 XcursorXcFileLoadImages (XcursorFile *file, int size)
 {
     XcursorFileHeader	*fileHeader;
@@ -544,42 +535,3 @@ XcursorXcFileLoadImages (XcursorFile *file, int size)
     }
     return images;
 }
-
-static int
-_XcursorStdioFileRead (XcursorFile *file, unsigned char *buf, int len)
-{
-    FILE    *f = file->closure;
-    return fread (buf, 1, len, f);
-}
-
-static int
-_XcursorStdioFileSeek (XcursorFile *file, long offset, int whence)
-{
-    FILE    *f = file->closure;
-    return fseek (f, offset, whence);
-}
-
-static void
-_XcursorStdioFileInitialize (FILE *stdfile, XcursorFile *file)
-{
-    file->closure = stdfile;
-    file->read = _XcursorStdioFileRead;
-    file->seek = _XcursorStdioFileSeek;
-}
-
-XcursorImages *
-XcursorFileLoadImages (const char *file, int size)
-{
-    XcursorFile	f;
-    XcursorImages *images;
-
-    FILE *fp = fopen(file, "r");
-    if (!fp)
-        return NULL;
-
-    _XcursorStdioFileInitialize (fp, &f);
-    images = XcursorXcFileLoadImages (&f, size);
-    fclose(fp);
-
-    return images;
-}

src/3rdparty/xcursor.h

@@ -57,8 +57,17 @@ typedef struct _XcursorImages {
     XcursorImage    **images;	/* array of XcursorImage pointers */
 } XcursorImages;
 
+typedef struct _XcursorFile XcursorFile;
+
+struct _XcursorFile {
+    void    *closure;
+    int	    (*read)  (XcursorFile *file, uint8_t *buf, int len);
+    XcursorBool     (*skip)  (XcursorFile *file, long offset);
+    XcursorBool	    (*seek)  (XcursorFile *file, long offset);
+};
+
 XcursorImages *
-XcursorFileLoadImages (const char *file, int size);
+XcursorXcFileLoadImages (XcursorFile *file, int size);
 
 void
 XcursorImagesDestroy (XcursorImages *images);

src/utils/xcursortheme.cpp

@@ -83,7 +83,28 @@ std::chrono::milliseconds KXcursorSprite::delay() const
 
 static QList<KXcursorSprite> loadCursor(const QString &filePath, int desiredSize, qreal devicePixelRatio)
 {
-    XcursorImages *images = XcursorFileLoadImages(QFile::encodeName(filePath), desiredSize * devicePixelRatio);
+    QFile file(filePath);
+    if (!file.open(QFile::ReadOnly)) {
+        return {};
+    }
+
+    XcursorFile reader {
+        .closure = &file,
+        .read = [](XcursorFile *file, uint8_t *buffer, int len) -> int {
+            QFile *device = static_cast<QFile *>(file->closure);
+            return device->read(reinterpret_cast<char *>(buffer), len);
+        },
+        .skip = [](XcursorFile *file, long offset) -> XcursorBool {
+            QFile *device = static_cast<QFile *>(file->closure);
+            return device->skip(offset) != -1;
+        },
+        .seek = [](XcursorFile *file, long offset) -> XcursorBool {
+            QFile *device = static_cast<QFile *>(file->closure);
+            return device->seek(offset);
+        },
+    };
+
+    XcursorImages *images = XcursorXcFileLoadImages(&reader, desiredSize * devicePixelRatio);
     if (!images) {
         return {};
     }