virfile: Introduce virFileRemoveLastComponent

Move some parts of virStorageFileRemoveLastPathComponent
into a separate function so they can be reused.

Signed-off-by: Michal Privoznik <mprivozn@redhat.com>

src/libvirt_private.syms

@@ -1517,6 +1517,7 @@ virFileReadHeaderFD;
 virFileReadLimFD;
 virFileRelLinkPointsTo;
 virFileRemove;
+virFileRemoveLastComponent;
 virFileResolveAllLinks;
 virFileResolveLink;
 virFileRewrite;

src/util/virfile.c

@@ -3132,6 +3132,23 @@ virFileSanitizePath(const char *path)
     return cleanpath;
 }
 
+/**
+ * virFileRemoveLastComponent:
+ *
+ * For given path cut off the last component. If there's no dir
+ * separator (whole path is one file name), @path is turned into
+ * an empty string.
+ */
+void
+virFileRemoveLastComponent(char *path)
+{
+    char *tmp;
+
+    if ((tmp = strrchr(path, VIR_FILE_DIR_SEPARATOR)))
+        tmp[1] = '\0';
+    else
+        path[0] = '\0';
+}
 
 /**
  * virFilePrintf:

src/util/virfile.h

@@ -268,6 +268,7 @@ bool virFileIsAbsPath(const char *path);
 int virFileAbsPath(const char *path,
                    char **abspath) ATTRIBUTE_RETURN_CHECK;
 const char *virFileSkipRoot(const char *path);
+void virFileRemoveLastComponent(char *path);
 
 int virFileOpenTty(int *ttymaster,
                    char **ttyName,

src/util/virstoragefile.c

@@ -2868,16 +2868,12 @@ virStorageFileCanonicalizePath(const char *path,
 static char *
 virStorageFileRemoveLastPathComponent(const char *path)
 {
-    char *tmp;
     char *ret;
 
     if (VIR_STRDUP(ret, path ? path : "") < 0)
         return NULL;
 
-    if ((tmp = strrchr(ret, '/')))
-        tmp[1] = '\0';
-    else
-        ret[0] = '\0';
+    virFileRemoveLastComponent(ret);
 
     return ret;
 }