getAbsolutePath() moved into utils.c

src/util.c

@@ -405,6 +405,58 @@ void getRandomHexChars(char *p, unsigned int len) {
     fclose(fp);
 }
 
+/* Given the filename, return the absolute path as an SDS string, or NULL
+ * if it fails for some reason. Note that "filename" may be an absolute path
+ * already, this will be detected and handled correctly.
+ *
+ * The function does not try to normalize everything, but only the obvious
+ * case of one or more "../" appearning at the start of "filename"
+ * relative path. */
+sds getAbsolutePath(char *filename) {
+    char cwd[1024];
+    sds abspath;
+    sds relpath = sdsnew(filename);
+
+    relpath = sdstrim(relpath," \r\n\t");
+    if (relpath[0] == '/') return relpath; /* Path is already absolute. */
+
+    /* If path is relative, join cwd and relative path. */
+    if (getcwd(cwd,sizeof(cwd)) == NULL) {
+        sdsfree(relpath);
+        return NULL;
+    }
+    abspath = sdsnew(cwd);
+    if (sdslen(abspath) && abspath[sdslen(abspath)-1] != '/')
+        abspath = sdscat(abspath,"/");
+
+    /* At this point we have the current path always ending with "/", and
+     * the trimmed relative path. Try to normalize the obvious case of
+     * trailing ../ elements at the start of the path.
+     *
+     * For every "../" we find in the filename, we remove it and also remove
+     * the last element of the cwd, unless the current cwd is "/". */
+    while (sdslen(relpath) >= 3 &&
+           relpath[0] == '.' && relpath[1] == '.' && relpath[2] == '/')
+    {
+        relpath = sdsrange(relpath,3,-1);
+        if (sdslen(abspath) > 1) {
+            char *p = abspath + sdslen(abspath)-2;
+            int trimlen = 1;
+
+            while(*p != '/') {
+                p--;
+                trimlen++;
+            }
+            abspath = sdsrange(abspath,0,-(trimlen+1));
+        }
+    }
+
+    /* Finally glue the two parts together. */
+    abspath = sdscatsds(abspath,relpath);
+    sdsfree(relpath);
+    return abspath;
+}
+
 #ifdef UTIL_TEST_MAIN
 #include <assert.h>