Add phantom.resolveRelativeUrl and phantom.fullyDecodeUrl.

These utility functions make it easier to work with encoded URLs.
See issues #12216 and #11035.

src/phantom.cpp

@@ -434,6 +434,19 @@ void Phantom::debugExit(int code)
     doExit(code);
 }
 
+QString Phantom::resolveRelativeUrl(QString url, QString base)
+{
+  QUrl u = QUrl::fromEncoded(url.toLatin1());
+  QUrl b = QUrl::fromEncoded(base.toLatin1());
+
+  return b.resolved(u).toEncoded();
+}
+
+QString Phantom::fullyDecodeUrl(QString url)
+{
+  return QUrl::fromEncoded(url.toLatin1()).toDisplayString();
+}
+
 // private slots:
 void Phantom::printConsoleMessage(const QString& message)
 {

src/phantom.h

@@ -174,6 +174,40 @@ public slots:
     void exit(int code = 0);
     void debugExit(int code = 0);
 
+    // URL utilities
+
+    /**
+     * Resolve a URL relative to a base.
+     */
+    QString resolveRelativeUrl(QString url, QString base);
+
+    /**
+     * Decode a URL to human-readable form.
+     * @param url The URL to be decoded.
+     *
+     * This operation potentially destroys information.  It should only be
+     * used when displaying URLs to the user, not when recording URLs for
+     * later processing.  Quoting http://qt-project.org/doc/qt-5/qurl.html:
+     *
+     *   _Full decoding_
+     *
+     *   This [operation] should be used with care, since there are
+     *   two conditions that cannot be reliably represented in the
+     *   returned QString. They are:
+     *
+     *   + Non-UTF-8 sequences: URLs may contain sequences of
+     *     percent-encoded characters that do not form valid UTF-8
+     *     sequences. Since URLs need to be decoded using UTF-8, any
+     *     decoder failure will result in the QString containing one or
+     *     more replacement characters where the sequence existed.
+     *
+     *   + Encoded delimiters: URLs are also allowed to make a
+     *     distinction between a delimiter found in its literal form and
+     *     its equivalent in percent-encoded form. This is most commonly
+     *     found in the query, but is permitted in most parts of the URL.
+     */
+    QString fullyDecodeUrl(QString url);
+
 signals:
     void aboutToExit(int code);
 

test/basics/url-utils.js

@@ -0,0 +1,16 @@
+// These are cursory tests; we assume the underlying Qt
+// features are properly tested elsewhere.
+
+test(function () {
+    assert_equals(
+        phantom.resolveRelativeUrl(
+            "../scripts/foo.js",
+            "http://example.com/topic/page.html"),
+        "http://example.com/scripts/foo.js");
+
+    assert_equals(
+        phantom.fullyDecodeUrl(
+        "https://ja.wikipedia.org/wiki/%E8%87%A8%E6%B5%B7%E5%AD%A6%E6%A0%A1"),
+        "https://ja.wikipedia.org/wiki/臨海学校");
+
+}, "resolveRelativeUrl and fullyDecodeUrl");