[geary/wip/use-upstream-jsc-0.12: 2/3] Adjust to upstream javascriptcore-4.0 bindings

[Michael Gratton <mjog src gnome org>]

commit 0d966950a2cba888873cd3a7f4f42bb7a017dc6d
Author: Rico Tzschichholz <ricotz ubuntu com>
Date:   Mon Apr 23 19:56:18 2018 +0200

    Adjust to upstream javascriptcore-4.0 bindings

 .../conversation-viewer/conversation-web-view.vala |  2 +-
 src/client/util/util-webkit.vala                   | 10 ++++----
 src/client/web-process/web-process-extension.vala  | 17 +++++-------
 src/engine/util/util-js.vala                       | 30 +++++++++++++++-------
 4 files changed, 33 insertions(+), 26 deletions(-)
---
diff --git a/src/client/conversation-viewer/conversation-web-view.vala 
b/src/client/conversation-viewer/conversation-web-view.vala
index 588d39bd..d8512355 100644
--- a/src/client/conversation-viewer/conversation-web-view.vala
+++ b/src/client/conversation-viewer/conversation-web-view.vala
@@ -183,7 +183,7 @@ public class ConversationWebView : ClientWebView {
 
     private void on_deceptive_link_clicked(WebKit.JavascriptResult result) {
         try {
-            JS.GlobalContext context = result.get_global_context();
+            unowned JS.GlobalContext context = result.get_global_context();
             JS.Object details = WebKitUtil.to_object(result);
 
             uint reason = (uint) Geary.JS.to_number(
diff --git a/src/client/util/util-webkit.vala b/src/client/util/util-webkit.vala
index 319e28ad..cba9eaf2 100644
--- a/src/client/util/util-webkit.vala
+++ b/src/client/util/util-webkit.vala
@@ -18,8 +18,8 @@ namespace WebKitUtil {
      */
     public bool to_bool(WebKit.JavascriptResult result)
         throws Geary.JS.Error {
-        JS.GlobalContext context = result.get_global_context();
-        JS.Value value = result.get_value();
+        unowned JS.GlobalContext context = result.get_global_context();
+        unowned JS.Value value = result.get_value();
         if (!value.is_boolean(context)) {
             throw new Geary.JS.Error.TYPE("Result is not a JS Boolean object");
         }
@@ -59,12 +59,12 @@ namespace WebKitUtil {
      */
     public string as_string(WebKit.JavascriptResult result)
         throws Geary.JS.Error {
-        JS.GlobalContext context = result.get_global_context();
-        JS.Value js_str_value = result.get_value();
+        unowned JS.GlobalContext context = result.get_global_context();
+        unowned JS.Value js_str_value = result.get_value();
         JS.Value? err = null;
         JS.String js_str = js_str_value.to_string_copy(context, out err);
         Geary.JS.check_exception(context, err);
-        return Geary.JS.to_string_released(js_str);
+        return Geary.JS.to_string_released((owned) js_str);
     }
 
     /**
diff --git a/src/client/web-process/web-process-extension.vala 
b/src/client/web-process/web-process-extension.vala
index ee89139d..1f478a6c 100644
--- a/src/client/web-process/web-process-extension.vala
+++ b/src/client/web-process/web-process-extension.vala
@@ -87,10 +87,9 @@ public class GearyWebExtension : Object {
         bool should_load = false;
         WebKit.Frame frame = page.get_main_frame();
         // Explicit cast fixes build on s390x/ppc64. Bug 783882
-        JS.GlobalContext context = (JS.GlobalContext)
-            frame.get_javascript_global_context();
+        unowned JS.GlobalContext context = frame.get_javascript_global_context();
         try {
-            JS.Value ret = execute_script(
+            unowned JS.Value ret = execute_script(
                 context, "geary.allowRemoteImages", int.parse("__LINE__")
             );
             should_load = ret.to_boolean(context);
@@ -106,8 +105,7 @@ public class GearyWebExtension : Object {
     private void remote_image_load_blocked(WebKit.WebPage page) {
         WebKit.Frame frame = page.get_main_frame();
         // Explicit cast fixes build on s390x/ppc64. Bug 783882
-        JS.GlobalContext context = (JS.GlobalContext)
-            frame.get_javascript_global_context();
+        unowned JS.GlobalContext context = frame.get_javascript_global_context();
         try {
             execute_script(
                 context, "geary.remoteImageLoadBlocked();", int.parse("__LINE__")
@@ -123,8 +121,7 @@ public class GearyWebExtension : Object {
     private void selection_changed(WebKit.WebPage page) {
         WebKit.Frame frame = page.get_main_frame();
         // Explicit cast fixes build on s390x/ppc64. Bug 783882
-        JS.GlobalContext context = (JS.GlobalContext)
-            frame.get_javascript_global_context();
+        unowned JS.GlobalContext context = frame.get_javascript_global_context();
         try {
             execute_script(
                 context, "geary.selectionChanged();", int.parse("__LINE__")
@@ -136,20 +133,18 @@ public class GearyWebExtension : Object {
 
     // Return type is nullable as a workaround for Bug 778046, it will
     // never actually be null.
-    private JS.Value? execute_script(JS.Context context, string script, int line)
+    private unowned JS.Value? execute_script(JS.Context context, string script, int line)
     throws Geary.JS.Error {
         JS.String js_script = new JS.String.create_with_utf8_cstring(script);
         JS.String js_source = new JS.String.create_with_utf8_cstring("__FILE__");
         JS.Value? err = null;
         try {
-            JS.Value ret = context.evaluate_script(
+            unowned JS.Value ret = context.evaluate_script(
                 js_script, null, js_source, line, out err
             );
             Geary.JS.check_exception(context, err);
             return ret;
         } finally {
-            js_script.release();
-            js_source.release();
         }
     }
 
diff --git a/src/engine/util/util-js.vala b/src/engine/util/util-js.vala
index 4d224297..ea955e99 100644
--- a/src/engine/util/util-js.vala
+++ b/src/engine/util/util-js.vala
@@ -10,6 +10,16 @@
  */
 namespace Geary.JS {
 
+#if !VALA_0_42
+    // Workaround broken version of this in the vala bindings. See Bug
+    // 788113.
+    [CCode (cname = "JSStringGetUTF8CString")]
+    private extern size_t js_string_get_utf8_cstring(
+        global::JS.String js,
+        [CCode (array_length_type = "gsize")] char[] buffer
+    );
+#endif
+
     /**
      * Errors produced by functions in {@link Geary.JS}.
      */
@@ -72,7 +82,7 @@ namespace Geary.JS {
         global::JS.String js_str = value.to_string_copy(context, out err);
         Geary.JS.check_exception(context, err);
 
-        return Geary.JS.to_string_released(js_str);
+        return Geary.JS.to_string_released((owned) js_str);
     }
 
     /**
@@ -101,12 +111,15 @@ namespace Geary.JS {
     /**
      * Returns a JSC {@link JS.String} as a Vala {@link string}.
      */
-    public inline string to_string_released(global::JS.String js) {
-        int len = js.get_maximum_utf8_cstring_size();
-        string str = string.nfill(len, 0);
-        js.get_utf8_cstring(str, len);
-        js.release();
-        return str;
+    public inline string to_string_released(owned global::JS.String js) {
+        size_t len = js.get_maximum_utf8_cstring_size();
+        uint8[] str = new uint8[len];
+#if VALA_0_42
+        js.get_utf8_cstring(str);
+#else
+        js_string_get_utf8_cstring(js, (char[]) str);
+#endif
+        return (string) str;
     }
 
     /**
@@ -128,7 +141,6 @@ namespace Geary.JS {
         try {
             Geary.JS.check_exception(context, err);
         } finally {
-            js_name.release();
         }
         return prop;
     }
@@ -157,7 +169,7 @@ namespace Geary.JS {
 
             throw new Error.EXCEPTION(
                 "JS exception thrown [%s]: %s"
-                .printf(err_type.to_string(), to_string_released(err_str))
+                .printf(err_type.to_string(), to_string_released((owned) err_str))
             );
         }
     }