[epiphany] view-source-handler: Get content from existing embed if possible

[Michael Catanzaro <mcatanzaro src gnome org>]

commit 8a3c6b12273e430468b2326c56392dee406d5e83
Author: Michael Catanzaro <mcatanzaro gnome org>
Date:   Mon Sep 12 13:33:57 2016 -0500

    view-source-handler: Get content from existing embed if possible
    
    Instead of always hitting the network to download the page again, first
    try to get the source from an existing web view that matches the URI to
    be displayed. Be careful to ignore the web view if it has a deferred
    load or hasn't finished loading yet.
    
    It's not perfect, in that it could get the source code from the wrong
    tab if two different tabs are displaying the same URI, but let not
    perfect be the enemy of the good.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=738475

 embed/ephy-view-source-handler.c |  114 ++++++++++++++++++++++++++++++++------
 1 files changed, 97 insertions(+), 17 deletions(-)
---
diff --git a/embed/ephy-view-source-handler.c b/embed/ephy-view-source-handler.c
index 4e58ce0..d177035 100644
--- a/embed/ephy-view-source-handler.c
+++ b/embed/ephy-view-source-handler.c
@@ -21,7 +21,9 @@
 #include "config.h"
 #include "ephy-view-source-handler.h"
 
+#include "ephy-embed-container.h"
 #include "ephy-embed-shell.h"
+#include "ephy-web-view.h"
 
 #include <gio/gio.h>
 #include <string.h>
@@ -47,13 +49,11 @@ ephy_view_source_request_new (EphyViewSourceHandler  *handler,
                               WebKitURISchemeRequest *request)
 {
   EphyViewSourceRequest *view_source_request;
-  EphyEmbedShell *shell = ephy_embed_shell_get_default ();
-  WebKitWebContext *context = ephy_embed_shell_get_web_context (shell);
 
   view_source_request = g_slice_new (EphyViewSourceRequest);
   view_source_request->source_handler = handler;
   view_source_request->scheme_request = g_object_ref (request);
-  view_source_request->web_view = g_object_ref_sink (webkit_web_view_new_with_context (context));
+  view_source_request->web_view = NULL; /* created only if required */
   view_source_request->cancellable = g_cancellable_new ();
   view_source_request->load_changed_id = 0;
 
@@ -67,7 +67,7 @@ ephy_view_source_request_free (EphyViewSourceRequest *request)
     g_signal_handler_disconnect (request->web_view, request->load_changed_id);
 
   g_object_unref (request->scheme_request);
-  g_object_unref (request->web_view);
+  g_clear_object (&request->web_view);
 
   g_cancellable_cancel (request->cancellable);
   g_object_unref (request->cancellable);
@@ -140,17 +140,96 @@ web_resource_data_cb (WebKitWebResource     *resource,
 }
 
 static void
+ephy_view_source_request_begin_get_source_from_web_view (EphyViewSourceRequest *request,
+                                                         WebKitWebView         *web_view)
+{
+  WebKitWebResource *resource = webkit_web_view_get_main_resource (web_view);
+  g_assert (resource);
+  webkit_web_resource_get_data (resource,
+                                request->cancellable,
+                                (GAsyncReadyCallback)(web_resource_data_cb),
+                                request);
+}
+
+static void
 load_changed_cb (WebKitWebView         *web_view,
                  WebKitLoadEvent        load_event,
                  EphyViewSourceRequest *request)
 {
-  if (load_event == WEBKIT_LOAD_FINISHED) {
-    WebKitWebResource *resource = webkit_web_view_get_main_resource (web_view);
-    webkit_web_resource_get_data (resource,
-                                  request->cancellable,
-                                  (GAsyncReadyCallback)(web_resource_data_cb),
-                                  request);
-  }
+  if (load_event == WEBKIT_LOAD_FINISHED)
+    ephy_view_source_request_begin_get_source_from_web_view (request, web_view);
+}
+
+static void
+ephy_view_source_request_begin_get_source_from_uri (EphyViewSourceRequest *request,
+                                                    const char            *uri)
+{
+  EphyEmbedShell *shell = ephy_embed_shell_get_default ();
+  WebKitWebContext *context = ephy_embed_shell_get_web_context (shell);
+
+  request->web_view = WEBKIT_WEB_VIEW (g_object_ref_sink (webkit_web_view_new_with_context (context)));
+
+  g_assert(request->load_changed_id == 0);
+  request->load_changed_id = g_signal_connect (request->web_view, "load-changed",
+                                               G_CALLBACK (load_changed_cb),
+                                               request);
+
+  webkit_web_view_load_uri (request->web_view, uri);
+}
+
+static gint
+web_view_is_displaying_matching_uri (EphyEmbed *embed,
+                                     SoupURI   *uri)
+{
+  EphyWebView *web_view;
+  SoupURI *view_uri;
+  gint ret = -1;
+
+  if (ephy_embed_has_load_pending (embed))
+    return -1;
+
+  web_view = ephy_embed_get_web_view (embed);
+  if (ephy_web_view_is_loading (web_view))
+    return -1;
+
+  view_uri = soup_uri_new (ephy_web_view_get_address (web_view));
+  if (!view_uri)
+    return -1;
+
+  soup_uri_set_fragment (view_uri, NULL);
+  ret = soup_uri_equal (view_uri, uri) ? 0 : -1;
+
+  soup_uri_free (view_uri);
+
+  return ret;
+}
+
+static WebKitWebView *
+get_web_view_matching_uri (SoupURI *uri)
+{
+  EphyEmbedShell *shell;
+  GtkWindow *window;
+  GList *embeds = NULL;
+  GList *found;
+  EphyEmbed *embed = NULL;
+
+  shell = ephy_embed_shell_get_default ();
+  window = gtk_application_get_active_window (GTK_APPLICATION (shell));
+
+  if (!EPHY_IS_EMBED_CONTAINER (window))
+    goto out;
+
+  embeds = ephy_embed_container_get_children (EPHY_EMBED_CONTAINER (window));
+  found = g_list_find_custom (embeds, uri, (GCompareFunc)web_view_is_displaying_matching_uri);
+
+  if (found)
+    embed = found->data;
+
+out:
+  g_list_free (embeds);
+  if (!embed)
+    return NULL;
+  return WEBKIT_WEB_VIEW (ephy_embed_get_web_view (embed));
 }
 
 static void
@@ -160,6 +239,7 @@ ephy_view_source_request_start (EphyViewSourceRequest *request)
   char *modified_uri;
   char *decoded_fragment;
   const char *original_uri;
+  WebKitWebView *web_view;
 
   request->source_handler->outstanding_requests =
       g_list_prepend (request->source_handler->outstanding_requests, request);
@@ -179,13 +259,13 @@ ephy_view_source_request_start (EphyViewSourceRequest *request)
   soup_uri_set_scheme (soup_uri, decoded_fragment);
   soup_uri_set_fragment (soup_uri, NULL);
   modified_uri = soup_uri_to_string (soup_uri, FALSE);
+  g_assert (modified_uri);
 
-  g_assert(request->load_changed_id == 0);
-  request->load_changed_id = g_signal_connect (request->web_view, "load-changed",
-                                               G_CALLBACK (load_changed_cb),
-                                               request);
-
-  webkit_web_view_load_uri (request->web_view, modified_uri);
+  web_view = get_web_view_matching_uri (soup_uri);
+  if (web_view)
+    ephy_view_source_request_begin_get_source_from_web_view (request, WEBKIT_WEB_VIEW (web_view));
+  else
+    ephy_view_source_request_begin_get_source_from_uri (request, modified_uri);
 
   g_free (decoded_fragment);
   g_free (modified_uri);