[evolution] Fix various issues with clipboard content handling

[Tomas Popela <tpopela src gnome org>]

commit daadd7a18361fdf934d9204b11c79230b5f40059
Author: Tomas Popela <tpopela redhat com>
Date:   Wed Nov 30 08:59:48 2016 +0100

    Fix various issues with clipboard content handling
    
     * Prefer image content over the text/* one.
     * In HTML mode before trying to save the image from the clipboard (to be
       later inserted into the editor) save the clipboard's text/* content as
       if we fail to save the image (not necessary by our fault - looks like
       the current web engines (WebKitGTK+, Gecko) have some problems
       copying the IMG element with SRCSET attribute - see [0]). If this
       fails then the source application can cancel the content and we could
       not fallback to at least some content.
     * Mark editor as changed when an image is inserted.
    
    Reported as https://bugzilla.redhat.com/show_bug.cgi?id=1307205
    
    [0] - https://bugzilla.redhat.com/show_bug.cgi?id=1307205#c10

 src/composer/e-msg-composer.c               |   22 +++---
 src/modules/webkit-editor/e-webkit-editor.c |  106 ++++++++++++---------------
 2 files changed, 57 insertions(+), 71 deletions(-)
---
diff --git a/src/composer/e-msg-composer.c b/src/composer/e-msg-composer.c
index 4833496..7170e2a 100644
--- a/src/composer/e-msg-composer.c
+++ b/src/composer/e-msg-composer.c
@@ -1716,14 +1716,9 @@ msg_composer_paste_clipboard_targets_cb (GtkClipboard *clipboard,
        editor = e_msg_composer_get_editor (composer);
        cnt_editor = e_html_editor_get_content_editor (editor);
 
-       /* Order is important here to ensure common use cases are
-        * handled correctly.  See GNOME bug #603715 for details. */
-       if (gtk_targets_include_text (targets, n_targets) ||
-           e_targets_include_html (targets, n_targets)) {
-               if (composer->priv->last_signal_was_paste_primary) {
-                       e_content_editor_paste_primary (cnt_editor);
-               } else
-                       e_content_editor_paste (cnt_editor);
+       if (!e_content_editor_get_html_mode (cnt_editor) &&
+           gtk_targets_include_image (targets, n_targets, TRUE)) {
+               e_composer_paste_image (composer, clipboard);
                return;
        }
 
@@ -1732,9 +1727,14 @@ msg_composer_paste_clipboard_targets_cb (GtkClipboard *clipboard,
                return;
        }
 
-       if (!e_content_editor_get_html_mode (cnt_editor) &&
-           gtk_targets_include_image (targets, n_targets, TRUE)) {
-               e_composer_paste_image (composer, clipboard);
+       /* Order is important here to ensure common use cases are
+        * handled correctly.  See GNOME bug #603715 for details. */
+       if (gtk_targets_include_text (targets, n_targets) ||
+           e_targets_include_html (targets, n_targets)) {
+               if (composer->priv->last_signal_was_paste_primary) {
+                       e_content_editor_paste_primary (cnt_editor);
+               } else
+                       e_content_editor_paste (cnt_editor);
                return;
        }
 
diff --git a/src/modules/webkit-editor/e-webkit-editor.c b/src/modules/webkit-editor/e-webkit-editor.c
index fa7faeb..03b4047 100644
--- a/src/modules/webkit-editor/e-webkit-editor.c
+++ b/src/modules/webkit-editor/e-webkit-editor.c
@@ -5604,6 +5604,9 @@ webkit_editor_paste_clipboard_targets_cb (GtkClipboard *clipboard,
                                           gint n_targets,
                                           EWebKitEditor *wk_editor)
 {
+       gchar *content = NULL;
+       gboolean is_html = FALSE;
+
        if (targets == NULL || n_targets < 0)
                return;
 
@@ -5611,76 +5614,36 @@ webkit_editor_paste_clipboard_targets_cb (GtkClipboard *clipboard,
        if (!gtk_widget_has_focus (GTK_WIDGET (wk_editor)))
                gtk_widget_grab_focus (GTK_WIDGET (wk_editor));
 
-       /* Order is important here to ensure common use cases are
-        * handled correctly.  See GNOME bug #603715 for details. */
-       /* Prefer plain text over HTML when in the plain text mode, but only
-        * when pasting content from outside the editor view. */
+       /* Save the text content before we try to insert the image as it could
+        * happen that we fail to save the image from clipboard (not by our
+        * fault - right now it looks like current web engines can't handle IMG
+        * with SRCSET attribute in clipboard correctly). And if this fails the
+        * source application can cancel the content and we could not fallback
+        * to at least some content. */
        if (wk_editor->priv->html_mode ||
            webkit_editor_paste_prefer_text_html (wk_editor)) {
-               gchar *content = NULL;
-
                if (e_targets_include_html (targets, n_targets)) {
-                       if (!(content = e_clipboard_wait_for_html (clipboard)))
-                               return;
-
-                       webkit_editor_insert_content (
-                               E_CONTENT_EDITOR (wk_editor),
-                               content,
-                               E_CONTENT_EDITOR_INSERT_TEXT_HTML);
-
-                       g_free (content);
-                       return;
-               }
-
-               if (gtk_targets_include_text (targets, n_targets)) {
-                       if (!(content = gtk_clipboard_wait_for_text (clipboard)))
-                               return;
-
-                       webkit_editor_insert_content (
-                               E_CONTENT_EDITOR (wk_editor),
-                               content,
-                               E_CONTENT_EDITOR_INSERT_TEXT_PLAIN |
-                               E_CONTENT_EDITOR_INSERT_CONVERT);
-
-                       g_free (content);
-                       return;
-               }
+                       content = e_clipboard_wait_for_html (clipboard);
+                       is_html = TRUE;
+               } else if (gtk_targets_include_text (targets, n_targets))
+                       content = gtk_clipboard_wait_for_text (clipboard)
        } else {
-               gchar *content = NULL;
-
-               if (gtk_targets_include_text (targets, n_targets)) {
-                       if (!(content = gtk_clipboard_wait_for_text (clipboard)))
-                               return;
-
-                       webkit_editor_insert_content (
-                               E_CONTENT_EDITOR (wk_editor),
-                               content,
-                               E_CONTENT_EDITOR_INSERT_TEXT_PLAIN |
-                               E_CONTENT_EDITOR_INSERT_CONVERT);
-
-                       g_free (content);
-                       return;
-               }
-
-               if (e_targets_include_html (targets, n_targets)) {
-                       if (!(content = e_clipboard_wait_for_html (clipboard)))
-                               return;
-
-                       webkit_editor_insert_content (
-                               E_CONTENT_EDITOR (wk_editor),
-                               content,
-                               E_CONTENT_EDITOR_INSERT_TEXT_HTML);
-
-                       g_free (content);
-                       return;
+               if (gtk_targets_include_text (targets, n_targets))
+                       content = gtk_clipboard_wait_for_text (clipboard);
+               else if (e_targets_include_html (targets, n_targets)) {
+                       content = e_clipboard_wait_for_html (clipboard);
+                       is_html = TRUE;
                }
        }
 
-       if (gtk_targets_include_image (targets, n_targets, TRUE)) {
+       if (wk_editor->priv->html_mode &&
+           gtk_targets_include_image (targets, n_targets, TRUE)) {
                gchar *uri;
 
                if (!(uri = e_util_save_image_from_clipboard (clipboard)))
-                       return;
+                       goto fallback;
+
+               webkit_editor_set_changed (wk_editor, TRUE);
 
                webkit_editor_insert_image (E_CONTENT_EDITOR (wk_editor), uri);
 
@@ -5688,6 +5651,29 @@ webkit_editor_paste_clipboard_targets_cb (GtkClipboard *clipboard,
 
                return;
        }
+
+ fallback:
+       /* Order is important here to ensure common use cases are
+        * handled correctly.  See GNOME bug #603715 for details. */
+       /* Prefer plain text over HTML when in the plain text mode, but only
+        * when pasting content from outside the editor view. */
+
+       if (!content && !*content)
+               return;
+
+       if (is_html)
+               webkit_editor_insert_content (
+                       E_CONTENT_EDITOR (wk_editor),
+                       content,
+                       E_CONTENT_EDITOR_INSERT_TEXT_HTML);
+       else
+               webkit_editor_insert_content (
+                       E_CONTENT_EDITOR (wk_editor),
+                       content,
+                       E_CONTENT_EDITOR_INSERT_TEXT_PLAIN |
+                       E_CONTENT_EDITOR_INSERT_CONVERT);
+
+       g_free (content);
 }
 
 static void