[gnumeric] Clipboard: don't offer or accept formats we cannot handle

[Morten Welinder <mortenw src gnome org>]

commit 1b92e43ef6fda94204e7b98079e7ec234aebca5d
Author: Morten Welinder <terra gnome org>
Date:   Sat Apr 21 16:02:10 2018 -0400

    Clipboard: don't offer or accept formats we cannot handle
    
    This could happen if some plugin was missing.

 src/gui-clipboard.c |   87 ++++++++++++++++++++++++++++++++++-----------------
 1 files changed, 58 insertions(+), 29 deletions(-)
---
diff --git a/src/gui-clipboard.c b/src/gui-clipboard.c
index f0d235d..fbd2aa2 100644
--- a/src/gui-clipboard.c
+++ b/src/gui-clipboard.c
@@ -49,6 +49,12 @@
 
 #define APP_CLIP_DISP_KEY "clipboard-displays"
 
+#define EXCEL_FILE_OPENER "Gnumeric_Excel:excel"
+#define EXCEL_FILE_SAVER "Gnumeric_Excel:excel_biff8"
+#define HTML_FILE_OPENER "Gnumeric_html:html"
+#define HTML_FILE_SAVER "Gnumeric_html:xhtml_range"
+#define OOO_FILE_OPENER "Gnumeric_OpenCalc:openoffice"
+
 // ----------------------------------------------------------------------------
 
 static gboolean debug_clipboard;
@@ -152,6 +158,20 @@ gnm_gtk_clipboard_context_free (GnmGtkClipboardCtxt *ctxt)
  * (x-get-selection-internal 'CLIPBOARD 'TARGETS)
  */
 
+static gboolean
+has_file_opener (const char *id)
+{
+       return go_file_opener_for_id (id) != NULL;
+}
+
+static gboolean
+has_file_saver (const char *id)
+{
+       return go_file_saver_for_id (id) != NULL;
+}
+
+
+
 static void
 paste_from_gnumeric (GtkSelectionData *selection_data, GdkAtom target,
                     gconstpointer data, gssize size)
@@ -583,7 +603,7 @@ table_content_received (GtkClipboard *clipboard, GtkSelectionData *sel,
        } else if (target == atoms[ATOM_OOO] ||
                   target == atoms[ATOM_OOO_WINDOWS] ||
                   target == atoms[ATOM_OOO11]) {
-               content = table_cellregion_read (wbc, "Gnumeric_OpenCalc:openoffice",
+               content = table_cellregion_read (wbc, OOO_FILE_OPENER,
                                                 pt, buffer,
                                                 sel_len);
        } else if (target == atoms[ATOM_TEXT_HTML] ||
@@ -595,7 +615,7 @@ table_content_received (GtkClipboard *clipboard, GtkSelectionData *sel,
                        parse_ms_headers (buffer, sel_len, &start, &end);
                }
 
-               content = table_cellregion_read (wbc, "Gnumeric_html:html",
+               content = table_cellregion_read (wbc, HTML_FILE_OPENER,
                                                 pt,
                                                 buffer + start,
                                                 end - start);
@@ -604,7 +624,7 @@ table_content_received (GtkClipboard *clipboard, GtkSelectionData *sel,
                   target == atoms[ATOM_BIFF8_OO] ||
                   target == atoms[ATOM_BIFF5] ||
                   target == atoms[ATOM_BIFF]) {
-               content = table_cellregion_read (wbc, "Gnumeric_Excel:excel",
+               content = table_cellregion_read (wbc, EXCEL_FILE_OPENER,
                                                 pt, buffer,
                                                 sel_len);
        }
@@ -653,12 +673,20 @@ x_targets_received (GtkClipboard *clipboard, GdkAtom *targets,
        unsigned ui;
 
        // In order of preference
-       static const int table_fmts[] = {
-               ATOM_GNUMERIC,
-               ATOM_BIFF8, ATOM_BIFF8_CITRIX,
-               ATOM_OOO, ATOM_OOO11, ATOM_OOO_WINDOWS,
-               ATOM_BIFF5, ATOM_BIFF,
-               ATOM_TEXT_HTML, ATOM_TEXT_HTML_WINDOWS,
+       static const struct {
+               int a;
+               const char *opener_id;
+       } table_fmts[] = {
+               { ATOM_GNUMERIC, NULL },
+               { ATOM_BIFF8, EXCEL_FILE_OPENER },
+               { ATOM_BIFF8_CITRIX, EXCEL_FILE_OPENER },
+               { ATOM_OOO, OOO_FILE_OPENER },
+               { ATOM_OOO11, OOO_FILE_OPENER },
+               { ATOM_OOO_WINDOWS, OOO_FILE_OPENER },
+               { ATOM_BIFF5, EXCEL_FILE_OPENER },
+               { ATOM_BIFF, EXCEL_FILE_OPENER },
+               { ATOM_TEXT_HTML, HTML_FILE_OPENER },
+               { ATOM_TEXT_HTML_WINDOWS, HTML_FILE_OPENER },
        };
 
        // In order of preference
@@ -688,8 +716,10 @@ x_targets_received (GtkClipboard *clipboard, GdkAtom *targets,
 
        // First look for anything that can be considered a spreadsheet
        for (ui = 0; ui < G_N_ELEMENTS(table_fmts); ui++) {
-               GdkAtom atom = atoms[table_fmts[ui]];
-               if (find_in_table (targets, n_targets, atom)) {
+               GdkAtom atom = atoms[table_fmts[ui].a];
+               const char *opener = table_fmts[ui].opener_id;
+               if ((opener == NULL || has_file_opener (opener)) &&
+                   find_in_table (targets, n_targets, atom)) {
                        gtk_clipboard_request_contents (clipboard, atom,
                                                        table_content_received,
                                                        ctxt);
@@ -821,8 +851,6 @@ image_write (GnmCellRegion *cr, gchar const *mime_type, int *size)
        so = GNM_SO (cr->objects->data);
        g_return_val_if_fail (so != NULL, NULL);
 
-       if (strncmp (mime_type, "image/", 6) != 0)
-               return ret;
        for (l = cr->objects; l != NULL; l = l->next) {
                if (GNM_IS_SO_IMAGEABLE (GNM_SO (l->data))) {
                        so = GNM_SO (l->data);
@@ -830,12 +858,14 @@ image_write (GnmCellRegion *cr, gchar const *mime_type, int *size)
                }
        }
        if (so == NULL) {
-               g_warning ("non imageable object requested as image\n");
+               // This shouldn't happen
+               g_warning ("non-imageable object requested as image\n");
                return ret;
        }
 
        format = go_mime_to_image_format (mime_type);
        if (!format) {
+               // This shouldn't happen
                g_warning ("No image format for %s\n", mime_type);
                return ret;
        }
@@ -956,18 +986,16 @@ x_clipboard_get_cb (GtkClipboard *gclipboard, GtkSelectionData *selection_data,
                        to_gnumeric = TRUE;
                }
        } else if (info == INFO_HTML) {
-               const char *saver_id = "Gnumeric_html:xhtml_range";
                int size;
                guchar *buffer = table_cellregion_write (ctx, clipboard,
-                                                        saver_id,
+                                                        HTML_FILE_SAVER,
                                                         &size);
                paste_from_gnumeric (selection_data, target, buffer, size);
                g_free (buffer);
        } else if (info == INFO_EXCEL) {
-               const char *saver_id = "Gnumeric_Excel:excel_biff8";
                int size;
                guchar *buffer = table_cellregion_write (ctx, clipboard,
-                                                        saver_id,
+                                                        EXCEL_FILE_SAVER,
                                                         &size);
                paste_from_gnumeric (selection_data, target, buffer, size);
                g_free (buffer);
@@ -983,9 +1011,8 @@ x_clipboard_get_cb (GtkClipboard *gclipboard, GtkSelectionData *selection_data,
                paste_from_gnumeric (selection_data, target, buffer, size);
                g_free (buffer);
        } else if (target == atoms[ATOM_SAVE_TARGETS]) {
-               /* We implicitly registered this when calling
-                * gtk_clipboard_set_can_store. We're supposed to
-                * ignore it. */
+               // We implicitly registered this target when calling
+               // gtk_clipboard_set_can_store. We're supposed to ignore it.
        } else if (info == INFO_GENERIC_TEXT) {
                Workbook *wb = clipboard->origin_sheet->workbook;
                GString *res = cellregion_to_string (clipboard,
@@ -1011,7 +1038,6 @@ x_clipboard_get_cb (GtkClipboard *gclipboard, GtkSelectionData *selection_data,
         * the clipboard
         */
        if (content_needs_free) {
-
                /* If the other app was a gnumeric, emulate a cut */
                if (to_gnumeric) {
                        GOUndo *redo, *undo;
@@ -1069,8 +1095,7 @@ gnm_x_request_clipboard (WBCGtk *wbcg, GnmPasteTarget const *pt)
 
        ctxt = g_new (GnmGtkClipboardCtxt, 1);
        ctxt->wbcg = wbcg;
-       ctxt->paste_target = g_new (GnmPasteTarget, 1);
-       *ctxt->paste_target = *pt;
+       ctxt->paste_target = g_memdup (pt, sizeof (*pt));
 
        /* Query the formats, This will callback x_targets_received */
        gtk_clipboard_request_targets (clipboard,
@@ -1174,14 +1199,18 @@ gnm_x_claim_clipboard (GdkDisplay *display)
                }
        } else {
                add_target (targets, atom_names[ATOM_GNUMERIC], 0, INFO_GNUMERIC);
-               add_target (targets, atom_names[ATOM_BIFF8], 0, INFO_EXCEL);
-               add_target (targets, atom_names[ATOM_BIFF8_CITRIX], 0, INFO_EXCEL);
-               add_target (targets, atom_names[ATOM_BIFF8_OO], 0, INFO_EXCEL);
+               if (has_file_saver (EXCEL_FILE_SAVER)) {
+                       add_target (targets, atom_names[ATOM_BIFF8], 0, INFO_EXCEL);
+                       add_target (targets, atom_names[ATOM_BIFF8_CITRIX], 0, INFO_EXCEL);
+                       add_target (targets, atom_names[ATOM_BIFF8_OO], 0, INFO_EXCEL);
+               }
+               if (has_file_saver (HTML_FILE_SAVER)) {
 #ifdef G_OS_WIN32
-               add_target (targets, atom_names[ATOM_TEXT_HTML_WINDOWS], 0, INFO_HTML);
+                       add_target (targets, atom_names[ATOM_TEXT_HTML_WINDOWS], 0, INFO_HTML);
 #else
-               add_target (targets, atom_names[ATOM_TEXT_HTML], 0, INFO_HTML);
+                       add_target (targets, atom_names[ATOM_TEXT_HTML], 0, INFO_HTML);
 #endif
+               }
                add_target (targets, atom_names[ATOM_UTF8_STRING], 0, INFO_GENERIC_TEXT);
                add_target (targets, atom_names[ATOM_COMPOUND_TEXT], 0, INFO_GENERIC_TEXT);
                add_target (targets, atom_names[ATOM_STRING], 0, INFO_GENERIC_TEXT);