Work around pango bug

See https://gitlab.gnome.org/GNOME/pango/-/issues/798 and https://gitlab.gnome.org/GNOME/pango/-/issues/832

6 files changed, 51 insertions, 4 deletions

diff --git a/main/src/ui/call_window/call_bottom_bar.vala b/main/src/ui/call_window/call_bottom_bar.vala
index 641a4def..e0848cc9 100644
--- a/main/src/ui/call_window/call_bottom_bar.vala
+++ b/main/src/ui/call_window/call_bottom_bar.vala
@@ -138,7 +138,7 @@ public class Dino.Ui.CallBottomBar : Gtk.Box {
 
     public void show_counterpart_ended(string text) {
         stack.set_visible_child_name("label");
-        label.label = text;
+        label.label = Util.unbreak_space_around_non_spacing_mark(text);
     }
 
     public bool is_menu_active() {
diff --git a/main/src/ui/conversation_content_view/message_widget.vala b/main/src/ui/conversation_content_view/message_widget.vala
index 376ef4bd..d116e7de 100644
--- a/main/src/ui/conversation_content_view/message_widget.vala
+++ b/main/src/ui/conversation_content_view/message_widget.vala
@@ -140,6 +140,9 @@ public class MessageMetaItem : ContentMetaItem {
             }
         }
 
+        // Work around pango bug
+        markup_text = Util.unbreak_space_around_non_spacing_mark((owned) markup_text);
+
         if (conversation.type_ == Conversation.Type.GROUPCHAT) {
             markup_text = Util.parse_add_markup_theme(markup_text, conversation.nickname, true, true, true, Util.is_dark_theme(this.label), ref theme_dependent);
         } else {
diff --git a/main/src/ui/global_search.vala b/main/src/ui/global_search.vala
index 2fb31a90..a63aaed1 100644
--- a/main/src/ui/global_search.vala
+++ b/main/src/ui/global_search.vala
@@ -223,7 +223,7 @@ public class GlobalSearch {
         grid.margin_top = 3;
         grid.margin_bottom = 3;
 
-        string text = item.message.body.replace("\n", "").replace("\r", "");
+        string text = Util.unbreak_space_around_non_spacing_mark(item.message.body.replace("\n", "").replace("\r", ""));
         if (text.length > 200) {
             int index = text.index_of(search);
             if (index + search.length <= 100) {
diff --git a/main/src/ui/util/helper.vala b/main/src/ui/util/helper.vala
index e12dfe20..578e313a 100644
--- a/main/src/ui/util/helper.vala
+++ b/main/src/ui/util/helper.vala
@@ -170,6 +170,41 @@ public static Map<unichar, unichar> get_matching_chars() {
     return MATCHING_CHARS;
 }
 
+/**
+ * This replaces spaces with non-breaking spaces when they are adjacent to a non-spacing mark.
+ *
+ * We do this to work-around a bug in Pango. See https://gitlab.gnome.org/GNOME/pango/-/issues/798 and
+ * https://gitlab.gnome.org/GNOME/pango/-/issues/832
+ *
+ * This is zero-copy iff no space is adjacent to a non-spacing mark, otherwise the provided string will be destroyed
+ * and the returned string should be used instead.
+ */
+public static string unbreak_space_around_non_spacing_mark(owned string s) {
+    int current_index = 0;
+    unichar current_char = 0;
+    int prev_index = 0;
+    unichar prev_char = 0;
+    bool is_non_spacing_mark = false;
+    while (s.get_next_char(ref current_index, out current_char)) {
+        int replace_index = -1;
+        if (is_non_spacing_mark && current_char == ' ') {
+            replace_index = prev_index;
+            current_char = ' ';
+        }
+        is_non_spacing_mark = ICU.get_int_property_value(current_char, ICU.Property.BIDI_CLASS) == ICU.CharDirection.DIR_NON_SPACING_MARK;
+        if (prev_char == ' ' && is_non_spacing_mark) {
+            replace_index = prev_index - 1;
+        }
+        if (replace_index != -1) {
+            s = s[0:replace_index] + " " + s[(replace_index + 1):s.length];
+            current_index += 1;
+        }
+        prev_index = current_index;
+        prev_char = current_char;
+    }
+    return (owned) s;
+}
+
 public static string parse_add_markup(string s_, string? highlight_word, bool parse_links, bool parse_text_markup) {
     bool ignore_out_var = false;
     return parse_add_markup_theme(s_, highlight_word, parse_links, parse_text_markup, parse_text_markup, false, ref ignore_out_var);
diff --git a/main/src/windows/preferences_window/add_account_dialog.vala b/main/src/windows/preferences_window/add_account_dialog.vala
index bfa98103..3ca183e1 100644
--- a/main/src/windows/preferences_window/add_account_dialog.vala
+++ b/main/src/windows/preferences_window/add_account_dialog.vala
@@ -311,7 +311,7 @@ public class AddAccountDialog : Adw.Window {
             register_form_continue.grab_focus();
         } else if (form.fields.size > 0) {
             if (form.instructions != null && form.instructions != "") {
-                string markup_instructions = Util.parse_add_markup(form.instructions, null, true, false);
+                string markup_instructions = Util.parse_add_markup(Util.unbreak_space_around_non_spacing_mark(form.instructions), null, true, false);
                 form_box.append(new Label(markup_instructions) { use_markup=true, xalign=0, margin_top=7,
                     wrap=true, wrap_mode=Pango.WrapMode.WORD_CHAR });
             }
diff --git a/main/vapi/icu-uc.vapi b/main/vapi/icu-uc.vapi
index db1609ad..9eb3d274 100644
--- a/main/vapi/icu-uc.vapi
+++ b/main/vapi/icu-uc.vapi
@@ -1,14 +1,23 @@
 namespace ICU {
 
-[CCode (cprefix = "UCHAR_", cheader_filename = "unicode/uchar.h")]
+[CCode (cname = "UProperty", cprefix = "UCHAR_", has_type_id = false, cheader_filename = "unicode/uchar.h")]
 public enum Property {
     EMOJI,
     EMOJI_PRESENTATION,
     EMOJI_MODIFIER,
     EMOJI_MODIFIER_BASE,
+    BIDI_CLASS,
+}
+
+[CCode (cname = "UCharDirection", cprefix = "U_", has_type_id = false, cheader_filename = "unicode/uchar.h")]
+public enum CharDirection {
+    DIR_NON_SPACING_MARK,
 }
 
 [CCode (cname = "u_hasBinaryProperty", cheader_filename = "unicode/uchar.h")]
 public bool has_binary_property(unichar c, Property p);
 
+[CCode (cname = "u_getIntPropertyValue", cheader_filename = "unicode/uchar.h")]
+public int32 get_int_property_value(unichar c, Property p);
+
 }