[gnome-builder/wip/chergert/layout] spellcheck: add utility helpers

[Christian Hergert <chergert src gnome org>]

commit bfd8d583be6733db3cc9b104dfdda27be3e331c2
Author: Christian Hergert <chergert redhat com>
Date:   Sat Jul 15 19:48:28 2017 -0700

    spellcheck: add utility helpers
    
    This adds back the utility helpers under their new namespace

 plugins/spellcheck/gbp-spell-utils.c |  198 ++++++++++++++++++++++++++++++++++
 plugins/spellcheck/gbp-spell-utils.h |   35 ++++++
 plugins/spellcheck/meson.build       |    2 +
 3 files changed, 235 insertions(+), 0 deletions(-)
---
diff --git a/plugins/spellcheck/gbp-spell-utils.c b/plugins/spellcheck/gbp-spell-utils.c
new file mode 100644
index 0000000..d3af474
--- /dev/null
+++ b/plugins/spellcheck/gbp-spell-utils.c
@@ -0,0 +1,198 @@
+/* gbp-spell-utils.c
+ *
+ * Copyright (C) 2016 Sebastien Lafargue <slafargue gnome org>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ * This code is mostly from:
+ * https://git.gnome.org/browse/gspell/tree/gspell/gspell-utils.c
+ * https://git.gnome.org/browse/gspell/tree/gspell/gspell-text-iter.c
+ */
+
+#define G_LOG_DOMAIN "gbp-spell-utils"
+
+#include <gtk/gtk.h>
+
+#include "gbp-spell-utils.h"
+
+/* gunichar decimal value of unicode apostrophe characters. */
+#define GSPELL_MODIFIER_LETTER_APOSTROPHE (700) /* U+02BC */
+#define GSPELL_RIGHT_SINGLE_QUOTATION_MARK (8217) /* U+2019 */
+
+static inline gboolean
+is__text_iter_apostrophe_or_dash (const GtkTextIter *iter)
+{
+  gunichar ch;
+
+  ch = gtk_text_iter_get_char (iter);
+
+  return (ch == '-' ||
+          ch == '\'' ||
+          ch == GSPELL_MODIFIER_LETTER_APOSTROPHE ||
+          ch == GSPELL_RIGHT_SINGLE_QUOTATION_MARK);
+}
+
+gboolean
+gbp_spell_utils_text_iter_forward_word_end (GtkTextIter *iter)
+{
+  g_return_val_if_fail (iter != NULL, FALSE);
+
+  while (gtk_text_iter_forward_word_end (iter))
+    {
+      GtkTextIter next_char;
+
+      if (!is__text_iter_apostrophe_or_dash (iter))
+        return TRUE;
+
+      next_char = *iter;
+      gtk_text_iter_forward_char (&next_char);
+      if (!gtk_text_iter_starts_word (&next_char))
+        return TRUE;
+
+      *iter = next_char;
+    }
+
+  return FALSE;
+}
+
+gboolean
+gbp_spell_utils_text_iter_backward_word_start (GtkTextIter *iter)
+{
+  g_return_val_if_fail (iter != NULL, FALSE);
+
+  while (gtk_text_iter_backward_word_start (iter))
+    {
+      GtkTextIter prev_char = *iter;
+
+      if (!gtk_text_iter_backward_char (&prev_char) ||
+          !is__text_iter_apostrophe_or_dash (&prev_char) ||
+          !gtk_text_iter_ends_word (&prev_char))
+        return TRUE;
+
+      *iter = prev_char;
+    }
+
+  return FALSE;
+}
+
+gboolean
+gbp_spell_utils_text_iter_starts_word (const GtkTextIter *iter)
+{
+  GtkTextIter prev_char;
+
+  g_return_val_if_fail (iter != NULL, FALSE);
+
+  if (!gtk_text_iter_starts_word (iter))
+    return FALSE;
+
+  prev_char = *iter;
+  if (!gtk_text_iter_backward_char (&prev_char))
+    return TRUE;
+
+  if (is__text_iter_apostrophe_or_dash (&prev_char) &&
+      gtk_text_iter_ends_word (&prev_char))
+    return FALSE;
+
+  return TRUE;
+}
+
+gboolean
+gbp_spell_utils_text_iter_ends_word (const GtkTextIter *iter)
+{
+  GtkTextIter next_char;
+
+  g_return_val_if_fail (iter != NULL, FALSE);
+
+  if (!gtk_text_iter_ends_word (iter))
+    return FALSE;
+
+  if (gtk_text_iter_is_end (iter))
+    return TRUE;
+
+  next_char = *iter;
+  gtk_text_iter_forward_char (&next_char);
+
+  if (is__text_iter_apostrophe_or_dash (iter) &&
+      gtk_text_iter_starts_word (&next_char))
+    return FALSE;
+
+  return TRUE;
+}
+
+gboolean
+gbp_spell_utils_text_iter_inside_word (const GtkTextIter *iter)
+{
+  g_return_val_if_fail (iter != NULL, FALSE);
+
+  if (gtk_text_iter_inside_word (iter))
+    return TRUE;
+
+  if (gtk_text_iter_ends_word (iter) &&
+      is__text_iter_apostrophe_or_dash (iter))
+    {
+      GtkTextIter next_char = *iter;
+      gtk_text_iter_forward_char (&next_char);
+      return gtk_text_iter_starts_word (&next_char);
+    }
+
+  return FALSE;
+}
+
+GtkTextTag *
+gbp_spell_utils_get_no_spell_check_tag (GtkTextBuffer *buffer)
+{
+  GtkTextTagTable *tag_table;
+
+  g_return_val_if_fail (GTK_IS_TEXT_BUFFER (buffer), NULL);
+
+  tag_table = gtk_text_buffer_get_tag_table (buffer);
+
+  return gtk_text_tag_table_lookup (tag_table, "gtksourceview:context-classes:no-spell-check");
+}
+
+gboolean
+gbp_spell_utils_skip_no_spell_check (GtkTextTag        *no_spell_check_tag,
+                                     GtkTextIter       *start,
+                                     const GtkTextIter *end)
+{
+  g_return_val_if_fail (start != NULL, FALSE);
+  g_return_val_if_fail (end != NULL, FALSE);
+
+  if (no_spell_check_tag == NULL)
+    return TRUE;
+
+  g_return_val_if_fail (GTK_IS_TEXT_TAG (no_spell_check_tag), FALSE);
+
+  while (gtk_text_iter_has_tag (start, no_spell_check_tag))
+    {
+      GtkTextIter last = *start;
+
+      if (!gtk_text_iter_forward_to_tag_toggle (start, no_spell_check_tag))
+        return FALSE;
+
+      if (gtk_text_iter_compare (start, &last) <= 0)
+        return FALSE;
+
+      gbp_spell_utils_text_iter_forward_word_end (start);
+      gbp_spell_utils_text_iter_backward_word_start (start);
+
+      if (gtk_text_iter_compare (start, &last) <= 0)
+        return FALSE;
+
+      if (gtk_text_iter_compare (start, end) >= 0)
+        return FALSE;
+  }
+
+  return TRUE;
+}
diff --git a/plugins/spellcheck/gbp-spell-utils.h b/plugins/spellcheck/gbp-spell-utils.h
new file mode 100644
index 0000000..31e419b
--- /dev/null
+++ b/plugins/spellcheck/gbp-spell-utils.h
@@ -0,0 +1,35 @@
+/* gbp-spell-utils.h
+ *
+ * Copyright (C) 2016 Sebastien Lafargue <slafargue gnome org>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#pragma once
+
+#include <gtk/gtk.h>
+
+G_BEGIN_DECLS
+
+gboolean    gbp_spell_utils_text_iter_forward_word_end    (GtkTextIter        *iter);
+gboolean    gbp_spell_utils_text_iter_backward_word_start (GtkTextIter        *iter);
+gboolean    gbp_spell_utils_text_iter_starts_word         (const GtkTextIter  *iter);
+gboolean    gbp_spell_utils_text_iter_ends_word           (const GtkTextIter  *iter);
+gboolean    gbp_spell_utils_text_iter_inside_word         (const GtkTextIter  *iter);
+GtkTextTag *gbp_spell_utils_get_no_spell_check_tag        (GtkTextBuffer      *buffer);
+gboolean    gbp_spell_utils_skip_no_spell_check           (GtkTextTag         *no_spell_check_tag,
+                                                           GtkTextIter        *start,
+                                                           const GtkTextIter  *end);
+
+G_END_DECLS
diff --git a/plugins/spellcheck/meson.build b/plugins/spellcheck/meson.build
index 91fcb0a..40bf75f 100644
--- a/plugins/spellcheck/meson.build
+++ b/plugins/spellcheck/meson.build
@@ -16,6 +16,8 @@ spellcheck_sources = [
   'gbp-spell-editor-addin.h',
   'gbp-spell-editor-view-addin.c',
   'gbp-spell-editor-view-addin.h',
+  'gbp-spell-utils.c',
+  'gbp-spell-utils.h',
   spellcheck_resources[0],
 ]