[gnome-builder/wip/libide] libide: add GtkTextIter helpers that conform to vim conventions

[Christian Hergert <chergert src gnome org>]

commit df79745aed1d257869c57866a98fa306994798c4
Author: Christian Hergert <christian hergert me>
Date:   Wed Mar 4 20:17:56 2015 -0800

    libide: add GtkTextIter helpers that conform to vim conventions
    
    Sentences and paragraphs have specific vim meanings, so lets keep these
    seperate.

 libide/Makefile.am    |    2 +
 libide/ide-vim-iter.c |  208 +++++++++++++++++++++++++++++++++++++++++++++++++
 libide/ide-vim-iter.h |   33 ++++++++
 3 files changed, 243 insertions(+), 0 deletions(-)
---
diff --git a/libide/Makefile.am b/libide/Makefile.am
index aa4b3a5..1b9397a 100644
--- a/libide/Makefile.am
+++ b/libide/Makefile.am
@@ -223,6 +223,8 @@ libide_1_0_la_SOURCES = \
        libide/ide-source-snippet-private.h \
        libide/ide-source-view-movements.c \
        libide/ide-source-view-movements.h \
+       libide/ide-vim-iter.c \
+       libide/ide-vim-iter.h \
        libide/tasks/ide-load-directory-task.c \
        libide/tasks/ide-load-directory-task.h \
        libide/theatrics/ide-animation.c \
diff --git a/libide/ide-vim-iter.c b/libide/ide-vim-iter.c
new file mode 100644
index 0000000..81f55af
--- /dev/null
+++ b/libide/ide-vim-iter.c
@@ -0,0 +1,208 @@
+/* ide-vim-iter.c
+ *
+ * Copyright (C) 2015 Christian Hergert <christian hergert me>
+ *
+ * This file is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This file 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
+ * Lesser 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/>.
+ */
+
+#include <gtk/gtk.h>
+
+#include "ide-debug.h"
+#include "ide-vim-iter.h"
+
+typedef enum
+{
+  SENTENCE_OK,
+  SENTENCE_PARA,
+  SENTENCE_FAILED,
+} SentenceStatus;
+
+static gboolean
+_ide_vim_iter_line_is_empty (GtkTextIter *iter)
+{
+  return gtk_text_iter_starts_line (iter) && gtk_text_iter_ends_line (iter);
+}
+
+/**
+ * _ide_vim_iter_backward_paragraph_start:
+ * @iter: A #GtkTextIter
+ *
+ * Searches backwards until we find the beginning of a paragraph.
+ *
+ * Returns: %TRUE if we are not at the beginning of the buffer; otherwise %FALSE.
+ */
+gboolean
+_ide_vim_iter_backward_paragraph_start (GtkTextIter *iter)
+{
+  g_return_val_if_fail (iter, FALSE);
+
+  /* Work our way past the current empty lines */
+  if (_ide_vim_iter_line_is_empty (iter))
+    while (_ide_vim_iter_line_is_empty (iter))
+      if (!gtk_text_iter_backward_line (iter))
+        return FALSE;
+
+  /* Now find first line that is empty */
+  while (!_ide_vim_iter_line_is_empty (iter))
+    if (!gtk_text_iter_backward_line (iter))
+      return FALSE;
+
+  return TRUE;
+}
+
+/**
+ * _ide_vim_iter_forward_paragraph_end:
+ * @iter: A #GtkTextIter
+ *
+ * Searches forward until the end of a paragraph has been hit.
+ *
+ * Returns: %TRUE if we are not at the end of the buffer; otherwise %FALSE.
+ */
+gboolean
+_ide_vim_iter_forward_paragraph_end (GtkTextIter *iter)
+{
+  g_return_val_if_fail (iter, FALSE);
+
+  /* Work our way past the current empty lines */
+  if (_ide_vim_iter_line_is_empty (iter))
+    while (_ide_vim_iter_line_is_empty (iter))
+      if (!gtk_text_iter_forward_line (iter))
+        return FALSE;
+
+  /* Now find first line that is empty */
+  while (!_ide_vim_iter_line_is_empty (iter))
+    if (!gtk_text_iter_forward_line (iter))
+      return FALSE;
+
+  return TRUE;
+}
+
+static gboolean
+sentence_end_chars (gunichar ch,
+                    gpointer user_data)
+{
+  switch (ch)
+    {
+    case '!':
+    case '.':
+    case '?':
+      return TRUE;
+
+    default:
+      return FALSE;
+    }
+}
+
+static SentenceStatus
+_ide_vim_iter_backward_sentence_end (GtkTextIter *iter)
+{
+  GtkTextIter end_bounds;
+  GtkTextIter start_bounds;
+  gboolean found_para;
+
+  g_return_val_if_fail (iter, FALSE);
+
+  end_bounds = *iter;
+  start_bounds = *iter;
+  found_para = _ide_vim_iter_backward_paragraph_start (&start_bounds);
+
+  if (!found_para)
+    gtk_text_buffer_get_start_iter (gtk_text_iter_get_buffer (iter), &start_bounds);
+
+  while ((gtk_text_iter_compare (iter, &start_bounds) > 0) && gtk_text_iter_backward_char (iter))
+    {
+      if (gtk_text_iter_backward_find_char (iter, sentence_end_chars, NULL, &end_bounds))
+        {
+          GtkTextIter copy = *iter;
+
+          while (gtk_text_iter_forward_char (&copy) && (gtk_text_iter_compare (&copy, &end_bounds) < 0))
+            {
+              gunichar ch;
+
+              ch = gtk_text_iter_get_char (&copy);
+
+              switch (ch)
+                {
+                case ']':
+                case ')':
+                case '"':
+                case '\'':
+                  continue;
+
+                case ' ':
+                case '\n':
+                  *iter = copy;
+                  return SENTENCE_OK;
+
+                default:
+                  break;
+                }
+            }
+        }
+    }
+
+  *iter = start_bounds;
+
+  if (found_para)
+    return SENTENCE_PARA;
+
+  return SENTENCE_FAILED;
+}
+
+gboolean
+_ide_vim_iter_forward_sentence_end (GtkTextIter *iter)
+{
+  g_return_val_if_fail (iter, FALSE);
+
+  return FALSE;
+}
+
+gboolean
+_ide_vim_iter_backward_sentence_start (GtkTextIter *iter)
+{
+  GtkTextIter tmp;
+  SentenceStatus status;
+
+  g_return_val_if_fail (iter, FALSE);
+
+  tmp = *iter;
+  status = _ide_vim_iter_backward_sentence_end (&tmp);
+
+  switch (status)
+    {
+    case SENTENCE_PARA:
+    case SENTENCE_OK:
+      {
+        GtkTextIter copy = tmp;
+
+        /*
+         * try to work forward to first non-whitespace char.
+         * if we land where we started, discard the walk.
+         */
+        while (g_unichar_isspace (gtk_text_iter_get_char (&copy)))
+          if (!gtk_text_iter_forward_char (&copy))
+            break;
+        if (gtk_text_iter_compare (&copy, iter) < 0)
+          tmp = copy;
+        *iter = tmp;
+
+        return TRUE;
+      }
+
+    case SENTENCE_FAILED:
+    default:
+      gtk_text_buffer_get_start_iter (gtk_text_iter_get_buffer (iter), iter);
+      return FALSE;
+    }
+}
diff --git a/libide/ide-vim-iter.h b/libide/ide-vim-iter.h
new file mode 100644
index 0000000..85ba31d
--- /dev/null
+++ b/libide/ide-vim-iter.h
@@ -0,0 +1,33 @@
+/* ide-vim-iter.h
+ *
+ * Copyright (C) 2015 Christian Hergert <christian hergert me>
+ *
+ * This file is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This file 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
+ * Lesser 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/>.
+ */
+
+#ifndef IDE_VIM_ITER_H
+#define IDE_VIM_ITER_H
+
+#include <gtk/gtk.h>
+
+G_BEGIN_DECLS
+
+gboolean _ide_vim_iter_backward_paragraph_start (GtkTextIter *iter);
+gboolean _ide_vim_iter_forward_paragraph_end    (GtkTextIter *iter);
+gboolean _ide_vim_iter_backward_sentence_start  (GtkTextIter *iter);
+gboolean _ide_vim_iter_forward_sentence_end     (GtkTextIter *iter);
+
+G_END_DECLS
+
+#endif /* IDE_VIM_ITER_H */