1 files changed, 483 insertions, 0 deletions
diff --git a/data/lineup-parameters.c b/data/lineup-parameters.c
new file mode 100644
index 0000000..51a01e1
--- /dev/null
+++ b/data/lineup-parameters.c
@@ -0,0 +1,483 @@
+/*
+ * This file is part of gnome-c-utils.
+ *
+ * Copyright © 2013 Sébastien Wilmet <swilmet@gnome.org>
+ *
+ * gnome-c-utils 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.
+ *
+ * gnome-c-utils 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 gnome-c-utils.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+/*
+ * Line up parameters of function declarations.
+ *
+ * Usage: lineup-parameters [file]
+ * If the file is not given, stdin is read.
+ * The result is printed to stdout.
+ *
+ * The restrictions:
+ * - The function name must be at column 0, followed by a space and an opening
+ *   parenthesis;
+ * - One parameter per line;
+ * - A paramater must follow certain rules (see the regex in the code), but it
+ *   doesn't accept all possibilities of the C language.
+ * - The opening curly brace ("{") of the function must also be at column 0.
+ *
+ * If one restriction is missing, the function declaration is not modified.
+ *
+ * Example:
+ *
+ * gboolean
+ * frobnitz (Frobnitz *frobnitz,
+ *           gint magic_number,
+ *           GError **error)
+ * {
+ *   ...
+ * }
+ *
+ * Becomes:
+ *
+ * gboolean
+ * frobnitz (Frobnitz  *frobnitz,
+ *           gint       magic_number,
+ *           GError   **error)
+ * {
+ *   ...
+ * }
+ */
+
+/*
+ * Use with Vim:
+ *
+ * Although this script can be used in Vim (or other text editors), a Vim plugin
+ * exists:
+ * http://damien.lespiau.name/blog/2009/12/07/aligning-c-function-parameters-with-vim/
+ *
+ * You can use a selection:
+ * - place the cursor at the function's name;
+ * - press V to start the line selection;
+ * - press ]] to go to the "{";
+ * - type ":" followed by "!lineup-parameters".
+ *
+ * Note: the "{" is required in the selection, to detect that we are in a
+ * function declaration.
+ *
+ * You can easily map these steps with a keybinding (F8 in the example below).
+ * Note that I'm not a Vim expert, so there is maybe a better way to configure
+ * this stuff.
+ *
+ * function! LineupParameters()
+ *         let l:winview = winsaveview()
+ *         execute "normal {V]]:!lineup-parameters\<CR>"
+ *         call winrestview(l:winview)
+ * endfunction
+ *
+ * autocmd Filetype c map <F8> :call LineupParameters()<CR>
+ */
+
+/* TODO support "..." vararg parameter. */
+
+#include <gio/gio.h>
+#include <gio/gunixinputstream.h>
+#include <stdlib.h>
+#include <string.h>
+#include <locale.h>
+#include <unistd.h>
+
+#define USE_TABS FALSE
+
+typedef struct
+{
+  gchar *type;
+  guint nb_stars;
+  gchar *name;
+} ParameterInfo;
+
+static void
+parameter_info_free (ParameterInfo *param_info)
+{
+  g_free (param_info->type);
+  g_free (param_info->name);
+  g_slice_free (ParameterInfo, param_info);
+}
+
+static gboolean
+match_function_name (const gchar  *line,
+                     gchar       **function_name,
+                     gint         *first_param_pos)
+{
+  static GRegex *regex = NULL;
+  GMatchInfo *match_info;
+  gint end_pos;
+  gboolean match = FALSE;
+
+  if (G_UNLIKELY (regex == NULL))
+    regex = g_regex_new ("^(\\w+) ?\\(", G_REGEX_OPTIMIZE, 0, NULL);
+
+  g_regex_match (regex, line, 0, &match_info);
+
+  if (g_match_info_matches (match_info) &&
+      g_match_info_fetch_pos (match_info, 1, NULL, &end_pos) &&
+      g_match_info_fetch_pos (match_info, 0, NULL, first_param_pos))
+    {
+      match = TRUE;
+
+      if (function_name != NULL)
+        *function_name = g_strndup (line, end_pos);
+    }
+
+  g_match_info_free (match_info);
+  return match;
+}
+
+static gboolean
+match_parameter (gchar          *line,
+                 ParameterInfo **info,
+                 gboolean       *is_last_parameter)
+{
+  static GRegex *regex = NULL;
+  GMatchInfo *match_info;
+  gint start_pos = 0;
+
+  if (G_UNLIKELY (regex == NULL))
+    regex = g_regex_new ("^\\s*(?<type>(const\\s+)?\\w+)\\s+(?<stars>\\**)\\s*(?<name>\\w+)\\s*(?<end>,|\\))\\s*$",
+                         G_REGEX_OPTIMIZE,
+                         0,
+                         NULL);
+
+  if (is_last_parameter != NULL)
+    *is_last_parameter = FALSE;
+
+  match_function_name (line, NULL, &start_pos);
+
+  g_regex_match (regex, line + start_pos, 0, &match_info);
+
+  if (!g_match_info_matches (match_info))
+    {
+      g_match_info_free (match_info);
+      return FALSE;
+    }
+
+  if (info != NULL)
+    {
+      gchar *stars;
+
+      *info = g_slice_new0 (ParameterInfo);
+
+      (*info)->type = g_match_info_fetch_named (match_info, "type");
+      (*info)->name = g_match_info_fetch_named (match_info, "name");
+      g_assert ((*info)->type != NULL);
+      g_assert ((*info)->name != NULL);
+
+      stars = g_match_info_fetch_named (match_info, "stars");
+      (*info)->nb_stars = strlen (stars);
+      g_free (stars);
+    }
+
+  if (is_last_parameter != NULL)
+    {
+      gchar *end = g_match_info_fetch_named (match_info, "end");
+      *is_last_parameter = g_str_equal (end, ")");
+      g_free (end);
+    }
+
+  g_match_info_free (match_info);
+  return TRUE;
+}
+
+static gboolean
+match_opening_curly_brace (const gchar *line)
+{
+  static GRegex *regex = NULL;
+
+  if (G_UNLIKELY (regex == NULL))
+    regex = g_regex_new ("^{\\s*$", G_REGEX_OPTIMIZE, 0, NULL);
+
+  return g_regex_match (regex, line, 0, NULL);
+}
+
+/* Returns the number of lines that take the function declaration.
+ * Returns 0 if not a function declaration. */
+static guint
+get_function_declaration_length (gchar **lines)
+{
+  guint nb_lines = 1;
+  gchar **cur_line = lines;
+
+  while (*cur_line != NULL)
+    {
+      gboolean match_param;
+      gboolean is_last_param;
+
+      match_param = match_parameter (*cur_line, NULL, &is_last_param);
+
+      if (is_last_param)
+        {
+          gchar *next_line = *(cur_line + 1);
+
+          if (next_line == NULL ||
+              !match_opening_curly_brace (next_line))
+            return 0;
+
+          return nb_lines;
+        }
+
+      if (!match_param)
+        return 0;
+
+      nb_lines++;
+      cur_line++;
+    }
+  /* should not be reachable - but silences a compiler warning */
+  return 0;
+}
+
+static GSList *
+get_list_parameter_infos (gchar **lines,
+                          guint   length)
+{
+  GSList *list = NULL;
+  gint i;
+
+  for (i = length - 1; i >= 0; i--)
+    {
+      ParameterInfo *info = NULL;
+
+      match_parameter (lines[i], &info, NULL);
+      g_assert (info != NULL);
+
+      list = g_slist_prepend (list, info);
+    }
+
+  return list;
+}
+
+static void
+compute_spacing (GSList *parameter_infos,
+                 guint  *max_type_length,
+                 guint  *max_stars_length)
+{
+  GSList *l;
+  *max_type_length = 0;
+  *max_stars_length = 0;
+
+  for (l = parameter_infos; l != NULL; l = l->next)
+    {
+      ParameterInfo *info = l->data;
+      guint type_length = strlen (info->type);
+
+      if (type_length > *max_type_length)
+        *max_type_length = type_length;
+
+      if (info->nb_stars > *max_stars_length)
+        *max_stars_length = info->nb_stars;
+    }
+}
+
+static void
+print_parameter (ParameterInfo *info,
+                 guint          max_type_length,
+                 guint          max_stars_length)
+{
+  gint type_length;
+  gint nb_spaces;
+  gchar *spaces;
+  gchar *stars;
+
+  g_print ("%s", info->type);
+
+  type_length = strlen (info->type);
+  nb_spaces = max_type_length - type_length;
+  g_assert (nb_spaces >= 0);
+
+  spaces = g_strnfill (nb_spaces, ' ');
+  g_print ("%s ", spaces);
+  g_free (spaces);
+
+  nb_spaces = max_stars_length - info->nb_stars;
+  g_assert (nb_spaces >= 0);
+  spaces = g_strnfill (nb_spaces, ' ');
+  g_print ("%s", spaces);
+  g_free (spaces);
+
+  stars = g_strnfill (info->nb_stars, '*');
+  g_print ("%s", stars);
+  g_free (stars);
+
+  g_print ("%s", info->name);
+}
+
+static void
+print_function_declaration (gchar **lines,
+                            guint   length)
+{
+  gchar **cur_line = lines;
+  gchar *function_name;
+  gint nb_spaces_to_parenthesis;
+  GSList *parameter_infos;
+  GSList *l;
+  guint max_type_length;
+  guint max_stars_length;
+  gchar *spaces;
+
+  if (!match_function_name (*cur_line, &function_name, NULL))
+    g_error ("The line doesn't match a function name.");
+
+  g_print ("%s (", function_name);
+
+  nb_spaces_to_parenthesis = strlen (function_name) + 2;
+
+  if (USE_TABS)
+    {
+      gchar *tabs = g_strnfill (nb_spaces_to_parenthesis / 8, '\t');
+      gchar *spaces_after_tabs = g_strnfill (nb_spaces_to_parenthesis % 8, ' ');
+
+      spaces = g_strdup_printf ("%s%s", tabs, spaces_after_tabs);
+
+      g_free (tabs);
+      g_free (spaces_after_tabs);
+    }
+  else
+    {
+      spaces = g_strnfill (nb_spaces_to_parenthesis, ' ');
+    }
+
+  parameter_infos = get_list_parameter_infos (lines, length);
+  compute_spacing (parameter_infos, &max_type_length, &max_stars_length);
+
+  for (l = parameter_infos; l != NULL; l = l->next)
+    {
+      ParameterInfo *info = l->data;
+
+      if (l != parameter_infos)
+        g_print ("%s", spaces);
+
+      print_parameter (info, max_type_length, max_stars_length);
+
+      if (l->next != NULL)
+        g_print (",\n");
+    }
+
+  g_print (")\n");
+
+  g_free (function_name);
+  g_free (spaces);
+  g_slist_free_full (parameter_infos, (GDestroyNotify)parameter_info_free);
+}
+
+static void
+parse_contents (gchar **lines)
+{
+  gchar **cur_line = lines;
+
+  /* Skip the empty last line, to avoid adding an extra \n. */
+  for (cur_line = lines; cur_line[0] != NULL && cur_line[1] != NULL; cur_line++)
+    {
+      guint length;
+
+      if (!match_function_name (*cur_line, NULL, NULL))
+        {
+          g_print ("%s\n", *cur_line);
+          continue;
+        }
+
+      length = get_function_declaration_length (cur_line);
+
+      if (length == 0)
+        {
+          g_print ("%s\n", *cur_line);
+          continue;
+        }
+
+      print_function_declaration (cur_line, length);
+
+      cur_line += length - 1;
+    }
+}
+
+static gchar *
+get_file_contents (gchar *arg)
+{
+  GFile *file;
+  gchar *path;
+  gchar *contents;
+  GError *error = NULL;
+
+  file = g_file_new_for_commandline_arg (arg);
+  path = g_file_get_path (file);
+  g_file_get_contents (path, &contents, NULL, &error);
+
+  if (error != NULL)
+    g_error ("Impossible to get file contents: %s", error->message);
+
+  g_object_unref (file);
+  g_free (path);
+  return contents;
+}
+
+static gchar *
+get_stdin_contents (void)
+{
+  GInputStream *stream;
+  GString *string;
+  GError *error = NULL;
+
+  stream = g_unix_input_stream_new (STDIN_FILENO, FALSE);
+  string = g_string_new ("");
+
+  while (TRUE)
+    {
+      gchar buffer[4097] = { '\0' };
+      gssize nb_bytes_read = g_input_stream_read (stream, buffer, 4096, NULL, &error);
+
+      if (nb_bytes_read == 0)
+        break;
+
+      if (error != NULL)
+        g_error ("Impossible to read stdin: %s", error->message);
+
+      g_string_append (string, buffer);
+    }
+
+  g_input_stream_close (stream, NULL, NULL);
+  g_object_unref (stream);
+
+  return g_string_free (string, FALSE);
+}
+
+gint
+main (gint   argc,
+      gchar *argv[])
+{
+  gchar *contents;
+  gchar **contents_lines;
+
+  setlocale (LC_ALL, "");
+
+  if (argc > 2)
+    {
+      g_printerr ("Usage: %s [file]\n", argv[0]);
+      return EXIT_FAILURE;
+    }
+
+  if (argc == 2)
+    contents = get_file_contents (argv[1]);
+  else
+    contents = get_stdin_contents ();
+
+  contents_lines = g_strsplit (contents, "\n", 0);
+  g_free (contents);
+
+  parse_contents (contents_lines);
+
+  return EXIT_SUCCESS;
+}