Fix and enhance sorting of editor tabs based on pathnames

Simple sorting by comparing pathname strings is not enough, and produces
inconsistent results.  Files need to be grouped and sorted based on
their parent directories.  This update does that, and also imports
get_doc_folder() to notebook.c, and uses it, so that the results would
be exactly the same as the one in documents list.

src/notebook.c

@@ -34,6 +34,7 @@
 #include "geanyobject.h"
 #include "keybindings.h"
 #include "main.h"
+#include "project.h"
 #include "support.h"
 #include "ui_utils.h"
 #include "utils.h"
@@ -768,67 +769,177 @@ void notebook_remove_page(gint page_num)
 }
 
 
-gint compare_based_on_filename(gconstpointer a, gconstpointer b)
+static gint compare_docs_based_on_filename(gconstpointer a, gconstpointer b)
 {
-	GeanyDocument *doc_a, *doc_b;
-	gchar *basename_a, *basename_b;
-	gchar *key_a, *key_b;
-	gint cmp;
-
-	doc_a = *(GeanyDocument**) a;
-	doc_b = *(GeanyDocument**) b;
-	basename_a = g_path_get_basename(DOC_FILENAME(doc_a));
-	basename_b = g_path_get_basename(DOC_FILENAME(doc_b));
-	key_a = g_utf8_collate_key_for_filename(basename_a, -1);
-	key_b = g_utf8_collate_key_for_filename(basename_b, -1);
-	cmp = strcmp(key_a, key_b);
+	GeanyDocument *doc_a = *(GeanyDocument**) a;
+	GeanyDocument *doc_b = *(GeanyDocument**) b;
+	gchar *basename_a = g_path_get_basename(DOC_FILENAME(doc_a));
+	gchar *basename_b = g_path_get_basename(DOC_FILENAME(doc_b));
+	gchar *key_a = g_utf8_collate_key_for_filename(basename_a, -1);
+	gchar *key_b = g_utf8_collate_key_for_filename(basename_b, -1);
+	gint cmp = strcmp(key_a, key_b);
 	g_free(key_b);
 	g_free(key_a);
 	g_free(basename_b);
 	g_free(basename_a);
-
 	return cmp;
 }
 
 
-gint compare_based_on_filepath(gconstpointer a, gconstpointer b)
+/* Copied from sidebar.c.  We can place this in one place like utils.c. */
+static gboolean utils_filename_has_prefix(const gchar *str, const gchar *prefix)
+{
+	gchar *head = g_strndup(str, strlen(prefix));
+	gboolean ret = utils_filenamecmp(head, prefix) == 0;
+
+	g_free(head);
+	return ret;
+}
+
+
+/* Copied from sidebar.c.  We can place this in one place like utils.c,
+ * with a more formal naming convention. */
+static gchar *get_doc_folder(const gchar *path)
 {
-	GeanyDocument *doc_a, *doc_b;
-	gchar *key_a, *key_b;
-	gint cmp;
+	gchar *tmp_dirname = g_strdup(path);
+	gchar *project_base_path;
+	gchar *dirname = NULL;
+	const gchar *home_dir = g_get_home_dir();
+	const gchar *rest;
 
-	doc_a = *(GeanyDocument**) a;
-	doc_b = *(GeanyDocument**) b;
+	/* replace the project base path with the project name */
+	project_base_path = project_get_base_path();
 
-	key_a = g_utf8_collate_key_for_filename(DOC_FILENAME(doc_a), -1);
-	key_b = g_utf8_collate_key_for_filename(DOC_FILENAME(doc_b), -1);
-	cmp = strcmp(key_a, key_b);
+	if (project_base_path != NULL)
+	{
+		gsize len = strlen(project_base_path);
+
+		/* remove trailing separator so we can match base path exactly */
+		if (project_base_path[len-1] == G_DIR_SEPARATOR)
+			project_base_path[--len] = '\0';
+
+		/* check whether the dir name matches or uses the project base path */
+		if (utils_filename_has_prefix(tmp_dirname, project_base_path))
+		{
+			rest = tmp_dirname + len;
+			if (*rest == G_DIR_SEPARATOR || *rest == '\0')
+			{
+				dirname = g_strdup_printf("%s%s", app->project->name, rest);
+			}
+		}
+		g_free(project_base_path);
+	}
+	if (dirname == NULL)
+	{
+		dirname = tmp_dirname;
+
+		/* If matches home dir, replace with tilde */
+		if (!EMPTY(home_dir) && utils_filename_has_prefix(dirname, home_dir))
+		{
+			rest = dirname + strlen(home_dir);
+			if (*rest == G_DIR_SEPARATOR || *rest == '\0')
+			{
+				dirname = g_strdup_printf("~%s", rest);
+				g_free(tmp_dirname);
+			}
+		}
+	}
+	else
+		g_free(tmp_dirname);
+
+	return dirname;
+}
+
+
+static gint compare_path_strings(gconstpointer a, gconstpointer b)
+{
+	gchar *path_a = *(gchar**) a;
+	gchar *path_b = *(gchar**) b;
+	gchar *key_a = g_utf8_collate_key_for_filename(path_a, -1);
+	gchar *key_b = g_utf8_collate_key_for_filename(path_b, -1);
+	gint cmp = strcmp(key_a, key_b);;
 	g_free(key_b);
 	g_free(key_a);
-
 	return cmp;
 }
 
 
+static void sort_docs_based_on_pathname(GArray *docs)
+{
+	GArray *tmp_docs, *dir_names;
+	GHashTable *table;
+	GeanyDocument *doc;
+	guint i, j, docs_len, save_index = 0;
+	gchar *dirname, *tmp_dirname;
+
+	table = g_hash_table_new(g_str_hash, g_str_equal);
+	dir_names = g_array_new(FALSE, FALSE, sizeof(gchar*));
+	docs_len = docs->len;
+
+	for (i = 0; i < docs_len; ++i)
+	{
+		doc = g_array_index(docs, GeanyDocument*, i);
+		tmp_dirname = g_path_get_dirname(DOC_FILENAME(doc));
+		dirname = get_doc_folder(tmp_dirname);
+		g_free(tmp_dirname);
+		tmp_docs = g_hash_table_lookup(table, dirname);
+
+		if (tmp_docs == NULL)
+		{
+			tmp_docs = g_array_new(TRUE, TRUE, sizeof(GeanyDocument*));
+			g_hash_table_insert(table, dirname, tmp_docs);
+			g_array_append_val(dir_names, dirname);
+		}
+		else
+			g_free(dirname);
+
+		g_array_append_val(tmp_docs, doc);
+	}
+
+	g_array_sort(dir_names, compare_path_strings);
+
+	for (i = 0; i < dir_names->len; ++i)
+	{
+		dirname = g_array_index(dir_names, gchar*, i);
+		g_assert(dirname != NULL);
+		tmp_docs = g_hash_table_lookup(table, dirname);
+		g_array_sort(tmp_docs, compare_docs_based_on_filename);
+
+		for (j = 0; j < tmp_docs->len; ++j)
+		{
+			g_assert(save_index < docs_len);
+			doc = g_array_index(tmp_docs, GeanyDocument*, j);
+			g_array_index(docs, GeanyDocument*, save_index++) = doc;
+		}
+
+		g_array_free(tmp_docs, TRUE);
+		g_free(dirname);
+	}
+
+	g_assert(save_index == docs_len);
+	g_array_free(dir_names, TRUE);
+	g_hash_table_destroy(table);
+}
+
+
 void notebook_sort_tabs(NotebookTabSortMethod method)
 {
 	GArray *docs;
 	GeanyDocument* doc;
 	GtkWidget *child;
-	guint i, size = 0;
+	guint i;
 
 	docs = g_array_new(FALSE, TRUE, sizeof(GeanyDocument*));
 
 	foreach_document(i)
-	{
 		g_array_append_val(docs, documents[i]);
-		++size;
-	}
 
-	g_array_sort(docs, method == NOTEBOOK_TAB_SORT_FILENAME ?
-		compare_based_on_filename : compare_based_on_filepath);
+	if (method == NOTEBOOK_TAB_SORT_FILENAME)
+		g_array_sort(docs, compare_docs_based_on_filename);
+	else
+		sort_docs_based_on_pathname(docs);
 
-	for (i = 0; i < size; ++i)
+	for (i = 0; i < docs->len; ++i)
 	{
 		doc = g_array_index(docs, GeanyDocument*, i);
 		child = document_get_notebook_child(doc);