[tepl] Utils: add get_file_extension() and get_file_shortname()

[Sébastien Wilmet <swilmet src gnome org>]

commit 8c00726eed3f03f3a23f8d2ef49d1035c8c890d7
Author: Sébastien Wilmet <swilmet gnome org>
Date:   Mon Nov 18 10:27:21 2019 +0100

    Utils: add get_file_extension() and get_file_shortname()
    
    Copied from gnome-latex, it will be used there.

 docs/reference/tepl-4.0-sections.txt |  2 +
 tepl/tepl-utils.c                    | 73 ++++++++++++++++++++++++++++++++++++
 tepl/tepl-utils.h                    |  4 ++
 testsuite/test-utils.c               | 50 ++++++++++++++++++++++++
 4 files changed, 129 insertions(+)
---
diff --git a/docs/reference/tepl-4.0-sections.txt b/docs/reference/tepl-4.0-sections.txt
index 72d8933..e4795f5 100644
--- a/docs/reference/tepl-4.0-sections.txt
+++ b/docs/reference/tepl-4.0-sections.txt
@@ -389,6 +389,8 @@ tepl_notebook_get_type
 <FILE>utils</FILE>
 tepl_utils_str_middle_truncate
 tepl_utils_str_end_truncate
+tepl_utils_get_file_extension
+tepl_utils_get_file_shortname
 </SECTION>
 
 <SECTION>
diff --git a/tepl/tepl-utils.c b/tepl/tepl-utils.c
index 0a6cad9..45a609b 100644
--- a/tepl/tepl-utils.c
+++ b/tepl/tepl-utils.c
@@ -131,6 +131,79 @@ tepl_utils_str_end_truncate (const gchar *str,
        return str_truncate (str, truncate_length, FALSE);
 }
 
+static gint
+get_extension_position (const gchar *filename)
+{
+       const gchar *pos;
+       gint length;
+
+       if (filename == NULL)
+       {
+               return 0;
+       }
+
+       length = strlen (filename);
+       pos = filename + length;
+       g_assert (pos[0] == '\0');
+
+       while (TRUE)
+       {
+               pos = g_utf8_find_prev_char (filename, pos);
+
+               if (pos == NULL || pos[0] == '/')
+               {
+                       break;
+               }
+
+               if (pos[0] == '.')
+               {
+                       return pos - filename;
+               }
+       }
+
+       return length;
+}
+
+/**
+ * tepl_utils_get_file_extension:
+ * @filename: a filename.
+ *
+ * Examples:
+ * - "file.pdf" returns ".pdf".
+ * - "file.PDF" returns ".pdf".
+ * - "file.tar.gz" returns ".gz".
+ * - "path/to/file.pdf" returns ".pdf".
+ * - "file" (without an extension) returns "" (the empty string).
+ *
+ * Returns: the @filename's extension with the dot, in lowercase. Free with
+ * g_free().
+ * Since: 4.4
+ */
+gchar *
+tepl_utils_get_file_extension (const gchar *filename)
+{
+       gint pos = get_extension_position (filename);
+
+       return g_ascii_strdown (filename + pos, -1);
+}
+
+/**
+ * tepl_utils_get_file_shortname:
+ * @filename: a filename.
+ *
+ * Returns @filename without its extension. With the “extension” having the same
+ * definition as in tepl_utils_get_file_extension(); in other words it returns
+ * the other part of @filename.
+ *
+ * Returns: the @filename without its extension. Free with g_free().
+ * Since: 4.4
+ */
+gchar *
+tepl_utils_get_file_shortname (const gchar *filename)
+{
+       return g_strndup (filename, get_extension_position (filename));
+}
+
 /*
  * _tepl_utils_replace_home_dir_with_tilde:
  * @filename: the filename.
diff --git a/tepl/tepl-utils.h b/tepl/tepl-utils.h
index 117b18d..b1b7342 100644
--- a/tepl/tepl-utils.h
+++ b/tepl/tepl-utils.h
@@ -38,6 +38,10 @@ gchar *              tepl_utils_str_end_truncate                     (const gchar *str,
 
 /* File utilities */
 
+gchar *                tepl_utils_get_file_extension                   (const gchar *filename);
+
+gchar *                tepl_utils_get_file_shortname                   (const gchar *filename);
+
 G_GNUC_INTERNAL
 gchar *                _tepl_utils_replace_home_dir_with_tilde         (const gchar *filename);
 
diff --git a/testsuite/test-utils.c b/testsuite/test-utils.c
index 6b2ee1d..85db02d 100644
--- a/testsuite/test-utils.c
+++ b/testsuite/test-utils.c
@@ -39,6 +39,54 @@ test_str_end_truncate (void)
        g_free (truncated_str);
 }
 
+static void
+test_get_file_extension (void)
+{
+       gchar *extension;
+
+       extension = tepl_utils_get_file_extension ("file.pdf");
+       g_assert_cmpstr (extension, ==, ".pdf");
+       g_free (extension);
+
+       extension = tepl_utils_get_file_extension ("file.PDF");
+       g_assert_cmpstr (extension, ==, ".pdf");
+       g_free (extension);
+
+       extension = tepl_utils_get_file_extension ("file.tar.gz");
+       g_assert_cmpstr (extension, ==, ".gz");
+       g_free (extension);
+
+       extension = tepl_utils_get_file_extension ("path/to/file.pdf");
+       g_assert_cmpstr (extension, ==, ".pdf");
+       g_free (extension);
+
+       extension = tepl_utils_get_file_extension ("file");
+       g_assert_cmpstr (extension, ==, "");
+       g_free (extension);
+}
+
+static void
+test_get_file_shortname (void)
+{
+       gchar *shortname;
+
+       shortname = tepl_utils_get_file_shortname ("file.txt");
+       g_assert_cmpstr (shortname, ==, "file");
+       g_free (shortname);
+
+       shortname = tepl_utils_get_file_shortname ("file.tar.gz");
+       g_assert_cmpstr (shortname, ==, "file.tar");
+       g_free (shortname);
+
+       shortname = tepl_utils_get_file_shortname ("file");
+       g_assert_cmpstr (shortname, ==, "file");
+       g_free (shortname);
+
+       shortname = tepl_utils_get_file_shortname ("dir.ext/blah");
+       g_assert_cmpstr (shortname, ==, "dir.ext/blah");
+       g_free (shortname);
+}
+
 static void
 test_replace_home_dir_with_tilde (void)
 {
@@ -120,6 +168,8 @@ main (gint    argc,
 
        g_test_add_func ("/utils/str-middle-truncate", test_str_middle_truncate);
        g_test_add_func ("/utils/str-end-truncate", test_str_end_truncate);
+       g_test_add_func ("/utils/get-file-extension", test_get_file_extension);
+       g_test_add_func ("/utils/get-file-shortname", test_get_file_shortname);
        g_test_add_func ("/utils/replace-home-dir-with-tilde", test_replace_home_dir_with_tilde);
        g_test_add_func ("/utils/decode-uri", test_decode_uri);
        g_test_add_func ("/utils/get-fallback-basename-for-display", test_get_fallback_basename_for_display);