[devhelp] DhLink: add match_relative_url()

[Sébastien Wilmet <swilmet src gnome org>]

commit 4c9092ddd2ead7063cc022a32dca71b755a59895
Author: Sébastien Wilmet <swilmet gnome org>
Date:   Wed Dec 6 13:24:50 2017 +0100

    DhLink: add match_relative_url()
    
    dh_link_get_file_name() returns the empty string for the book top-level
    link. find_equivalent_local_uri() in dh-window.c calls g_strcmp0() on
    the string returned by dh_link_get_file_name(), to see if the relative
    URL matches.
    
    So currently find_equivalent_local_uri() will find an equivalent for:
    https://developer.gnome.org/glib/unstable/
    but not for:
    https://developer.gnome.org/glib/unstable/index.html
    
    With dh_link_match_relative_url(), it will find an equivalent for both.

 docs/reference/devhelp-sections.txt |    1 +
 src/dh-link.c                       |   39 +++++++++++++++++++++++++++++++++++
 src/dh-link.h                       |    3 ++
 3 files changed, 43 insertions(+), 0 deletions(-)
---
diff --git a/docs/reference/devhelp-sections.txt b/docs/reference/devhelp-sections.txt
index 4b7203c..15f1bdf 100644
--- a/docs/reference/devhelp-sections.txt
+++ b/docs/reference/devhelp-sections.txt
@@ -117,6 +117,7 @@ dh_link_get_flags
 dh_link_set_flags
 dh_link_get_name
 dh_link_get_file_name
+dh_link_match_relative_url
 dh_link_get_uri
 dh_link_get_book_name
 dh_link_get_book_id
diff --git a/src/dh-link.c b/src/dh-link.c
index 30e2808..b1710b4 100644
--- a/src/dh-link.c
+++ b/src/dh-link.c
@@ -265,6 +265,45 @@ dh_link_get_file_name (DhLink *link)
 }
 
 /**
+ * dh_link_match_relative_url:
+ * @link: a #DhLink.
+ * @relative_url: an URL relative to the book base path. Can contain an anchor.
+ *
+ * Returns: whether the relative URL of @link matches with @relative_url. There
+ * is a special case for the index.html page, it can also match the empty
+ * string.
+ * Since: 3.28
+ */
+gboolean
+dh_link_match_relative_url (DhLink      *link,
+                            const gchar *relative_url)
+{
+        g_return_val_if_fail (link != NULL, FALSE);
+        g_return_val_if_fail (link->relative_url != NULL, FALSE);
+        g_return_val_if_fail (relative_url != NULL, FALSE);
+
+        if (g_str_equal (link->relative_url, relative_url))
+                return TRUE;
+
+        /* Special case for index.html, can also match the empty string.
+         * Example of full URLs:
+         * file:///usr/share/gtk-doc/html/glib/
+         * file:///usr/share/gtk-doc/html/glib/index.html
+         *
+         * This supports only the root index.html page of a DhBook, this doesn't
+         * support index.html inside a sub-directory, if the relative_url
+         * contains a sub-directory. But apparently GTK-Doc doesn't create
+         * sub-directories, all the *.html pages are in the same directory.
+         */
+        if (relative_url[0] == '\0')
+                return g_str_equal (link->relative_url, "index.html");
+        else if (link->relative_url[0] == '\0')
+                return g_str_equal (relative_url, "index.html");
+
+        return FALSE;
+}
+
+/**
  * dh_link_get_uri:
  * @link: a #DhLink.
  *
diff --git a/src/dh-link.h b/src/dh-link.h
index dddb83d..51093a0 100644
--- a/src/dh-link.h
+++ b/src/dh-link.h
@@ -93,6 +93,9 @@ const gchar *dh_link_get_name           (DhLink        *link);
 
 const gchar *dh_link_get_file_name      (DhLink        *link);
 
+gboolean     dh_link_match_relative_url (DhLink        *link,
+                                         const gchar   *relative_url);
+
 gchar *      dh_link_get_uri            (DhLink        *link);
 
 const gchar *dh_link_get_book_name      (DhLink        *link);