Index: subversion/include/svn_repos.h
===================================================================
--- subversion/include/svn_repos.h	(revision 25836)
+++ subversion/include/svn_repos.h	(working copy)
@@ -1026,9 +1026,33 @@
  * them; instead, immediately stop traversing history and return
  * SVN_NO_ERROR.
  *
- * @since New in 1.1.
+ * If @a cancel_func is non-NULL, invoke it passing @a cancel_baton at
+ * various places during the operation.
+ *
+ * @since New in 1.5.
  */
 svn_error_t *
+svn_repos_history3(svn_fs_t *fs,
+                   const char *path,
+                   svn_repos_history_func_t history_func,
+                   void *history_baton,
+                   svn_repos_authz_func_t authz_read_func,
+                   void *authz_read_baton,
+                   svn_revnum_t start,
+                   svn_revnum_t end,
+                   svn_cancel_func_t cancel_func,
+                   void *cancel_baton,
+                   svn_boolean_t cross_copies,
+                   apr_pool_t *pool);
+
+
+/**
+ * Same as svn_repos_history3(), but with @a cancel_func always set to
+ * @c NULL.
+ *
+ * @deprecated Provided for backward compatibility with the 1.1 API.
+ */
+svn_error_t *
 svn_repos_history2(svn_fs_t *fs,
                    const char *path,
                    svn_repos_history_func_t history_func,
Index: subversion/svnlook/main.c
===================================================================
--- subversion/svnlook/main.c	(revision 25836)
+++ subversion/svnlook/main.c	(working copy)
@@ -1390,8 +1390,9 @@
      copies. */
   args.fs = c->fs;
   args.show_ids = show_ids;
-  SVN_ERR(svn_repos_history2(c->fs, path, print_history, &args,
-                             NULL, NULL, 0, c->rev_id, 1, pool));
+  SVN_ERR(svn_repos_history3(c->fs, path, print_history, &args,
+                             NULL, NULL, 0, c->rev_id, NULL, NULL,
+                             TRUE, pool));
   return SVN_NO_ERROR;
 }
 
Index: subversion/libsvn_repos/rev_hunt.c
===================================================================
--- subversion/libsvn_repos/rev_hunt.c	(revision 25836)
+++ subversion/libsvn_repos/rev_hunt.c	(working copy)
@@ -193,6 +193,7 @@
 
 
 
+/* Deprecated. */
 svn_error_t *
 svn_repos_history2(svn_fs_t *fs,
                    const char *path,
@@ -205,12 +206,34 @@
                    svn_boolean_t cross_copies,
                    apr_pool_t *pool)
 {
+  return svn_repos_history3(fs, path, history_func, history_baton,
+                            authz_read_func, authz_read_baton,
+                            start, end, NULL, NULL, cross_copies, pool);
+}
+
+
+
+svn_error_t *
+svn_repos_history3(svn_fs_t *fs,
+                   const char *path,
+                   svn_repos_history_func_t history_func,
+                   void *history_baton,
+                   svn_repos_authz_func_t authz_read_func,
+                   void *authz_read_baton,
+                   svn_revnum_t start,
+                   svn_revnum_t end,
+                   svn_cancel_func_t cancel_func,
+                   void *cancel_baton,
+                   svn_boolean_t cross_copies,
+                   apr_pool_t *pool)
+{
   svn_fs_history_t *history;
   apr_pool_t *oldpool = svn_pool_create(pool);
   apr_pool_t *newpool = svn_pool_create(pool);
   const char *history_path;
   svn_revnum_t history_rev;
   svn_fs_root_t *root;
+  int count = 0;
 
   /* Validate the revisions. */
   if (! SVN_IS_VALID_REVNUM(start))
@@ -290,6 +313,9 @@
       tmppool = oldpool;
       oldpool = newpool;
       newpool = tmppool;
+
+      if (cancel_func)
+        SVN_ERR((*cancel_func)(cancel_baton));
     }
   while (history); /* shouldn't hit this */