# HG changeset patch
# User J. Ali Harlow <ali@juiblex.co.uk>
# Date 1528383369 -3600
# Node ID 2ba231a7973ef32c56207b0e1d288b4c70304735
# Parent  9f4b672bd85c66feb629086bedc98fdceb419870
PloverPackageSet shouldn't try and acquire the same razor lock twice

diff -r 9f4b672bd85c -r 2ba231a7973e plover/packageset.c
--- a/plover/packageset.c	Tue Jun 05 17:21:56 2018 +0100
+++ b/plover/packageset.c	Thu Jun 07 15:56:09 2018 +0100
@@ -62,25 +62,15 @@
 
 static void plover_package_set_dispose(GObject *obj)
 {
-    PloverPackageSetPrivate *priv=PLOVER_PACKAGE_SET_GET_PRIVATE(obj);
+    PloverPackageSet *set=PLOVER_PACKAGE_SET(obj);
+    PloverPackageSetPrivate *priv=PLOVER_PACKAGE_SET_GET_PRIVATE(set);
     if (priv->packages)
     {
 	g_slist_foreach(priv->packages,(GFunc)g_object_unref,NULL);
 	g_slist_free(priv->packages);
 	priv->packages=NULL;
     }
-    if (priv->set)
-    {
-	razor_set_unref(priv->set);
-	priv->set=NULL;
-    }
-    if (priv->root)
-    {
-	g_free(priv->root_uri);
-	priv->root_uri=NULL;
-	razor_root_close(priv->root);
-	priv->root=NULL;
-    }
+    plover_package_set_close(set);
     G_OBJECT_CLASS(plover_package_set_parent_class)->dispose(obj);
 }
 
@@ -113,22 +103,51 @@
     PloverPackageSetPrivate *priv;
     g_return_if_fail(PLOVER_IS_PACKAGE_SET(set));
     priv=PLOVER_PACKAGE_SET_GET_PRIVATE(set);
+    if (priv->set)
+    {
+	razor_set_unref(priv->set);
+	priv->set=NULL;
+    }
     if (priv->root)
     {
 	razor_root_close(priv->root);
 	priv->root=NULL;
     }
+    if (priv->root_uri)
+    {
+	g_free(priv->root_uri);
+	priv->root_uri=NULL;
+    }
 }
 
 gboolean plover_package_set_open(PloverPackageSet *set,const char *root_uri,
   gboolean exclusive,GError **err)
 {
+    gboolean incompatible_lock=FALSE;
     struct razor_root *root=NULL;
     struct razor_set *system=NULL;
     PloverPackageSetPrivate *priv;
     struct razor_error *error=NULL;
     g_return_val_if_fail(PLOVER_IS_PACKAGE_SET(set),FALSE);
     g_return_val_if_fail(plover__uri_validate(root_uri),FALSE);
+    priv=PLOVER_PACKAGE_SET_GET_PRIVATE(set);
+    /*
+     * If we're opening a different root_uri, then we can simply open the
+     * new root first and then close the old root if we're successful.
+     * Otherwise, if we're changing the lock type we have to close the
+     * old lock first which allows for the possibility of failing to
+     * re-open the old root on failure. That's unfortunate but appears
+     * unavoidable; MS-Windows doesn't appear to have the ability to
+     * either upgrade or downgrade a file lock.
+     */
+    if (!g_strcmp0(root_uri,priv->root_uri))
+    {
+	incompatible_lock=!priv->root!=!exclusive;
+	if (incompatible_lock)
+	    plover_package_set_close(set);
+	else
+	    return TRUE;
+    }
     if (exclusive)
     {
 	root=razor_root_open(root_uri,NULL);
@@ -150,6 +169,8 @@
 	    if (!root)                        
 	    {
 		plover_propagate_razor_error(err,error);
+		if (incompatible_lock)
+		    (void)plover_package_set_open(set,root_uri,!exclusive,NULL);
 		return FALSE;
 	    }
 	}
@@ -164,23 +185,14 @@
 	g_set_error_literal(err,PLOVER_RAZOR_ERROR,RAZOR_GENERAL_ERROR_FAILED,
 	  razor_error_get_msg(error));
 	razor_error_free(error);
+	if (incompatible_lock)
+	    (void)plover_package_set_open(set,root_uri,!exclusive,NULL);
 	return FALSE;
     }
-    priv=PLOVER_PACKAGE_SET_GET_PRIVATE(set);
-    if (priv->set)
-    {
-	razor_set_unref(priv->set);
-	priv->set=NULL;
-    }
-    if (priv->root)
-    {
-	razor_root_close(priv->root);
-	priv->root=NULL;
-    }
-    g_free(priv->root_uri);
-    priv->root_uri=g_strdup(root_uri);
+    plover_package_set_close(set);
     priv->root=root;
     priv->set=system;
+    priv->root_uri=g_strdup(root_uri);
     return TRUE;
 }