@ -1,3 +1,4 @@
# include <ccan/asort/asort.h>
# include <ccan/io/io.h>
# include <ccan/list/list.h>
# include <common/configdir.h>
@ -401,25 +402,9 @@ void plugin_hook_add_deps(struct plugin_hook *hook,
add_deps ( & h - > after , buffer , after ) ;
}
/* From https://en.wikipedia.org/wiki/Topological_sorting#Kahn's_algorithm
* ( https : //creativecommons.org/licenses/by-sa/3.0/):
* L ← Empty list that will contain the sorted elements
* S ← Set of all nodes with no incoming edge
*
* while S is not empty do
* remove a node n from S
* add n to L
* for each node m with an edge e from n to m do
* remove edge e from the graph
* if m has no other incoming edges then
* insert m into S
*
* if graph has edges then
* return error ( graph has at least one cycle )
* else
* return L ( a topologically sorted order )
*/
struct hook_node {
/* Is this copied into the ordered array yet? */
bool finished ;
struct hook_instance * hook ;
size_t num_incoming ;
struct hook_node * * outgoing ;
@ -434,16 +419,33 @@ static struct hook_node *find_hook(struct hook_node *graph, const char *name)
return NULL ;
}
/* Sometimes naive is best. */
static struct hook_node * get_best_candidate ( struct hook_node * graph )
{
struct hook_node * best = NULL ;
for ( size_t i = 0 ; i < tal_count ( graph ) ; i + + ) {
if ( graph [ i ] . finished )
continue ;
if ( graph [ i ] . num_incoming ! = 0 )
continue ;
if ( ! best
| | best - > hook - > plugin - > index > graph [ i ] . hook - > plugin - > index )
best = & graph [ i ] ;
}
return best ;
}
static struct plugin * * plugin_hook_make_ordered ( const tal_t * ctx ,
struct plugin_hook * hook )
{
struct hook_node * graph ;
struct hook_node * * l , * * s ;
struct plugin * * ret ;
struct hook_node * graph , * n ;
struct hook_instance * * done ;
/* Populate graph nodes */
graph = tal_arr ( tmpctx , struct hook_node , tal_count ( hook - > hooks ) ) ;
for ( size_t i = 0 ; i < tal_count ( graph ) ; i + + ) {
graph [ i ] . finished = false ;
graph [ i ] . hook = hook - > hooks [ i ] ;
graph [ i ] . num_incoming = 0 ;
graph [ i ] . outgoing = tal_arr ( graph , struct hook_node * , 0 ) ;
@ -481,45 +483,26 @@ static struct plugin **plugin_hook_make_ordered(const tal_t *ctx,
}
}
/* Populate array of ready-to-go nodes. */
s = tal_arr ( graph , struct hook_node * , 0 ) ;
for ( size_t i = 0 ; i < tal_count ( graph ) ; i + + ) {
if ( graph [ i ] . num_incoming = = 0 )
tal_arr_expand ( & s , & graph [ i ] ) ;
done = tal_arr ( tmpctx , struct hook_instance * , 0 ) ;
while ( ( n = get_best_candidate ( graph ) ) ! = NULL ) {
tal_arr_expand ( & done , n - > hook ) ;
n - > finished = true ;
for ( size_t i = 0 ; i < tal_count ( n - > outgoing ) ; i + + )
n - > outgoing [ i ] - > num_incoming - - ;
}
l = tal_arr ( graph , struct hook_node * , 0 ) ;
while ( tal_count ( s ) ) {
struct hook_node * n = s [ 0 ] ;
tal_arr_expand ( & l , n ) ;
tal_arr_remove ( & s , 0 ) ;
/* for each node m with an edge e from n to m do
* remove edge e from the graph
* if m has no other incoming edges then
* insert m into S
*/
for ( size_t i = 0 ; i < tal_count ( n - > outgoing ) ; i + + ) {
if ( - - n - > outgoing [ i ] - > num_incoming = = 0 )
tal_arr_expand ( & s , n - > outgoing [ i ] ) ;
if ( tal_count ( done ) ! = tal_count ( hook - > hooks ) ) {
struct plugin * * ret = tal_arr ( ctx , struct plugin * , 0 ) ;
for ( size_t i = 0 ; i < tal_count ( graph ) ; i + + ) {
if ( ! graph [ i ] . finished )
tal_arr_expand ( & ret , graph [ i ] . hook - > plugin ) ;
}
}
/* Check for any left over: these cannot be loaded. */
ret = tal_arr ( ctx , struct plugin * , 0 ) ;
for ( size_t i = 0 ; i < tal_count ( graph ) ; i + + ) {
if ( graph [ i ] . num_incoming )
tal_arr_expand ( & ret , graph [ i ] . hook - > plugin ) ;
}
if ( tal_count ( ret ) ! = 0 )
return ret ;
}
/* Success! Write them back in order. */
assert ( tal_count ( l ) = = tal_count ( hook - > hooks ) ) ;
for ( size_t i = 0 ; i < tal_count ( hook - > hooks ) ; i + + )
hook - > hooks [ i ] = l [ i ] - > hook ;
return tal_free ( ret ) ;
/* Success! Copy ordered hooks back. */
memcpy ( hook - > hooks , done , tal_bytelen ( hook - > hooks ) ) ;
return NULL ;
}
/* Plugins could fail due to multiple hooks, but only add once. */
Rusty Russell
4 years ago
neil saitug