/*
--
-- KEEPER.C
--
-- Keeper state logic
--
-- This code is read in for each "keeper state", which are the hidden, inter-
-- mediate data stores used by Lanes inter-state communication objects.
--
-- Author: Benoit Germain <bnt.germain@gmail.com>
--
-- C implementation replacement of the original keeper.lua
--
--[[
===============================================================================
Copyright (C) 2011-2013 Benoit Germain <bnt.germain@gmail.com>
Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in
all copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
THE SOFTWARE.
===============================================================================
]]--
*/
#include <string.h>
#include <stdio.h>
#include <stdlib.h>
#include <ctype.h>
#include <assert.h>
#include "keeper.h"
#include "compat.h"
#include "tools.h"
#include "state.h"
#include "universe.h"
#include "uniquekey.h"
//###################################################################################
// Keeper implementation
//###################################################################################
#ifndef __min
#define __min( a, b) (((a) < (b)) ? (a) : (b))
#endif // __min
typedef struct
{
lua_Integer first;
lua_Integer count;
lua_Integer limit;
} keeper_fifo;
static int const CONTENTS_TABLE = 1;
// replaces the fifo ud by its uservalue on the stack
static keeper_fifo* prepare_fifo_access( lua_State* L, int idx_)
{
keeper_fifo* fifo = (keeper_fifo*) lua_touserdata( L, idx_);
if( fifo != NULL)
{
idx_ = lua_absindex( L, idx_);
STACK_GROW( L, 1);
// we can replace the fifo userdata in the stack without fear of it being GCed, there are other references around
lua_getiuservalue( L, idx_, CONTENTS_TABLE);
lua_replace( L, idx_);
}
return fifo;
}
// in: nothing
// out: { first = 1, count = 0, limit = -1}
static void fifo_new( lua_State* L)
{
keeper_fifo* fifo;
STACK_GROW( L, 2);
// a fifo full userdata has one uservalue, the table that holds the actual fifo contents
fifo = (keeper_fifo*)lua_newuserdatauv( L, sizeof( keeper_fifo), 1);
fifo->first = 1;
fifo->count = 0;
fifo->limit = -1;
lua_newtable( L);
lua_setiuservalue( L, -2, CONTENTS_TABLE);
}
// in: expect fifo ... on top of the stack
// out: nothing, removes all pushed values from the stack
static void fifo_push( lua_State* L, keeper_fifo* fifo_, lua_Integer count_)
{
int const idx = lua_gettop( L) - (int) count_;
lua_Integer start = fifo_->first + fifo_->count - 1;
lua_Integer i;
// pop all additional arguments, storing them in the fifo
for( i = count_; i >= 1; -- i)
{
// store in the fifo the value at the top of the stack at the specified index, popping it from the stack
lua_rawseti( L, idx, (int)(start + i));
}
fifo_->count += count_;
}
// in: fifo
// out: ...|nothing
// expects exactly 1 value on the stack!
// currently only called with a count of 1, but this may change in the future
// function assumes that there is enough data in the fifo to satisfy the request
static void fifo_peek( lua_State* L, keeper_fifo* fifo_, lua_Integer count_)
{
lua_Integer i;
STACK_GROW( L, count_);
for( i = 0; i < count_; ++ i)
{
lua_rawgeti( L, 1, (int)( fifo_->first + i));
}
}
// in: fifo
// out: remove the fifo from the stack, push as many items as required on the stack (function assumes they exist in sufficient number)
static void fifo_pop( lua_State* L, keeper_fifo* fifo_, lua_Integer count_)
{
int const fifo_idx = lua_gettop( L); // ... fifo
int i;
// each iteration pushes a value on the stack!
STACK_GROW( L, count_ + 2);
// skip first item, we will push it last
for( i = 1; i < count_; ++ i)
{
int const at = (int)( fifo_->first + i);
// push item on the stack
lua_rawgeti( L, fifo_idx, at); // ... fifo val
// remove item from the fifo
lua_pushnil( L); // ... fifo val nil
lua_rawseti( L, fifo_idx, at); // ... fifo val
}
// now process first item
{
int const at = (int)( fifo_->first);
lua_rawgeti( L, fifo_idx, at); // ... fifo vals val
lua_pushnil( L); // ... fifo vals val nil
lua_rawseti( L, fifo_idx, at); // ... fifo vals val
lua_replace( L, fifo_idx); // ... vals
}
{
// avoid ever-growing indexes by resetting each time we detect the fifo is empty
lua_Integer const new_count = fifo_->count - count_;
fifo_->first = (new_count == 0) ? 1 : (fifo_->first + count_);
fifo_->count = new_count;
}
}
// in: linda_ud expected at *absolute* stack slot idx
// out: fifos[ud]
// crc64/we of string "FIFOS_KEY" generated at http://www.nitrxgen.net/hashgen/
static DECLARE_CONST_UNIQUE_KEY( FIFOS_KEY, 0xdce50bbc351cd465);
static void push_table( lua_State* L, int idx_)
{
STACK_GROW( L, 4);
STACK_CHECK( L, 0);
idx_ = lua_absindex( L, idx_);
REGISTRY_GET( L, FIFOS_KEY); // ud fifos
lua_pushvalue( L, idx_); // ud fifos ud
lua_rawget( L, -2); // ud fifos fifos[ud]
STACK_MID( L, 2);
if( lua_isnil( L, -1))
{
lua_pop( L, 1); // ud fifos
// add a new fifos table for this linda
lua_newtable( L); // ud fifos fifos[ud]
lua_pushvalue( L, idx_); // ud fifos fifos[ud] ud
lua_pushvalue( L, -2); // ud fifos fifos[ud] ud fifos[ud]
lua_rawset( L, -4); // ud fifos fifos[ud]
}
lua_remove( L, -2); // ud fifos[ud]
STACK_END( L, 1);
}
int keeper_push_linda_storage( Universe* U, lua_State* L, void* ptr_, ptrdiff_t magic_)
{
Keeper* const K = which_keeper( U->keepers, magic_);
lua_State* const KL = K ? K->L : NULL;
if( KL == NULL) return 0;
STACK_GROW( KL, 4);
STACK_CHECK( KL, 0);
REGISTRY_GET( KL, FIFOS_KEY); // fifos
lua_pushlightuserdata( KL, ptr_); // fifos ud
lua_rawget( KL, -2); // fifos storage
lua_remove( KL, -2); // storage
if( !lua_istable( KL, -1))
{
lua_pop( KL, 1); //
STACK_MID( KL, 0);
return 0;
}
// move data from keeper to destination state KEEPER MAIN
lua_pushnil( KL); // storage nil
STACK_GROW( L, 5);
STACK_CHECK( L, 0);
lua_newtable( L); // out
while( lua_next( KL, -2)) // storage key fifo
{
keeper_fifo* fifo = prepare_fifo_access( KL, -1); // storage key fifo
lua_pushvalue( KL, -2); // storage key fifo key
luaG_inter_move( U, KL, L, 1, eLM_FromKeeper); // storage key fifo // out key
STACK_MID( L, 2);
lua_newtable( L); // out key keyout
luaG_inter_move( U, KL, L, 1, eLM_FromKeeper); // storage key // out key keyout fifo
lua_pushinteger( L, fifo->first); // out key keyout fifo first
STACK_MID( L, 5);
lua_setfield( L, -3, "first"); // out key keyout fifo
lua_pushinteger( L, fifo->count); // out key keyout fifo count
STACK_MID( L, 5);
lua_setfield( L, -3, "count"); // out key keyout fifo
lua_pushinteger( L, fifo->limit); // out key keyout fifo limit
STACK_MID( L, 5);
lua_setfield( L, -3, "limit"); // out key keyout fifo
lua_setfield( L, -2, "fifo"); // out key keyout
lua_rawset( L, -3); // out
STACK_MID( L, 1);
}
STACK_END( L, 1);
lua_pop( KL, 1); //
STACK_END( KL, 0);
return 1;
}
// in: linda_ud
int keepercall_clear( lua_State* L)
{
STACK_GROW( L, 3);
STACK_CHECK( L, 0);
REGISTRY_GET( L, FIFOS_KEY); // ud fifos
lua_pushvalue( L, 1); // ud fifos ud
lua_pushnil( L); // ud fifos ud nil
lua_rawset( L, -3); // ud fifos
lua_pop( L, 1); // ud
STACK_END( L, 0);
return 0;
}
// in: linda_ud, key, ...
// out: true|false
int keepercall_send( lua_State* L)
{
keeper_fifo* fifo;
int n = lua_gettop( L) - 2;
push_table( L, 1); // ud key ... fifos
// get the fifo associated to this key in this linda, create it if it doesn't exist
lua_pushvalue( L, 2); // ud key ... fifos key
lua_rawget( L, -2); // ud key ... fifos fifo
if( lua_isnil( L, -1))
{
lua_pop( L, 1); // ud key ... fifos
fifo_new( L); // ud key ... fifos fifo
lua_pushvalue( L, 2); // ud key ... fifos fifo key
lua_pushvalue( L, -2); // ud key ... fifos fifo key fifo
lua_rawset( L, -4); // ud key ... fifos fifo
}
lua_remove( L, -2); // ud key ... fifo
fifo = (keeper_fifo*) lua_touserdata( L, -1);
if( fifo->limit >= 0 && fifo->count + n > fifo->limit)
{
lua_settop( L, 0); //
lua_pushboolean( L, 0); // false
}
else
{
fifo = prepare_fifo_access( L, -1);
lua_replace( L, 2); // ud fifo ...
fifo_push( L, fifo, n); // ud fifo
lua_settop( L, 0); //
lua_pushboolean( L, 1); // true
}
return 1;
}
// in: linda_ud, key [, key]?
// out: (key, val) or nothing
int keepercall_receive( lua_State* L)
{
int top = lua_gettop( L);
int i;
push_table( L, 1); // ud keys fifos
lua_replace( L, 1); // fifos keys
for( i = 2; i <= top; ++ i)
{
keeper_fifo* fifo;
lua_pushvalue( L, i); // fifos keys key[i]
lua_rawget( L, 1); // fifos keys fifo
fifo = prepare_fifo_access( L, -1); // fifos keys fifo
if( fifo != NULL && fifo->count > 0)
{
fifo_pop( L, fifo, 1); // fifos keys val
if( !lua_isnil( L, -1))
{
lua_replace( L, 1); // val keys
lua_settop( L, i); // val keys key[i]
if( i != 2)
{
lua_replace( L, 2); // val key keys
lua_settop( L, 2); // val key
}
lua_insert( L, 1); // key, val
return 2;
}
}
lua_settop( L, top); // data keys
}
// nothing to receive
return 0;
}
//in: linda_ud key mincount [maxcount]
int keepercall_receive_batched( lua_State* L)
{
lua_Integer const min_count = lua_tointeger( L, 3);
if( min_count > 0)
{
keeper_fifo* fifo;
lua_Integer const max_count = luaL_optinteger( L, 4, min_count);
lua_settop( L, 2); // ud key
lua_insert( L, 1); // key ud
push_table( L, 2); // key ud fifos
lua_remove( L, 2); // key fifos
lua_pushvalue( L, 1); // key fifos key
lua_rawget( L, 2); // key fifos fifo
lua_remove( L, 2); // key fifo
fifo = prepare_fifo_access( L, 2); // key fifo
if( fifo != NULL && fifo->count >= min_count)
{
fifo_pop( L, fifo, __min( max_count, fifo->count)); // key ...
}
else
{
lua_settop( L, 0);
}
return lua_gettop( L);
}
else
{
return 0;
}
}
// in: linda_ud key n
// out: true or nil
int keepercall_limit( lua_State* L)
{
keeper_fifo* fifo;
lua_Integer limit = lua_tointeger( L, 3);
push_table( L, 1); // ud key n fifos
lua_replace( L, 1); // fifos key n
lua_pop( L, 1); // fifos key
lua_pushvalue( L, -1); // fifos key key
lua_rawget( L, -3); // fifos key fifo|nil
fifo = (keeper_fifo*) lua_touserdata( L, -1);
if( fifo == NULL)
{ // fifos key nil
lua_pop( L, 1); // fifos key
fifo_new( L); // fifos key fifo
fifo = (keeper_fifo*) lua_touserdata( L, -1);
lua_rawset( L, -3); // fifos
}
// remove any clutter on the stack
lua_settop( L, 0);
// return true if we decide that blocked threads waiting to write on that key should be awakened
// this is the case if we detect the key was full but it is no longer the case
if(
((fifo->limit >= 0) && (fifo->count >= fifo->limit)) // the key was full if limited and count exceeded the previous limit
&& ((limit < 0) || (fifo->count < limit)) // the key is not full if unlimited or count is lower than the new limit
)
{
lua_pushboolean( L, 1);
}
// set the new limit
fifo->limit = limit;
// return 0 or 1 value
return lua_gettop( L);
}
//in: linda_ud key [[val] ...]
//out: true or nil
int keepercall_set( lua_State* L)
{
bool_t should_wake_writers = FALSE;
STACK_GROW( L, 6);
// retrieve fifos associated with the linda
push_table( L, 1); // ud key [val [, ...]] fifos
lua_replace( L, 1); // fifos key [val [, ...]]
// make sure we have a value on the stack
if( lua_gettop( L) == 2) // fifos key
{
keeper_fifo* fifo;
lua_pushvalue( L, -1); // fifos key key
lua_rawget( L, 1); // fifos key fifo|nil
// empty the fifo for the specified key: replace uservalue with a virgin table, reset counters, but leave limit unchanged!
fifo = (keeper_fifo*) lua_touserdata( L, -1);
if( fifo != NULL) // might be NULL if we set a nonexistent key to nil
{ // fifos key fifo
if( fifo->limit < 0) // fifo limit value is the default (unlimited): we can totally remove it
{
lua_pop( L, 1); // fifos key
lua_pushnil( L); // fifos key nil
lua_rawset( L, -3); // fifos
}
else
{
// we create room if the fifo was full but it is no longer the case
should_wake_writers = (fifo->limit > 0) && (fifo->count >= fifo->limit);
lua_remove( L, -2); // fifos fifo
lua_newtable( L); // fifos fifo {}
lua_setiuservalue( L, -2, CONTENTS_TABLE); // fifos fifo
fifo->first = 1;
fifo->count = 0;
}
}
}
else // set/replace contents stored at the specified key?
{
lua_Integer count = lua_gettop( L) - 2; // number of items we want to store
keeper_fifo* fifo; // fifos key [val [, ...]]
lua_pushvalue( L, 2); // fifos key [val [, ...]] key
lua_rawget( L, 1); // fifos key [val [, ...]] fifo|nil
fifo = (keeper_fifo*) lua_touserdata( L, -1);
if( fifo == NULL) // can be NULL if we store a value at a new key
{ // fifos key [val [, ...]] nil
// no need to wake writers in that case, because a writer can't wait on an inexistent key
lua_pop( L, 1); // fifos key [val [, ...]]
fifo_new( L); // fifos key [val [, ...]] fifo
lua_pushvalue( L, 2); // fifos key [val [, ...]] fifo key
lua_pushvalue( L, -2); // fifos key [val [, ...]] fifo key fifo
lua_rawset( L, 1); // fifos key [val [, ...]] fifo
}
else // the fifo exists, we just want to update its contents
{ // fifos key [val [, ...]] fifo
// we create room if the fifo was full but it is no longer the case
should_wake_writers = (fifo->limit > 0) && (fifo->count >= fifo->limit) && (count < fifo->limit);
// empty the fifo for the specified key: replace uservalue with a virgin table, reset counters, but leave limit unchanged!
lua_newtable( L); // fifos key [val [, ...]] fifo {}
lua_setiuservalue( L, -2, CONTENTS_TABLE); // fifos key [val [, ...]] fifo
fifo->first = 1;
fifo->count = 0;
}
fifo = prepare_fifo_access( L, -1);
// move the fifo below the values we want to store
lua_insert( L, 3); // fifos key fifo [val [, ...]]
fifo_push( L, fifo, count); // fifos key fifo
}
return should_wake_writers ? (lua_pushboolean( L, 1), 1) : 0;
}
// in: linda_ud key [count]
// out: at most <count> values
int keepercall_get( lua_State* L)
{
keeper_fifo* fifo;
lua_Integer count = 1;
if( lua_gettop( L) == 3) // ud key count
{
count = lua_tointeger( L, 3);
lua_pop( L, 1); // ud key
}
push_table( L, 1); // ud key fifos
lua_replace( L, 1); // fifos key
lua_rawget( L, 1); // fifos fifo
fifo = prepare_fifo_access( L, -1); // fifos fifo
if( fifo != NULL && fifo->count > 0)
{
lua_remove( L, 1); // fifo
count = __min( count, fifo->count);
// read <count> value off the fifo
fifo_peek( L, fifo, count); // fifo ...
return (int) count;
}
// no fifo was ever registered for this key, or it is empty
return 0;
}
// in: linda_ud [, key [, ...]]
int keepercall_count( lua_State* L)
{
push_table( L, 1); // ud keys fifos
switch( lua_gettop( L))
{
// no key is specified: return a table giving the count of all known keys
case 2: // ud fifos
lua_newtable( L); // ud fifos out
lua_replace( L, 1); // out fifos
lua_pushnil( L); // out fifos nil
while( lua_next( L, 2)) // out fifos key fifo
{
keeper_fifo* fifo = prepare_fifo_access( L, -1); // out fifos key fifo
lua_pop( L, 1); // out fifos key
lua_pushvalue( L, -1); // out fifos key key
lua_pushinteger( L, fifo->count); // out fifos key key count
lua_rawset( L, -5); // out fifos key
}
lua_pop( L, 1); // out
break;
// 1 key is specified: return its count
case 3: // ud key fifos
{
keeper_fifo* fifo;
lua_replace( L, 1); // fifos key
lua_rawget( L, -2); // fifos fifo|nil
if( lua_isnil( L, -1)) // the key is unknown
{ // fifos nil
lua_remove( L, -2); // nil
}
else // the key is known
{ // fifos fifo
fifo = prepare_fifo_access( L, -1); // fifos fifo
lua_pushinteger( L, fifo->count); // fifos fifo count
lua_replace( L, -3); // count fifo
lua_pop( L, 1); // count
}
}
break;
// a variable number of keys is specified: return a table of their counts
default: // ud keys fifos
lua_newtable( L); // ud keys fifos out
lua_replace( L, 1); // out keys fifos
// shifts all keys up in the stack. potentially slow if there are a lot of them, but then it should be bearable
lua_insert( L, 2); // out fifos keys
while( lua_gettop( L) > 2)
{
keeper_fifo* fifo;
lua_pushvalue( L, -1); // out fifos keys key
lua_rawget( L, 2); // out fifos keys fifo|nil
fifo = prepare_fifo_access( L, -1); // out fifos keys fifo|nil
lua_pop( L, 1); // out fifos keys
if( fifo != NULL) // the key is known
{
lua_pushinteger( L, fifo->count); // out fifos keys count
lua_rawset( L, 1); // out fifos keys
}
else // the key is unknown
{
lua_pop( L, 1); // out fifos keys
}
}
lua_pop( L, 1); // out
}
ASSERT_L( lua_gettop( L) == 1);
return 1;
}
//###################################################################################
// Keeper API, accessed from linda methods
//###################################################################################
/*---=== Keeper states ===---
*/
/*
* Pool of keeper states
*
* Access to keeper states is locked (only one OS thread at a time) so the
* bigger the pool, the less chances of unnecessary waits. Lindas map to the
* keepers randomly, by a hash.
*/
// called as __gc for the keepers array userdata
void close_keepers( Universe* U)
{
if( U->keepers != NULL)
{
int i;
int nbKeepers = U->keepers->nb_keepers;
// NOTE: imagine some keeper state N+1 currently holds a linda that uses another keeper N, and a _gc that will make use of it
// when keeper N+1 is closed, object is GCed, linda operation is called, which attempts to acquire keeper N, whose Lua state no longer exists
// in that case, the linda operation should do nothing. which means that these operations must check for keeper acquisition success
// which is early-outed with a U->keepers->nbKeepers null-check
U->keepers->nb_keepers = 0;
for( i = 0; i < nbKeepers; ++ i)
{
lua_State* K = U->keepers->keeper_array[i].L;
U->keepers->keeper_array[i].L = NULL;
if( K != NULL)
{
lua_close( K);
}
else
{
// detected partial init: destroy only the mutexes that got initialized properly
nbKeepers = i;
}
}
for( i = 0; i < nbKeepers; ++ i)
{
MUTEX_FREE( &U->keepers->keeper_array[i].keeper_cs);
}
// free the keeper bookkeeping structure
{
AllocatorDefinition* const allocD = &U->internal_allocator;
(void) allocD->allocF( allocD->allocUD, U->keepers, sizeof( Keepers) + (nbKeepers - 1) * sizeof( Keeper), 0);
U->keepers = NULL;
}
}
}
/*
* Initialize keeper states
*
* If there is a problem, returns NULL and pushes the error message on the stack
* else returns the keepers bookkeeping structure.
*
* Note: Any problems would be design flaws; the created Lua state is left
* unclosed, because it does not really matter. In production code, this
* function never fails.
* settings table is at position 1 on the stack
*/
void init_keepers( Universe* U, lua_State* L)
{
int i;
int nb_keepers;
STACK_CHECK( L, 0); // L K
lua_getfield( L, 1, "nb_keepers"); // nb_keepers
nb_keepers = (int) lua_tointeger( L, -1);
lua_pop( L, 1); //
if( nb_keepers < 1)
{
(void) luaL_error( L, "Bad number of keepers (%d)", nb_keepers);
}
// Keepers contains an array of 1 s_Keeper, adjust for the actual number of keeper states
{
size_t const bytes = sizeof( Keepers) + (nb_keepers - 1) * sizeof( Keeper);
{
AllocatorDefinition* const allocD = &U->internal_allocator;
U->keepers = (Keepers*) allocD->allocF( allocD->allocUD, NULL, 0, bytes);
}
if( U->keepers == NULL)
{
(void) luaL_error( L, "init_keepers() failed while creating keeper array; out of memory");
return;
}
memset( U->keepers, 0, bytes);
U->keepers->nb_keepers = nb_keepers;
}
for( i = 0; i < nb_keepers; ++ i) // keepersUD
{
// note that we will leak K if we raise an error later
lua_State* K = create_state( U, L);
if( K == NULL)
{
(void) luaL_error( L, "init_keepers() failed while creating keeper states; out of memory");
return;
}
U->keepers->keeper_array[i].L = K;
// we can trigger a GC from inside keeper_call(), where a keeper is acquired
// from there, GC can collect a linda, which would acquire the keeper again, and deadlock the thread.
// therefore, we need a recursive mutex.
MUTEX_RECURSIVE_INIT( &U->keepers->keeper_array[i].keeper_cs);
STACK_CHECK( K, 0);
// copy the universe pointer in the keeper itself
universe_store( K, U);
STACK_MID( K, 0);
// make sure 'package' is initialized in keeper states, so that we have require()
// this because this is needed when transferring deep userdata object
luaL_requiref( K, "package", luaopen_package, 1); // package
lua_pop( K, 1); //
STACK_MID( K, 0);
serialize_require( DEBUGSPEW_PARAM_COMMA( U) K);
STACK_MID( K, 0);
// copy package.path and package.cpath from the source state
lua_getglobal( L, "package"); // "..." keepersUD package
if( !lua_isnil( L, -1))
{
// when copying with mode eLM_ToKeeper, error message is pushed at the top of the stack, not raised immediately
if( luaG_inter_copy_package( U, L, K, -1, eLM_ToKeeper))
{
// if something went wrong, the error message is at the top of the stack
lua_remove( L, -2); // error_msg
(void) lua_error( L);
return;
}
}
lua_pop( L, 1); //
STACK_MID( L, 0);
// attempt to call on_state_create(), if we have one and it is a C function
// (only support a C function because we can't transfer executable Lua code in keepers)
// will raise an error in L in case of problem
call_on_state_create( U, K, L, eLM_ToKeeper);
// to see VM name in Decoda debugger
lua_pushfstring( K, "Keeper #%d", i + 1); // "Keeper #n"
lua_setglobal( K, "decoda_name"); //
// create the fifos table in the keeper state
REGISTRY_SET( K, FIFOS_KEY, lua_newtable( K));
STACK_END( K, 0);
}
STACK_END( L, 0);
}
// should be called only when inside a keeper_acquire/keeper_release pair (see linda_protected_call)
Keeper* which_keeper(Keepers* keepers_, ptrdiff_t magic_)
{
int const nbKeepers = keepers_->nb_keepers;
unsigned int i = (unsigned int)((magic_ >> KEEPER_MAGIC_SHIFT) % nbKeepers);
return &keepers_->keeper_array[i];
}
Keeper* keeper_acquire( Keepers* keepers_, ptrdiff_t magic_)
{
int const nbKeepers = keepers_->nb_keepers;
// can be 0 if this happens during main state shutdown (lanes is being GC'ed -> no keepers)
if( nbKeepers == 0)
{
return NULL;
}
else
{
/*
* Any hashing will do that maps pointers to 0..GNbKeepers-1
* consistently.
*
* Pointers are often aligned by 8 or so - ignore the low order bits
* have to cast to unsigned long to avoid compilation warnings about loss of data when converting pointer-to-integer
*/
unsigned int i = (unsigned int)((magic_ >> KEEPER_MAGIC_SHIFT) % nbKeepers);
Keeper* K = &keepers_->keeper_array[i];
MUTEX_LOCK( &K->keeper_cs);
//++ K->count;
return K;
}
}
void keeper_release( Keeper* K)
{
//-- K->count;
if( K) MUTEX_UNLOCK( &K->keeper_cs);
}
void keeper_toggle_nil_sentinels( lua_State* L, int val_i_, LookupMode const mode_)
{
int i, n = lua_gettop( L);
for( i = val_i_; i <= n; ++ i)
{
if( mode_ == eLM_ToKeeper)
{
if( lua_isnil( L, i))
{
push_unique_key( L, NIL_SENTINEL);
lua_replace( L, i);
}
}
else
{
if( equal_unique_key( L, i, NIL_SENTINEL))
{
lua_pushnil( L);
lua_replace( L, i);
}
}
}
}
/*
* Call a function ('func_name') in the keeper state, and pass on the returned
* values to 'L'.
*
* 'linda': deep Linda pointer (used only as a unique table key, first parameter)
* 'starting_index': first of the rest of parameters (none if 0)
*
* Returns: number of return values (pushed to 'L') or -1 in case of error
*/
int keeper_call( Universe* U, lua_State* K, keeper_api_t func_, lua_State* L, void* linda, uint_t starting_index)
{
int const args = starting_index ? (lua_gettop( L) - starting_index + 1) : 0;
int const Ktos = lua_gettop( K);
int retvals = -1;
STACK_GROW( K, 2);
PUSH_KEEPER_FUNC( K, func_);
lua_pushlightuserdata( K, linda);
if( (args == 0) || luaG_inter_copy( U, L, K, args, eLM_ToKeeper) == 0) // L->K
{
lua_call( K, 1 + args, LUA_MULTRET);
retvals = lua_gettop( K) - Ktos;
// note that this can raise a luaL_error while the keeper state (and its mutex) is acquired
// this may interrupt a lane, causing the destruction of the underlying OS thread
// after this, another lane making use of this keeper can get an error code from the mutex-locking function
// when attempting to grab the mutex again (WINVER <= 0x400 does this, but locks just fine, I don't know about pthread)
if( (retvals > 0) && luaG_inter_move( U, K, L, retvals, eLM_FromKeeper) != 0) // K->L
{
retvals = -1;
}
}
// whatever happens, restore the stack to where it was at the origin
lua_settop( K, Ktos);
return retvals;
}