45bd14b392
Derivative of work by RobertGabrielJakabosky http://lua-users.org/wiki/EmergencyGarbageCollector I've only implemented the not enough memory part and expanded this idea to adding a mechanism to signal the OOM condition of the plugin buffer which allows us to only grab the playback buffer after garbage collection fails (SO THE MUSIC KEEPS PLAYING AS LONG AS POSSIBLE) Change-Id: I684fb98b540ffc01f7ba324ab5b761ceb59b9f9b
134 lines
4.1 KiB
C
134 lines
4.1 KiB
C
/*
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** $Id$
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** Garbage Collector
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** See Copyright Notice in lua.h
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*/
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#ifndef lgc_h
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#define lgc_h
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#include "lobject.h"
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/*
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** Possible states of the Garbage Collector
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*/
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#define GCSpause 0
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#define GCSpropagate 1
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#define GCSsweepstring 2
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#define GCSsweep 3
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#define GCSfinalize 4
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/*
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** some userful bit tricks
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*/
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#define resetbits(x,m) ((x) &= cast(lu_byte, ~(m)))
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#define setbits(x,m) ((x) |= (m))
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#define testbits(x,m) ((x) & (m))
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#define bitmask(b) (1<<(b))
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#define bit2mask(b1,b2) (bitmask(b1) | bitmask(b2))
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#define l_setbit(x,b) setbits(x, bitmask(b))
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#define resetbit(x,b) resetbits(x, bitmask(b))
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#define testbit(x,b) testbits(x, bitmask(b))
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#define set2bits(x,b1,b2) setbits(x, (bit2mask(b1, b2)))
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#define reset2bits(x,b1,b2) resetbits(x, (bit2mask(b1, b2)))
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#define test2bits(x,b1,b2) testbits(x, (bit2mask(b1, b2)))
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/*
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** Possible Garbage Collector flags.
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** Layout for bit use in 'gsflags' field in global_State structure.
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** bit 0 - Protect GC from recursive calls.
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** bit 1 - Don't try to shrink string table if EGC was called during a string table resize.
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*/
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#define GCFlagsNone 0
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#define GCBlockGCBit 0
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#define GCResizingStringsBit 1
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#define is_block_gc(L) testbit(G(L)->gcflags, GCBlockGCBit)
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#define set_block_gc(L) l_setbit(G(L)->gcflags, GCBlockGCBit)
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#define unset_block_gc(L) resetbit(G(L)->gcflags, GCBlockGCBit)
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#define is_resizing_strings_gc(L) testbit(G(L)->gcflags, GCResizingStringsBit)
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#define set_resizing_strings_gc(L) l_setbit(G(L)->gcflags, GCResizingStringsBit)
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#define unset_resizing_strings_gc(L) resetbit(G(L)->gcflags, GCResizingStringsBit)
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/*
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** Layout for bit use in `marked' field:
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** bit 0 - object is white (type 0)
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** bit 1 - object is white (type 1)
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** bit 2 - object is black
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** bit 3 - for thread: Don't resize thread's stack
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** bit 3 - for userdata: has been finalized
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** bit 3 - for tables: has weak keys
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** bit 4 - for tables: has weak values
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** bit 5 - object is fixed (should not be collected)
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** bit 6 - object is "super" fixed (only the main thread)
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*/
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#define WHITE0BIT 0
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#define WHITE1BIT 1
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#define BLACKBIT 2
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#define FIXEDSTACKBIT 3
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#define FINALIZEDBIT 3
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#define KEYWEAKBIT 3
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#define VALUEWEAKBIT 4
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#define FIXEDBIT 5
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#define SFIXEDBIT 6
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#define WHITEBITS bit2mask(WHITE0BIT, WHITE1BIT)
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#define iswhite(x) test2bits((x)->gch.marked, WHITE0BIT, WHITE1BIT)
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#define isblack(x) testbit((x)->gch.marked, BLACKBIT)
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#define isgray(x) (!isblack(x) && !iswhite(x))
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#define otherwhite(g) (g->currentwhite ^ WHITEBITS)
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#define isdead(g,v) ((v)->gch.marked & otherwhite(g) & WHITEBITS)
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#define changewhite(x) ((x)->gch.marked ^= WHITEBITS)
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#define gray2black(x) l_setbit((x)->gch.marked, BLACKBIT)
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#define valiswhite(x) (iscollectable(x) && iswhite(gcvalue(x)))
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#define luaC_white(g) cast(lu_byte, (g)->currentwhite & WHITEBITS)
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#define isfixedstack(x) testbit((x)->marked, FIXEDSTACKBIT)
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#define fixedstack(x) l_setbit((x)->marked, FIXEDSTACKBIT)
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#define unfixedstack(x) resetbit((x)->marked, FIXEDSTACKBIT)
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#define luaC_checkGC(L) { \
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condhardstacktests(luaD_reallocstack(L, L->stacksize - EXTRA_STACK - 1)); \
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if (G(L)->totalbytes >= G(L)->GCthreshold) \
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luaC_step(L); }
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#define luaC_barrier(L,p,v) { if (valiswhite(v) && isblack(obj2gco(p))) \
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luaC_barrierf(L,obj2gco(p),gcvalue(v)); }
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#define luaC_barriert(L,t,v) { if (valiswhite(v) && isblack(obj2gco(t))) \
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luaC_barrierback(L,t); }
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#define luaC_objbarrier(L,p,o) \
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{ if (iswhite(obj2gco(o)) && isblack(obj2gco(p))) \
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luaC_barrierf(L,obj2gco(p),obj2gco(o)); }
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#define luaC_objbarriert(L,t,o) \
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{ if (iswhite(obj2gco(o)) && isblack(obj2gco(t))) luaC_barrierback(L,t); }
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LUAI_FUNC size_t luaC_separateudata (lua_State *L, int all);
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LUAI_FUNC void luaC_callGCTM (lua_State *L);
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LUAI_FUNC void luaC_freeall (lua_State *L);
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LUAI_FUNC void luaC_step (lua_State *L);
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LUAI_FUNC void luaC_fullgc (lua_State *L);
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LUAI_FUNC int luaC_sweepstrgc (lua_State *L);
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LUAI_FUNC void luaC_marknew (lua_State *L, GCObject *o);
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LUAI_FUNC void luaC_link (lua_State *L, GCObject *o, lu_byte tt);
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LUAI_FUNC void luaC_linkupval (lua_State *L, UpVal *uv);
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LUAI_FUNC void luaC_barrierf (lua_State *L, GCObject *o, GCObject *v);
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LUAI_FUNC void luaC_barrierback (lua_State *L, Table *t);
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#endif
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