/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
 * vim: set ts=8 sts=4 et sw=4 tw=99:
 * This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

/*
 * JS engine garbage collector API.
 */

#ifndef gc_GC_h
#define gc_GC_h

#include "jsapi.h"

#include "gc/AllocKind.h"
#include "gc/GCEnum.h"
#include "js/TraceKind.h"

class JSExternalString;
class JSFatInlineString;
class JSTracer;

namespace js {

class AccessorShape;
class FatInlineAtom;
class FreeOp;
class NormalAtom;

class Nursery;

namespace gc {

class Arena;
struct Chunk;
struct Cell;

/*
 * Map from C++ type to alloc kind for non-object types. JSObject does not have
 * a 1:1 mapping, so must use Arena::thingSize.
 *
 * The AllocKind is available as MapTypeToFinalizeKind<SomeType>::kind.
 */
template <typename T>
struct MapTypeToFinalizeKind {};
#define EXPAND_MAPTYPETOFINALIZEKIND(allocKind, traceKind, type, sizedType, \
                                     bgFinal, nursery)                      \
  template <>                                                               \
  struct MapTypeToFinalizeKind<type> {                                      \
    static const AllocKind kind = AllocKind::allocKind;                     \
  };
FOR_EACH_NONOBJECT_ALLOCKIND(EXPAND_MAPTYPETOFINALIZEKIND)
#undef EXPAND_MAPTYPETOFINALIZEKIND

} /* namespace gc */

extern void TraceRuntime(JSTracer* trc);

extern void ReleaseAllJITCode(FreeOp* op);

extern void PrepareForDebugGC(JSRuntime* rt);

/* Functions for managing cross compartment gray pointers. */

extern void NotifyGCNukeWrapper(JSObject* o);

extern unsigned NotifyGCPreSwap(JSObject* a, JSObject* b);

extern void NotifyGCPostSwap(JSObject* a, JSObject* b, unsigned preResult);

typedef void (*IterateChunkCallback)(JSRuntime* rt, void* data,
                                     gc::Chunk* chunk);
typedef void (*IterateZoneCallback)(JSRuntime* rt, void* data, JS::Zone* zone);
typedef void (*IterateArenaCallback)(JSRuntime* rt, void* data,
                                     gc::Arena* arena, JS::TraceKind traceKind,
                                     size_t thingSize);
typedef void (*IterateCellCallback)(JSRuntime* rt, void* data, void* thing,
                                    JS::TraceKind traceKind, size_t thingSize);

/*
 * This function calls |zoneCallback| on every zone, |compartmentCallback| on
 * every compartment, |arenaCallback| on every in-use arena, and |cellCallback|
 * on every in-use cell in the GC heap.
 *
 * Note that no read barrier is triggered on the cells passed to cellCallback,
 * so no these pointers must not escape the callback.
 */
extern void IterateHeapUnbarriered(
    JSContext* cx, void* data, IterateZoneCallback zoneCallback,
    JSIterateCompartmentCallback compartmentCallback,
    IterateArenaCallback arenaCallback, IterateCellCallback cellCallback);

/*
 * This function is like IterateZonesCompartmentsArenasCells, but does it for a
 * single zone.
 */
extern void IterateHeapUnbarrieredForZone(
    JSContext* cx, JS::Zone* zone, void* data, IterateZoneCallback zoneCallback,
    JSIterateCompartmentCallback compartmentCallback,
    IterateArenaCallback arenaCallback, IterateCellCallback cellCallback);

/*
 * Invoke chunkCallback on every in-use chunk.
 */
extern void IterateChunks(JSContext* cx, void* data,
                          IterateChunkCallback chunkCallback);

typedef void (*IterateScriptCallback)(JSRuntime* rt, void* data,
                                      JSScript* script);

/*
 * Invoke scriptCallback on every in-use script for
 * the given compartment or for all compartments if it is null.
 */
extern void IterateScripts(JSContext* cx, JSCompartment* compartment,
                           void* data, IterateScriptCallback scriptCallback);

JSCompartment* NewCompartment(JSContext* cx, JSPrincipals* principals,
                              const JS::CompartmentOptions& options);

namespace gc {

void FinishGC(JSContext* cx);

/*
 * Merge all contents of source into target. This can only be used if source is
 * the only compartment in its zone.
 */
void MergeCompartments(JSCompartment* source, JSCompartment* target);

enum VerifierType { PreBarrierVerifier };

#ifdef JS_GC_ZEAL

extern const char* ZealModeHelpText;

/* Check that write barriers have been used correctly. See gc/Verifier.cpp. */
void VerifyBarriers(JSRuntime* rt, VerifierType type);

void MaybeVerifyBarriers(JSContext* cx, bool always = false);

void DumpArenaInfo();

#else

static inline void VerifyBarriers(JSRuntime* rt, VerifierType type) {}

static inline void MaybeVerifyBarriers(JSContext* cx, bool always = false) {}

#endif

/*
 * Instances of this class set the |JSRuntime::suppressGC| flag for the duration
 * that they are live. Use of this class is highly discouraged. Please carefully
 * read the comment in vm/Runtime.h above |suppressGC| and take all appropriate
 * precautions before instantiating this class.
 */
class MOZ_RAII JS_HAZ_GC_SUPPRESSED AutoSuppressGC {
  int32_t& suppressGC_;

 public:
  explicit AutoSuppressGC(JSContext* cx);

  ~AutoSuppressGC() { suppressGC_--; }
};

const char* StateName(State state);

} /* namespace gc */

/* Use this to avoid assertions when manipulating the wrapper map. */
class MOZ_RAII AutoDisableProxyCheck {
 public:
#ifdef DEBUG
  AutoDisableProxyCheck();
  ~AutoDisableProxyCheck();
#else
  AutoDisableProxyCheck() {}
#endif
};

struct MOZ_RAII AutoDisableCompactingGC {
  explicit AutoDisableCompactingGC(JSContext* cx);
  ~AutoDisableCompactingGC();

 private:
  JSContext* cx;
};

// This is the same as IsInsideNursery, but not inlined.
bool UninlinedIsInsideNursery(const gc::Cell* cell);

} /* namespace js */

#endif /* gc_GC_h */
