path: root/comm/mailnews/db/mork/morkProbeMap.h

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// This code is a port to NS Mork from public domain Mithril C++ sources.
// Note many code comments here come verbatim from cut-and-pasted Mithril.
// In many places, code is identical; Mithril versions stay public domain.
// Changes in porting are mainly class type and scalar type name changes.

#ifndef _MORKPROBEMAP_
#define _MORKPROBEMAP_ 1

#ifndef _MORK_
#  include "mork.h"
#endif

#ifndef _MORKNODE_
#  include "morkNode.h"
#endif

// 456789_123456789_123456789_123456789_123456789_123456789_123456789_123456789

class morkMapScratch {  // utility class used by map subclasses
 public:
  nsIMdbHeap* sMapScratch_Heap;  // cached sMap_Heap
  mork_count sMapScratch_Slots;  // cached sMap_Slots

  mork_u1* sMapScratch_Keys;  // cached sMap_Keys
  mork_u1* sMapScratch_Vals;  // cached sMap_Vals

 public:
  void halt_map_scratch(morkEnv* ev);
};

// 456789_123456789_123456789_123456789_123456789_123456789_123456789_123456789

#define morkDerived_kProbeMap 0x7072 /* ascii 'pr' */
#define morkProbeMap_kTag 0x70724D50 /* ascii 'prMP' */

#define morkProbeMap_kLazyClearOnAdd ((mork_u1)'c')

class morkProbeMap : public morkNode {
 protected:
  // public: // slots inherited from morkNode (meant to inform only)
  // nsIMdbHeap*       mNode_Heap;

  // mork_base      mNode_Base;     // must equal morkBase_kNode
  // mork_derived   mNode_Derived;  // depends on specific node subclass

  // mork_access    mNode_Access;   // kOpen, kClosing, kShut, or kDead
  // mork_usage     mNode_Usage;    // kHeap, kStack, kMember, kGlobal, kNone
  // mork_able      mNode_Mutable;  // can this node be modified?
  // mork_load      mNode_Load;     // is this node clean or dirty?

  // mork_uses      mNode_Uses;     // refcount for strong refs
  // mork_refs      mNode_Refs;     // refcount for strong refs + weak refs

 protected:
  // { begin morkMap slots
  nsIMdbHeap* sMap_Heap;  // strong ref to heap allocating all space

  mork_u1* sMap_Keys;
  mork_u1* sMap_Vals;

  mork_count sMap_Seed;  // change count of members or structure

  mork_count sMap_Slots;  // count of slots in the hash table
  mork_fill sMap_Fill;    // number of used slots in the hash table

  mork_size sMap_KeySize;  // size of each key (cannot be zero)
  mork_size sMap_ValSize;  // size of each val (zero allowed)

  mork_bool sMap_KeyIsIP;  // sMap_KeySize == sizeof(mork_ip)
  mork_bool sMap_ValIsIP;  // sMap_ValSize == sizeof(mork_ip)
  mork_u1 sMap_Pad[2];     // for u4 alignment
  // } end morkMap slots

  friend class morkProbeMapIter;  // for access to protected slots

 public:  // getters
  mork_count MapSeed() const { return sMap_Seed; }

  mork_count MapSlots() const { return sMap_Slots; }
  mork_fill MapFill() const { return sMap_Fill; }

  mork_size MapKeySize() const { return sMap_KeySize; }
  mork_size MapValSize() const { return sMap_ValSize; }

  mork_bool MapKeyIsIP() const { return sMap_KeyIsIP; }
  mork_bool MapValIsIP() const { return sMap_ValIsIP; }

 protected:  // slots
  // { begin morkProbeMap slots

  mork_fill sProbeMap_MaxFill;  // max sMap_Fill before map must grow

  mork_u1 sProbeMap_LazyClearOnAdd;    // true if kLazyClearOnAdd
  mork_bool sProbeMap_ZeroIsClearKey;  // zero is adequate to clear keys
  mork_u1 sProbeMap_Pad[2];            // for u4 alignment

  mork_u4 sProbeMap_Tag;

  // } end morkProbeMap slots

 public:  // lazy clear on add
  mork_bool need_lazy_init() const {
    return sProbeMap_LazyClearOnAdd == morkProbeMap_kLazyClearOnAdd;
  }

 public:  // typing
  mork_bool GoodProbeMap() const { return sProbeMap_Tag == morkProbeMap_kTag; }

 protected:  // utilities
  void* clear_alloc(morkEnv* ev, mork_size inSize);

  mork_u1* map_new_vals(morkEnv* ev, mork_num inSlots);
  mork_u1* map_new_keys(morkEnv* ev, mork_num inSlots);

  void clear_probe_map(morkEnv* ev, nsIMdbHeap* ioMapHeap);
  void init_probe_map(morkEnv* ev, mork_size inSlots);
  void probe_map_lazy_init(morkEnv* ev);

  mork_bool new_slots(morkEnv* ev, morkMapScratch* old, mork_num inSlots);

  mork_test find_key_pos(morkEnv* ev, const void* inAppKey, mork_u4 inHash,
                         mork_pos* outPos) const;

  void put_probe_kv(morkEnv* ev, const void* inAppKey, const void* inAppVal,
                    mork_pos inPos);
  void get_probe_kv(morkEnv* ev, void* outAppKey, void* outAppVal,
                    mork_pos inPos) const;

  mork_bool grow_probe_map(morkEnv* ev);
  void rehash_old_map(morkEnv* ev, morkMapScratch* ioScratch);
  void revert_map(morkEnv* ev, morkMapScratch* ioScratch);

 public:  // errors
  void ProbeMapBadTagError(morkEnv* ev) const;
  void WrapWithNoVoidSlotError(morkEnv* ev) const;
  void GrowFailsMaxFillError(morkEnv* ev) const;
  void MapKeyIsNotIPError(morkEnv* ev) const;
  void MapValIsNotIPError(morkEnv* ev) const;

  void MapNilKeysError(morkEnv* ev);
  void MapZeroKeySizeError(morkEnv* ev);

  void MapSeedOutOfSyncError(morkEnv* ev);
  void MapFillUnderflowWarning(morkEnv* ev);

  static void ProbeMapCutError(morkEnv* ev);

  // { ===== begin morkMap methods =====
 public:
  virtual mork_test  // hit(a,b) implies hash(a) == hash(b)
  MapTest(morkEnv* ev, const void* inMapKey, const void* inAppKey) const;
  // Note inMapKey is always a key already stored in the map, while inAppKey
  //   is always a method argument parameter from a client method call.
  //   This matters the most in morkProbeMap subclasses, which have the
  //   responsibility of putting 'app' keys into slots for 'map' keys, and
  //   the bit pattern representation might be different in such cases.
  // morkTest_kHit means that inMapKey equals inAppKey (and this had better
  //   also imply that hash(inMapKey) == hash(inAppKey)).
  // morkTest_kMiss means that inMapKey does NOT equal inAppKey (but this
  //   implies nothing at all about hash(inMapKey) and hash(inAppKey)).
  // morkTest_kVoid means that inMapKey is not a valid key bit pattern,
  //   which means that key slot in the map is not being used.  Note that
  //   kVoid is only expected as a return value in morkProbeMap subclasses,
  //   because morkProbeMap must ask whether a key slot is used or not.
  //   morkChainMap however, always knows when a key slot is used, so only
  //   key slots expected to have valid bit patterns will be presented to
  //   the MapTest() methods for morkChainMap subclasses.
  //
  // NOTE: it is very important that subclasses correctly return the value
  // morkTest_kVoid whenever the slot for inMapKey contains a bit pattern
  // that means the slot is not being used, because this is the only way a
  // probe map can terminate an unsuccessful search for a key in the map.

  virtual mork_u4  // hit(a,b) implies hash(a) == hash(b)
  MapHash(morkEnv* ev, const void* inAppKey) const;

  virtual mork_bool MapAtPut(morkEnv* ev, const void* inAppKey,
                             const void* inAppVal, void* outAppKey,
                             void* outAppVal);

  virtual mork_bool MapAt(morkEnv* ev, const void* inAppKey, void* outAppKey,
                          void* outAppVal);

  virtual mork_num MapCutAll(morkEnv* ev);
  // } ===== end morkMap methods =====

  // { ===== begin morkProbeMap methods =====
 public:
  virtual mork_u4 ProbeMapHashMapKey(morkEnv* ev, const void* inMapKey) const;
  // ProbeMapHashMapKey() does logically the same thing as MapHash(), and
  // the default implementation actually calls virtual MapHash().  However,
  // Subclasses must override this method whenever the formats of keys in
  // the map differ from app keys outside the map, because MapHash() only
  // works on keys in 'app' format, while ProbeMapHashMapKey() only works
  // on keys in 'map' format.  This method is called in order to rehash all
  // map keys when a map is grown, and this causes all old map members to
  // move into new slot locations.
  //
  // Note it is absolutely imperative that a hash for a key in 'map' format
  // be exactly the same the hash of the same key in 'app' format, or else
  // maps will seem corrupt later when keys in 'app' format cannot be found.

  virtual mork_bool ProbeMapIsKeyNil(morkEnv* ev, void* ioMapKey);
  // ProbeMapIsKeyNil() must say whether the representation of logical 'nil'
  // is currently found inside the key at ioMapKey, for a key found within
  // the map.  The the map iterator uses this method to find map keys that
  // are actually being used for valid map associations; otherwise the
  // iterator cannot determine which map slots actually denote used keys.
  // The default method version returns true if all the bits equal zero.

  virtual void ProbeMapClearKey(
      morkEnv* ev,  // put 'nil' into all keys inside map
      void* ioMapKey, mork_count inKeyCount);  // array of keys inside map
  // ProbeMapClearKey() must put some representation of logical 'nil' into
  // every key slot in the map, such that MapTest() will later recognize
  // that this bit pattern shows each key slot is not actually being used.
  //
  // This method is typically called whenever the map is either created or
  // grown into a larger size, where ioMapKey is a pointer to an array of
  // inKeyCount keys, where each key is this->MapKeySize() bytes in size.
  // Note that keys are assumed immediately adjacent with no padding, so
  // if any alignment requirements must be met, then subclasses should have
  // already accounted for this when specifying a key size in the map.
  //
  // Since this method will be called when a map is being grown in size,
  // nothing should be assumed about the state slots of the map, since the
  // ioMapKey array might not yet live in sMap_Keys, and the array length
  // inKeyCount might not yet live in sMap_Slots.  However, the value kept
  // in sMap_KeySize never changes, so this->MapKeySize() is always correct.

  virtual void ProbeMapPushIn(morkEnv* ev,  // move (key,val) into the map
                              const void* inAppKey,
                              const void* inAppVal,  // (key,val) outside map
                              void* outMapKey,
                              void* outMapVal);  // (key,val) inside map
  // This method actually puts keys and vals in the map in suitable format.
  //
  // ProbeMapPushIn() must copy a caller key and value in 'app' format
  // into the map slots provided, which are in 'map' format.  When the
  // 'app' and 'map' formats are identical, then this is just a bitwise
  // copy of this->MapKeySize() key bytes and this->MapValSize() val bytes,
  // and this is exactly what the default implementation performs.  However,
  // if 'app' and 'map' formats are different, and MapTest() depends on this
  // difference in format, then subclasses must override this method to do
  // whatever is necessary to store the input app key in output map format.
  //
  // Do NOT write more than this->MapKeySize() bytes of a map key, or more
  // than this->MapValSize() bytes of a map val, or corruption might ensue.
  //
  // The inAppKey and inAppVal parameters are the same ones passed into a
  // call to MapAtPut(), and the outMapKey and outMapVal parameters are ones
  // determined by how the map currently positions key inAppKey in the map.
  //
  // Note any key or val parameter can be a null pointer, in which case
  // this method must do nothing with those parameters.  In particular, do
  // no key move at all when either inAppKey or outMapKey is nil, and do
  // no val move at all when either inAppVal or outMapVal is nil.  Note that
  // outMapVal should always be nil when this->MapValSize() is nil.

  virtual void ProbeMapPullOut(morkEnv* ev,  // move (key,val) out from the map
                               const void* inMapKey,
                               const void* inMapVal,  // (key,val) inside map
                               void* outAppKey,
                               void* outAppVal) const;  // (key,val) outside map
  // This method actually gets keys and vals from the map in suitable format.
  //
  // ProbeMapPullOut() must copy a key and val in 'map' format into the
  // caller key and val slots provided, which are in 'app' format.  When the
  // 'app' and 'map' formats are identical, then this is just a bitwise
  // copy of this->MapKeySize() key bytes and this->MapValSize() val bytes,
  // and this is exactly what the default implementation performs.  However,
  // if 'app' and 'map' formats are different, and MapTest() depends on this
  // difference in format, then subclasses must override this method to do
  // whatever is necessary to store the input map key in output app format.
  //
  // The outAppKey and outAppVal parameters are the same ones passed into a
  // call to either MapAtPut() or MapAt(), while inMapKey and inMapVal are
  // determined by how the map currently positions the target key in the map.
  //
  // Note any key or val parameter can be a null pointer, in which case
  // this method must do nothing with those parameters.  In particular, do
  // no key move at all when either inMapKey or outAppKey is nil, and do
  // no val move at all when either inMapVal or outAppVal is nil.  Note that
  // inMapVal should always be nil when this->MapValSize() is nil.

  // } ===== end morkProbeMap methods =====

  // { ===== begin morkNode interface =====
 public:  // morkNode virtual methods
  virtual void CloseMorkNode(
      morkEnv* ev) override;  // CloseProbeMap() only if open
  virtual ~morkProbeMap();    // assert that CloseProbeMap() executed earlier

 public:  // morkProbeMap construction & destruction
  morkProbeMap(morkEnv* ev, const morkUsage& inUsage, nsIMdbHeap* ioNodeHeap,
               mork_size inKeySize, mork_size inValSize, nsIMdbHeap* ioMapHeap,
               mork_size inSlots, mork_bool inZeroIsClearKey);

  void CloseProbeMap(morkEnv* ev);  // called by

 public:  // dynamic type identification
  mork_bool IsProbeMap() const {
    return IsNode() && mNode_Derived == morkDerived_kProbeMap;
  }
  // } ===== end morkNode methods =====

 public:  // typesafe refcounting inlines calling inherited morkNode methods
  static void SlotWeakMap(morkMap* me, morkEnv* ev, morkMap** ioSlot) {
    morkNode::SlotWeakNode((morkNode*)me, ev, (morkNode**)ioSlot);
  }

  static void SlotStrongMap(morkMap* me, morkEnv* ev, morkMap** ioSlot) {
    morkNode::SlotStrongNode((morkNode*)me, ev, (morkNode**)ioSlot);
  }
};

/*============================================================================*/
/* morkProbeMapIter */

#define morkProbeMapIter_kBeforeIx ((mork_i4)-1) /* before first member */
#define morkProbeMapIter_kAfterIx ((mork_i4)-2)  /* after last member */

class morkProbeMapIter {
 protected:
  morkProbeMap* sProbeMapIter_Map;  // nonref
  mork_num sProbeMapIter_Seed;      // iter's cached copy of map's seed

  mork_i4 sProbeMapIter_HereIx;

  mork_change sProbeMapIter_Change;  // morkMapIter API simulation dummy
  mork_u1 sProbeMapIter_Pad[3];      // for u4 alignment

 public:
  morkProbeMapIter(morkEnv* ev, morkProbeMap* ioMap);
  void CloseMapIter(morkEnv* ev);

  morkProbeMapIter();  // zero most slots; caller must call InitProbeMapIter()

 protected:  // protected so subclasses must provide suitable typesafe inlines:
  void InitProbeMapIter(morkEnv* ev, morkProbeMap* ioMap);

  void InitMapIter(morkEnv* ev,
                   morkProbeMap* ioMap)  // morkMapIter compatibility
  {
    this->InitProbeMapIter(ev, ioMap);
  }

  mork_bool IterFirst(morkEnv* ev, void* outKey, void* outVal);
  mork_bool IterNext(morkEnv* ev, void* outKey, void* outVal);
  mork_bool IterHere(morkEnv* ev, void* outKey, void* outVal);

  // NOTE: the following methods ONLY work for sMap_ValIsIP pointer values.
  // (Note the implied assumption that zero is never a good value pattern.)

  void* IterFirstVal(morkEnv* ev, void* outKey);
  // equivalent to { void* v=0; this->IterFirst(ev, outKey, &v); return v; }

  void* IterNextVal(morkEnv* ev, void* outKey);
  // equivalent to { void* v=0; this->IterNext(ev, outKey, &v); return v; }

  void* IterHereVal(morkEnv* ev, void* outKey);
  // equivalent to { void* v=0; this->IterHere(ev, outKey, &v); return v; }

  // NOTE: the following methods ONLY work for sMap_KeyIsIP pointer values.
  // (Note the implied assumption that zero is never a good key pattern.)

  void* IterFirstKey(morkEnv* ev);
  // equivalent to { void* k=0; this->IterFirst(ev, &k, 0); return k; }

  void* IterNextKey(morkEnv* ev);
  // equivalent to { void* k=0; this->IterNext(ev, &k, 0); return k; }

  void* IterHereKey(morkEnv* ev);
  // equivalent to { void* k=0; this->IterHere(ev, &k, 0); return k; }

 public:  // simulation of the morkMapIter API for morkMap compatibility:
  mork_change* First(morkEnv* ev, void* outKey, void* outVal);
  mork_change* Next(morkEnv* ev, void* outKey, void* outVal);
  mork_change* Here(morkEnv* ev, void* outKey, void* outVal);

  mork_change* CutHere(morkEnv* ev, void* outKey, void* outVal);
};

// 456789_123456789_123456789_123456789_123456789_123456789_123456789_123456789

#endif /* _MORKPROBEMAP_ */