path: root/comm/mailnews/db/mork/morkNode.cpp

/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*-  */
/* 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/. */

#ifndef _MDB_
#  include "mdb.h"
#endif

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

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

#ifndef _MORKPOOL_
#  include "morkPool.h"
#endif

#ifndef _MORKENV_
#  include "morkEnv.h"
#endif

#ifndef _MORKHANDLE_
#  include "morkHandle.h"
#endif

/*3456789_123456789_123456789_123456789_123456789_123456789_123456789_12345678*/

/* ===== ===== ===== ===== morkUsage ===== ===== ===== ===== */

static morkUsage morkUsage_gHeap;  // ensure EnsureReadyStaticUsage()
const morkUsage& morkUsage::kHeap = morkUsage_gHeap;

static morkUsage morkUsage_gStack;  // ensure EnsureReadyStaticUsage()
const morkUsage& morkUsage::kStack = morkUsage_gStack;

static morkUsage morkUsage_gMember;  // ensure EnsureReadyStaticUsage()
const morkUsage& morkUsage::kMember = morkUsage_gMember;

static morkUsage morkUsage_gGlobal;  // ensure EnsureReadyStaticUsage()
const morkUsage& morkUsage::kGlobal = morkUsage_gGlobal;

static morkUsage morkUsage_gPool;  // ensure EnsureReadyStaticUsage()
const morkUsage& morkUsage::kPool = morkUsage_gPool;

static morkUsage morkUsage_gNone;  // ensure EnsureReadyStaticUsage()
const morkUsage& morkUsage::kNone = morkUsage_gNone;

// This must be structured to allow for non-zero values in global variables
// just before static init time.  We can only safely check for whether a
// global has the address of some other global.  Please, do not initialize
// either of the variables below to zero, because this could break when a zero
// is assigned at static init time, but after EnsureReadyStaticUsage() runs.

static mork_u4 morkUsage_g_static_init_target;  // only address of this matters
static mork_u4* morkUsage_g_static_init_done;   // is address of target above?

#define morkUsage_do_static_init() \
  (morkUsage_g_static_init_done = &morkUsage_g_static_init_target)

#define morkUsage_need_static_init() \
  (morkUsage_g_static_init_done != &morkUsage_g_static_init_target)

/*static*/
void morkUsage::EnsureReadyStaticUsage() {
  if (morkUsage_need_static_init()) {
    morkUsage_do_static_init();

    morkUsage_gHeap.InitUsage(morkUsage_kHeap);
    morkUsage_gStack.InitUsage(morkUsage_kStack);
    morkUsage_gMember.InitUsage(morkUsage_kMember);
    morkUsage_gGlobal.InitUsage(morkUsage_kGlobal);
    morkUsage_gPool.InitUsage(morkUsage_kPool);
    morkUsage_gNone.InitUsage(morkUsage_kNone);
  }
}

/*static*/
const morkUsage& morkUsage::GetHeap()  // kHeap safe at static init time
{
  EnsureReadyStaticUsage();
  return morkUsage_gHeap;
}

/*static*/
const morkUsage& morkUsage::GetStack()  // kStack safe at static init time
{
  EnsureReadyStaticUsage();
  return morkUsage_gStack;
}

/*static*/
const morkUsage& morkUsage::GetMember()  // kMember safe at static init time
{
  EnsureReadyStaticUsage();
  return morkUsage_gMember;
}

/*static*/
const morkUsage& morkUsage::GetGlobal()  // kGlobal safe at static init time
{
  EnsureReadyStaticUsage();
  return morkUsage_gGlobal;
}

/*static*/
const morkUsage& morkUsage::GetPool()  // kPool safe at static init time
{
  EnsureReadyStaticUsage();
  return morkUsage_gPool;
}

/*static*/
const morkUsage& morkUsage::GetNone()  // kNone safe at static init time
{
  EnsureReadyStaticUsage();
  return morkUsage_gNone;
}

morkUsage::morkUsage() {
  if (morkUsage_need_static_init()) {
    morkUsage::EnsureReadyStaticUsage();
  }
}

morkUsage::morkUsage(mork_usage code) : mUsage_Code(code) {
  if (morkUsage_need_static_init()) {
    morkUsage::EnsureReadyStaticUsage();
  }
}

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/*static*/ void* morkNode::MakeNew(size_t inSize, nsIMdbHeap& ioHeap,
                                   morkEnv* ev) {
  void* node = 0;
  ioHeap.Alloc(ev->AsMdbEnv(), inSize, (void**)&node);
  if (!node) ev->OutOfMemoryError();

  return node;
}

/*public non-poly*/ void morkNode::ZapOld(morkEnv* ev, nsIMdbHeap* ioHeap) {
  if (this->IsNode()) {
    mork_usage usage = mNode_Usage;  // mNode_Usage before ~morkNode
    this->morkNode::~morkNode();     // first call polymorphic destructor
    if (ioHeap)                      // was this node heap allocated?
      ioHeap->Free(ev->AsMdbEnv(), this);
    else if (usage == morkUsage_kPool)  // mNode_Usage before ~morkNode
    {
      morkHandle* h = (morkHandle*)this;
      if (h->IsHandle() && h->GoodHandleTag()) {
        if (h->mHandle_Face) {
          if (ev->mEnv_HandlePool)
            ev->mEnv_HandlePool->ZapHandle(ev, h->mHandle_Face);
          else if (h->mHandle_Env && h->mHandle_Env->mEnv_HandlePool)
            h->mHandle_Env->mEnv_HandlePool->ZapHandle(ev, h->mHandle_Face);
        } else
          ev->NilPointerError();
      }
    }
  } else
    this->NonNodeError(ev);
}

/*public virtual*/ void morkNode::CloseMorkNode(
    morkEnv* ev)  // CloseNode() only if open
{
  if (this->IsOpenNode()) {
    this->MarkClosing();
    this->CloseNode(ev);
    this->MarkShut();
  }
}
NS_IMETHODIMP
morkNode::CloseMdbObject(nsIMdbEnv* mev) {
  return morkNode::CloseMdbObject((morkEnv*)mev);
}

nsresult morkNode::CloseMdbObject(morkEnv* ev) {
  // if only one ref, Handle_CutStrongRef will clean up better.
  if (mNode_Uses == 1)
    // XXX Casting mork_uses to nsresult
    return static_cast<nsresult>(CutStrongRef(ev));

  nsresult outErr = NS_OK;

  if (IsNode() && IsOpenNode()) {
    if (ev) {
      CloseMorkNode(ev);
      outErr = ev->AsErr();
    }
  }
  return outErr;
}

/*public virtual*/
morkNode::~morkNode()  // assert that CloseNode() executed earlier
{
  MORK_ASSERT(this->IsShutNode() ||
              IsDeadNode());  // sometimes we call destructor explicitly w/o
                              // freeing object.
  mNode_Access = morkAccess_kDead;
  mNode_Usage = morkUsage_kNone;
}

/*public virtual*/
// void CloseMorkNode(morkEnv* ev) = 0; // CloseNode() only if open
// CloseMorkNode() is the polymorphic close method called when uses==0,
// which must do NOTHING at all when IsOpenNode() is not true.  Otherwise,
// CloseMorkNode() should call a static close method specific to an object.
// Each such static close method should either call inherited static close
// methods, or else perform the consolidated effect of calling them, where
// subclasses should closely track any changes in base classes with care.

/*public non-poly*/
morkNode::morkNode(mork_usage inCode)
    : mNode_Heap(0),
      mNode_Base(morkBase_kNode),
      mNode_Derived(0)  // until subclass sets appropriately
      ,
      mNode_Access(morkAccess_kOpen),
      mNode_Usage(inCode),
      mNode_Mutable(morkAble_kEnabled),
      mNode_Load(morkLoad_kClean),
      mNode_Uses(1),
      mNode_Refs(1) {}

/*public non-poly*/
morkNode::morkNode(const morkUsage& inUsage, nsIMdbHeap* ioHeap)
    : mNode_Heap(ioHeap),
      mNode_Base(morkBase_kNode),
      mNode_Derived(0)  // until subclass sets appropriately
      ,
      mNode_Access(morkAccess_kOpen),
      mNode_Usage(inUsage.Code()),
      mNode_Mutable(morkAble_kEnabled),
      mNode_Load(morkLoad_kClean),
      mNode_Uses(1),
      mNode_Refs(1) {
  if (!ioHeap && mNode_Usage == morkUsage_kHeap) MORK_ASSERT(ioHeap);
}

/*public non-poly*/
morkNode::morkNode(morkEnv* ev, const morkUsage& inUsage, nsIMdbHeap* ioHeap)
    : mNode_Heap(ioHeap),
      mNode_Base(morkBase_kNode),
      mNode_Derived(0)  // until subclass sets appropriately
      ,
      mNode_Access(morkAccess_kOpen),
      mNode_Usage(inUsage.Code()),
      mNode_Mutable(morkAble_kEnabled),
      mNode_Load(morkLoad_kClean),
      mNode_Uses(1),
      mNode_Refs(1) {
  if (!ioHeap && mNode_Usage == morkUsage_kHeap) {
    this->NilHeapError(ev);
  }
}

/*protected non-poly*/ void morkNode::RefsUnderUsesWarning(morkEnv* ev) const {
  ev->NewError("mNode_Refs < mNode_Uses");
}

/*protected non-poly*/ void morkNode::NonNodeError(
    morkEnv* ev) const  // called when IsNode() is false
{
  ev->NewError("non-morkNode");
}

/*protected non-poly*/ void morkNode::NonOpenNodeError(
    morkEnv* ev) const  // when IsOpenNode() is false
{
  ev->NewError("non-open-morkNode");
}

/*protected non-poly*/ void morkNode::NonMutableNodeError(
    morkEnv* ev) const  // when IsMutable() is false
{
  ev->NewError("non-mutable-morkNode");
}

/*protected non-poly*/ void morkNode::NilHeapError(
    morkEnv* ev) const  // zero mNode_Heap w/ kHeap usage
{
  ev->NewError("nil mNode_Heap");
}

/*protected non-poly*/ void morkNode::RefsOverflowWarning(
    morkEnv* ev) const  // mNode_Refs overflow
{
  ev->NewWarning("mNode_Refs overflow");
}

/*protected non-poly*/ void morkNode::UsesOverflowWarning(
    morkEnv* ev) const  // mNode_Uses overflow
{
  ev->NewWarning("mNode_Uses overflow");
}

/*protected non-poly*/ void morkNode::RefsUnderflowWarning(
    morkEnv* ev) const  // mNode_Refs underflow
{
  ev->NewWarning("mNode_Refs underflow");
}

/*protected non-poly*/ void morkNode::UsesUnderflowWarning(
    morkEnv* ev) const  // mNode_Uses underflow
{
  ev->NewWarning("mNode_Uses underflow");
}

/*public non-poly*/ void morkNode::CloseNode(
    morkEnv* ev)  // called by CloseMorkNode();
{
  if (this->IsNode())
    this->MarkShut();
  else
    this->NonNodeError(ev);
}

extern void  // utility method very similar to morkNode::SlotStrongNode():
nsIMdbFile_SlotStrongFile(nsIMdbFile* self, morkEnv* ev, nsIMdbFile** ioSlot)
// If *ioSlot is non-nil, that file is released by CutStrongRef() and
// then zeroed out.  Then if self is non-nil, this is acquired by
// calling AddStrongRef(), and if the return value shows success,
// then self is put into slot *ioSlot.  Note self can be nil, so we take
// expression 'nsIMdbFile_SlotStrongFile(0, ev, &slot)'.
{
  nsIMdbFile* file = *ioSlot;
  if (self != file) {
    if (file) {
      *ioSlot = 0;
      NS_RELEASE(file);
    }
    if (self && ev->Good()) NS_ADDREF(*ioSlot = self);
  }
}

void  // utility method very similar to morkNode::SlotStrongNode():
nsIMdbHeap_SlotStrongHeap(nsIMdbHeap* self, morkEnv* ev, nsIMdbHeap** ioSlot)
// If *ioSlot is non-nil, that heap is released by CutStrongRef() and
// then zeroed out.  Then if self is non-nil, self is acquired by
// calling AddStrongRef(), and if the return value shows success,
// then self is put into slot *ioSlot.  Note self can be nil, so we
// permit expression 'nsIMdbHeap_SlotStrongHeap(0, ev, &slot)'.
{
  nsIMdbHeap* heap = *ioSlot;
  if (self != heap) {
    if (heap) *ioSlot = 0;

    if (self && ev->Good()) *ioSlot = self;
  }
}

/*public static*/ void morkNode::SlotStrongNode(morkNode* me, morkEnv* ev,
                                                morkNode** ioSlot)
// If *ioSlot is non-nil, that node is released by CutStrongRef() and
// then zeroed out.  Then if me is non-nil, this is acquired by
// calling AddStrongRef(), and if positive is returned to show success,
// then me is put into slot *ioSlot.  Note me can be nil, so we take
// expression 'morkNode::SlotStrongNode((morkNode*) 0, ev, &slot)'.
{
  morkNode* node = *ioSlot;
  if (me != node) {
    if (node) {
      // what if this nulls out the ev and causes asserts?
      // can we move this after the CutStrongRef()?
      *ioSlot = 0;
      node->CutStrongRef(ev);
    }
    if (me && me->AddStrongRef(ev)) *ioSlot = me;
  }
}

/*public static*/ void morkNode::SlotWeakNode(morkNode* me, morkEnv* ev,
                                              morkNode** ioSlot)
// If *ioSlot is non-nil, that node is released by CutWeakRef() and
// then zeroed out.  Then if me is non-nil, this is acquired by
// calling AddWeakRef(), and if positive is returned to show success,
// then me is put into slot *ioSlot.  Note me can be nil, so we
// expression 'morkNode::SlotWeakNode((morkNode*) 0, ev, &slot)'.
{
  morkNode* node = *ioSlot;
  if (me != node) {
    if (node) {
      *ioSlot = 0;
      node->CutWeakRef(ev);
    }
    if (me && me->AddWeakRef(ev)) *ioSlot = me;
  }
}

/*public non-poly*/ mork_uses morkNode::AddStrongRef(morkEnv* ev) {
  mork_uses outUses = 0;
  if (this->IsNode()) {
    mork_uses uses = mNode_Uses;
    mork_refs refs = mNode_Refs;
    if (refs < uses)  // need to fix broken refs/uses relation?
    {
      this->RefsUnderUsesWarning(ev);
      mNode_Refs = mNode_Uses = refs = uses;
    }
    if (refs < morkNode_kMaxRefCount)  // not too great?
    {
      mNode_Refs = ++refs;
      mNode_Uses = ++uses;
    } else
      this->RefsOverflowWarning(ev);

    outUses = uses;
  } else
    this->NonNodeError(ev);
  return outUses;
}

/*private non-poly*/ mork_bool morkNode::cut_use_count(
    morkEnv* ev)  // just one part of CutStrongRef()
{
  mork_bool didCut = morkBool_kFalse;
  if (this->IsNode()) {
    mork_uses uses = mNode_Uses;
    if (uses)  // not yet zero?
      mNode_Uses = --uses;
    else
      this->UsesUnderflowWarning(ev);

    didCut = morkBool_kTrue;
    if (!mNode_Uses)  // last use gone? time to close node?
    {
      if (this->IsOpenNode()) {
        if (!mNode_Refs)  // no outstanding reference?
        {
          this->RefsUnderflowWarning(ev);
          ++mNode_Refs;  // prevent potential crash during close
        }
        this->CloseMorkNode(ev);  // polymorphic self close
        // (Note CutNode() is not polymorphic -- so don't call that.)
      }
    }
  } else
    this->NonNodeError(ev);
  return didCut;
}

/*public non-poly*/ mork_uses morkNode::CutStrongRef(morkEnv* ev) {
  mork_refs outRefs = 0;
  if (this->IsNode()) {
    if (this->cut_use_count(ev)) outRefs = this->CutWeakRef(ev);
  } else
    this->NonNodeError(ev);

  return outRefs;
}

/*public non-poly*/ mork_refs morkNode::AddWeakRef(morkEnv* ev) {
  mork_refs outRefs = 0;
  if (this->IsNode()) {
    mork_refs refs = mNode_Refs;
    if (refs < morkNode_kMaxRefCount)  // not too great?
      mNode_Refs = ++refs;
    else
      this->RefsOverflowWarning(ev);

    outRefs = refs;
  } else
    this->NonNodeError(ev);

  return outRefs;
}

/*public non-poly*/ mork_refs morkNode::CutWeakRef(morkEnv* ev) {
  mork_refs outRefs = 0;
  if (this->IsNode()) {
    mork_uses uses = mNode_Uses;
    mork_refs refs = mNode_Refs;
    if (refs)  // not yet zero?
      mNode_Refs = --refs;
    else
      this->RefsUnderflowWarning(ev);

    if (refs < uses)  // need to fix broken refs/uses relation?
    {
      this->RefsUnderUsesWarning(ev);
      mNode_Refs = mNode_Uses = refs = uses;
    }

    outRefs = refs;
    if (!refs)  // last reference gone? time to destroy node?
      this->ZapOld(ev, mNode_Heap);  // self destroy, use this no longer
  } else
    this->NonNodeError(ev);

  return outRefs;
}

static const char morkNode_kBroken[] = "broken";

/*public non-poly*/ const char* morkNode::GetNodeAccessAsString()
    const  // e.g. "open", "shut", etc.
{
  const char* outString = morkNode_kBroken;
  switch (mNode_Access) {
    case morkAccess_kOpen:
      outString = "open";
      break;
    case morkAccess_kClosing:
      outString = "closing";
      break;
    case morkAccess_kShut:
      outString = "shut";
      break;
    case morkAccess_kDead:
      outString = "dead";
      break;
  }
  return outString;
}

/*public non-poly*/ const char* morkNode::GetNodeUsageAsString()
    const  // e.g. "heap", "stack", etc.
{
  const char* outString = morkNode_kBroken;
  switch (mNode_Usage) {
    case morkUsage_kHeap:
      outString = "heap";
      break;
    case morkUsage_kStack:
      outString = "stack";
      break;
    case morkUsage_kMember:
      outString = "member";
      break;
    case morkUsage_kGlobal:
      outString = "global";
      break;
    case morkUsage_kPool:
      outString = "pool";
      break;
    case morkUsage_kNone:
      outString = "none";
      break;
  }
  return outString;
}

// 456789_123456789_123456789_123456789_123456789_123456789_123456789_123456789