/* impl.c.root: ROOT IMPLEMENTATION
 *
 * $HopeName: MMsrc!root.c(trunk.26) $
 * Copyright (C) 1997 The Harlequin Group Limited.  All rights reserved.
 *
 * .scope: This is the implementation of the root datatype.
 * .design: For design, see design.mps.root and 
 * design.mps.root-interface
 */

#include "mpm.h"

SRCID(root, "$HopeName: MMsrc!root.c(trunk.26) $");


/* RootVarCheck -- check a Root union discriminator
 *
 * .rootvarcheck: Synchronize with impl.h.mpmtypes.rootvar
 */

Bool RootVarCheck(RootVar rootVar)
{
  AVER(rootVar == RootTABLE ||
       rootVar == RootTABLE_MASKED ||
       rootVar == RootFUN ||
       rootVar == RootFMT ||
       rootVar == RootREG);
  return TRUE;
}


/* RootModeCheck */

Bool RootModeCheck(RootMode mode)
{
  AVER((mode & (RootModeCONSTANT |
		RootModePROTECTABLE |
		RootModePROTECTABLE_INNER)) == mode);
  /* RootModePROTECTABLE_INNER implies RootModePROTECTABLE */
  AVER((mode & RootModePROTECTABLE_INNER) == 0 ||
       (mode & RootModePROTECTABLE));
  
  return TRUE;
}


/* RootCheck -- check the consistency of a root structure
 *
 * .rootcheck: Keep synchonized with impl.h.mpmst.root
 */

Bool RootCheck(Root root)
{
  CHECKS(Root, root);
  CHECKU(Arena, root->arena); 
  CHECKL(root->serial < root->arena->rootSerial);
  CHECKL(RingCheck(&root->arenaRing));
  CHECKL(RankCheck(root->rank));
  CHECKL(TraceSetCheck(root->grey));
  /* Don't need to check var here, because of the switch below */
  switch(root->var)
  {
    case RootTABLE:
    CHECKL(root->the.table.base != 0);
    CHECKL(root->the.table.base < root->the.table.limit);
    break;

    case RootTABLE_MASKED:
    CHECKL(root->the.tableMasked.base != 0);
    CHECKL(root->the.tableMasked.base < root->the.tableMasked.limit);
    /* Can't check anything about the mask. */
    break;

    case RootFUN:
    CHECKL(root->the.fun.scan != NULL);
    break;

    case RootREG:
    CHECKL(root->the.reg.scan != NULL);
    CHECKD(Thread, root->the.reg.thread);
    break;

    case RootFMT:
    CHECKL(root->the.fmt.scan != NULL);
    CHECKL(root->the.fmt.base != 0);
    CHECKL(root->the.fmt.base < root->the.fmt.limit);
    break;

    default:
    NOTREACHED;
  }
  CHECKL(RootModeCheck(root->mode));
  CHECKL(BoolCheck(root->protectable));
  if(root->protectable) {
    CHECKL(root->protBase != NULL);
    CHECKL(root->protLimit != NULL);
    CHECKL(root->protBase < root->protLimit);
    /* there is no AccessSetCheck */
  } else {
    CHECKL(root->protBase == NULL);
    CHECKL(root->protLimit == NULL);
    CHECKL(root->pm == (AccessSet)0);
  }
  return TRUE;
}


/* .create: create, RootCreateTable, RootCreateReg, RootCreateFmt, 
 *   RootCreateFun:
 * RootCreate* set up the appropriate union member, and call the generic
 * create function to do the actual creation 
 * 
 * See design.mps.root.init for initial value
 */

static Res rootCreate(Root *rootReturn, Arena arena,
                  Rank rank, RootMode mode, RootVar type,
                  union RootUnion *theUnionP)
{
  Root root;
  Res res;
  void *p;

  AVER(rootReturn != NULL);
  AVERT(Arena, arena);
  AVERT(Rank, rank);
  AVERT(RootVar, type);

  res = ArenaAlloc(&p, arena, sizeof(RootStruct));
  if(res != ResOK)
    return res;
  root = (Root)p; /* Avoid pun */

  root->arena = arena;
  root->rank = rank;
  root->var = type;
  root->the  = *theUnionP;
  root->grey = TraceSetEMPTY;
  root->summary = RefSetUNIV;
  root->mode = mode;
  root->pm = AccessSetEMPTY;
  root->protectable = FALSE;
  root->protBase = 0;
  root->protLimit = 0;

  /* See design.mps.arena.root-ring */
  RingInit(&root->arenaRing);

  root->serial = arena->rootSerial;
  ++arena->rootSerial;
  root->sig = RootSig;

  AVERT(Root, root);

  RingAppend(ArenaRootRing(arena), &root->arenaRing);

  *rootReturn = root;
  return ResOK;
}

static Res rootCreateProtectable(Root *rootReturn, Arena arena,
                                 Rank rank, RootMode mode,
				 RootVar var,
				 Addr base, Addr limit,
				 union RootUnion *theUnion)
{
  Res res;
  Root root;
  Ring node, next;

  res = rootCreate(&root, arena, rank, mode, var, theUnion);
  if(res != ResOK) {
    return res;
  }
  if(mode & RootModePROTECTABLE) {
    root->protectable = TRUE;
    if(mode & RootModePROTECTABLE_INNER) {
      root->protBase = AddrAlignUp(base, ArenaAlign(arena));
      root->protLimit = AddrAlignDown(limit, ArenaAlign(arena));
      if(!(root->protBase < root->protLimit)) {
        /* root had no inner pages */
        root->protectable = FALSE;
	root->mode &=~ (RootModePROTECTABLE|RootModePROTECTABLE_INNER);
      }
    } else {
      root->protBase = AddrAlignDown(base, ArenaAlign(arena));
      root->protLimit = AddrAlignUp(limit, ArenaAlign(arena));
    }
  }

  /* Check that this root doesn't intersect with any other root */
  RING_FOR(node, &arena->rootRing, next) {
    Root trial = RING_ELT(Root, arenaRing, node);
    if(trial != root) {
      /* (trial->protLimit <= root->protBase || */
      /*  root->protLimit <= trial->protBase) */
      /* is the "okay" state.  The negation of this is: */
      if(root->protBase < trial->protLimit &&
         trial->protBase < root->protLimit) {
	NOTREACHED;
	RootDestroy(root);
	return ResFAIL;
      }
    }
  }

  AVERT(Root, root);

  *rootReturn = root;
  return ResOK;
}

Res RootCreateTable(Root *rootReturn, Arena arena,
                    Rank rank, RootMode mode, Addr *base, Addr *limit)
{
  Res res;
  union RootUnion theUnion;

  AVER(rootReturn != NULL);
  AVERT(Arena, arena);
  AVER(RankCheck(rank));
  AVER(base != 0);
  AVER(base < limit);  

  theUnion.table.base = base;
  theUnion.table.limit = limit;

  res = rootCreateProtectable(rootReturn, arena, rank, mode,
                              RootTABLE, (Addr)base, (Addr)limit, &theUnion);
  return res;
}

Res RootCreateTableMasked(Root *rootReturn, Arena arena,
                          Rank rank, RootMode mode,
			  Addr *base, Addr *limit,
                          Word mask)
{
  union RootUnion theUnion;

  AVER(rootReturn != NULL);
  AVERT(Arena, arena);
  AVER(RankCheck(rank));
  AVER(base != 0);
  AVER(base < limit);
  /* Can't check anything about mask. */

  theUnion.tableMasked.base = base;
  theUnion.tableMasked.limit = limit;
  theUnion.tableMasked.mask = mask;

  return rootCreateProtectable(rootReturn, arena, rank, mode,
                               RootTABLE_MASKED,
			       (Addr)base, (Addr)limit, &theUnion);
}

Res RootCreateReg(Root *rootReturn, Arena arena,
                    Rank rank, Thread thread,
                    RootScanRegMethod scan, void *p, size_t s)
{
  union RootUnion theUnion;

  AVER(rootReturn != NULL);
  AVERT(Arena, arena);
  AVER(RankCheck(rank));
  AVERT(Thread, thread);
  AVER(scan != NULL);

  theUnion.reg.scan = scan;
  theUnion.reg.thread = thread;
  theUnion.reg.p = p;
  theUnion.reg.s = s;

  return rootCreate(rootReturn, arena, rank, (RootMode)0, RootREG, &theUnion);
}

Res RootCreateFmt(Root *rootReturn, Arena arena,
                  Rank rank, RootMode mode, FormatScanMethod scan,
                  Addr base, Addr limit)
{
  union RootUnion theUnion;

  AVER(rootReturn != NULL);
  AVERT(Arena, arena);
  AVER(RankCheck(rank));
  AVER(FUNCHECK(scan));
  AVER(base != 0);
  AVER(base < limit);

  theUnion.fmt.scan = scan;
  theUnion.fmt.base = base;
  theUnion.fmt.limit = limit;

  return rootCreateProtectable(rootReturn, arena, rank, mode,
                               RootFMT, base, limit, &theUnion);
}

Res RootCreateFun(Root *rootReturn, Arena arena,
                 Rank rank,
                 RootScanMethod scan,
                 void *p, size_t s)
{
  union RootUnion theUnion;

  AVER(rootReturn != NULL);
  AVERT(Arena, arena);
  AVER(RankCheck(rank));
  AVER(FUNCHECK(scan));

  theUnion.fun.scan = scan;
  theUnion.fun.p = p;
  theUnion.fun.s = s;

  return rootCreate(rootReturn, arena, rank, (RootMode)0, RootFUN, &theUnion);
}

void RootDestroy(Root root)
{
  Arena arena;

  AVERT(Root, root);

  arena = RootArena(root);

  AVERT(Arena, arena);

  RingRemove(&root->arenaRing);
  RingFinish(&root->arenaRing);

  root->sig = SigInvalid;

  ArenaFree(arena, root, sizeof(RootStruct));
}

Rank RootRank(Root root)
{
  AVERT(Root, root);
  return root->rank;
}

void RootGrey(Root root, Trace trace)
{
  AVERT(Root, root);
  AVERT(Trace, trace);
  
  root->grey = TraceSetAdd(root->grey, trace->ti);
}

static void rootSetSummary(Root root, RefSet summary)
{
  AVERT(Root, root);
  /* Can't check summary */
  if(root->protectable) {
    if(summary == RefSetUNIV) {
      root->summary = summary;
      root->pm &= ~AccessWRITE;
    } else {
      root->pm |= AccessWRITE;
      root->summary = summary;
    }
  } else
    AVER(root->summary == RefSetUNIV);
}

Res RootScan(ScanState ss, Root root)
{
  Res res;

  AVERT(Root, root);
  AVERT(ScanState, ss);
  AVER(root->rank == ss->rank);

  if(TraceSetInter(root->grey, ss->traces) == TraceSetEMPTY)
    return ResOK;

  AVER(ScanStateSummary(ss) == RefSetEMPTY);

  if(RootPM(root) != AccessSetEMPTY) {
    ProtSet(root->protBase, root->protLimit, AccessSetEMPTY);
  }

  switch(root->var) {
    case RootTABLE:
    res = TraceScanArea(ss, root->the.table.base, root->the.table.limit);
    if(res != ResOK)
      goto failScan;
    break;

    case RootTABLE_MASKED:
    res = TraceScanAreaMasked(ss,
                              root->the.tableMasked.base,
                              root->the.tableMasked.limit,
                              root->the.tableMasked.mask);
    if(res != ResOK)
      goto failScan;
    break;

    case RootFUN:
    res = (*root->the.fun.scan)(ss, root->the.fun.p, root->the.fun.s);
    if(res != ResOK)
      goto failScan;
    break;

    case RootREG:
    res = (*root->the.reg.scan)(ss, root->the.reg.thread,
                                root->the.reg.p, root->the.reg.s);
    if(res != ResOK)
      goto failScan;
    break;

    case RootFMT:
    res = (*root->the.fmt.scan)(ss, root->the.fmt.base,
                                root->the.fmt.limit);
    if(res != ResOK)
      goto failScan;
    break;

    default:
    NOTREACHED;
    res = ResUNIMPL;
    goto failScan;
  }

  AVER(res == ResOK);
  root->grey = TraceSetDiff(root->grey, ss->traces);
  rootSetSummary(root, ScanStateSummary(ss));
  EVENT_PWW(RootScan, root, ss->traces, ScanStateSummary(ss));

failScan:
  if(RootPM(root) != AccessSetEMPTY) {
    ProtSet(root->protBase, root->protLimit, RootPM(root));
  }

  return res;
}

/* Must be thread-safe.  See design.mps.interface.c.thread-safety. */
Arena RootArena(Root root)
{
  /* Can't AVER root as that would not be thread-safe */
  /* AVERT(Root, root); */
  return root->arena;
}

/* return TRUE if the addr is in a root (and the root is in *rootReturn) */
/* otherwise returns FALSE */
Bool RootOfAddr(Root *rootReturn, Arena arena, Addr addr)
{
  Ring node, next;

  AVER(rootReturn != NULL);
  AVERT(Arena, arena);
  /* addr is arbitrary and can't be checked */

  RING_FOR(node, &arena->rootRing, next) {
    Root root = RING_ELT(Root, arenaRing, node);

    if(root->protectable &&
       root->protBase <= addr && addr < root->protLimit) {
      *rootReturn = root;
      return TRUE;
    }
  }

  return FALSE;
}

void RootAccess(Root root, AccessSet mode)
{
  AVERT(Root, root);
  /* Can't AVERT mode. */
  AVER((root->pm & mode) != AccessSetEMPTY);
  AVER(mode == AccessWRITE); /* only write protection supported */

  rootSetSummary(root, RefSetUNIV);

  /* Access must now be allowed. */
  AVER((root->pm & mode) == AccessSetEMPTY);
  ProtSet(root->protBase, root->protLimit, root->pm);
}


AccessSet RootPM(Root root)
{
  AVERT(Root, root);
  return root->pm;
}


Res RootDescribe(Root root, mps_lib_FILE *stream)
{
  Res res;

  AVERT(Root, root);
  AVER(stream != NULL);

  res = WriteF(stream,
               "Root $P ($U) {\n", (WriteFP)root, (WriteFU)root->serial,
               "  arena $P ($U)\n", (WriteFP)root->arena, 
               (WriteFU)root->arena->serial,
               "  rank $U\n", (WriteFU)root->rank,
               "  grey $B\n", (WriteFB)root->grey,
               "  summary $B\n", (WriteFB)root->summary,
               NULL);
  if(res != ResOK) return res;

  switch(root->var) {
    case RootTABLE:
    res = WriteF(stream,
                 "  table base $A limit $A\n",
                 root->the.table.base,
                 root->the.table.limit,
                 NULL);
    if(res != ResOK) return res;
    break;

    case RootTABLE_MASKED:
    res = WriteF(stream,
                 "  table base $A limit $A mask $B\n",
                 root->the.tableMasked.base,
                 root->the.tableMasked.limit,
                 root->the.tableMasked.mask,
                 NULL);
    if(res != ResOK) return res;
    break;

    case RootFUN:
    res = WriteF(stream,
                 "  scan function $F\n", (WriteFF)root->the.fun.scan,
                 "  environment p $P s $W\n",
                 root->the.fun.p, (WriteFW)root->the.fun.s,
                 NULL);
    if(res != ResOK) return res;
    break;

    case RootREG:
    res = WriteF(stream,
                 "  thread $P\n", (WriteFP)root->the.reg.thread,
                 "  environment p $P", root->the.reg.p,
                 NULL);
    if(res != ResOK) return res;
    break;

    case RootFMT:
    res = WriteF(stream,
                 "  scan function $F\n", (WriteFF)root->the.fmt.scan,
                 "  format base $A limit $A\n",
                 root->the.fmt.base,
                 root->the.fmt.limit,
                 NULL);
    if(res != ResOK) return res;
    break;
           
    default:
    NOTREACHED;
  }

  res = WriteF(stream,
               "} Root $P ($U)\n", (WriteFP)root, (WriteFU)root->serial,
               NULL);
  if(res != ResOK) return res;

  return ResOK;
}