fixup! New API function mps_pool_walk.

code/format.c

@@ -40,8 +40,7 @@ Bool FormatCheck(Format format)
 
 /* FormatNo methods -- default values for format keyword arguments */
 
-static mps_res_t FormatNoScan(mps_ss_t mps_ss, mps_addr_t base,
-                              mps_addr_t limit)
+mps_res_t FormatNoScan(mps_ss_t mps_ss, mps_addr_t base, mps_addr_t limit)
 {
     UNUSED(mps_ss);
     UNUSED(base);

code/mpm.h

@@ -811,6 +811,7 @@ extern Res FormatCreate(Format *formatReturn, Arena arena, ArgList args);
 extern void FormatDestroy(Format format);
 extern Arena FormatArena(Format format);
 extern Res FormatDescribe(Format format, mps_lib_FILE *stream, Count depth);
+extern mps_res_t FormatNoScan(mps_ss_t mps_ss, mps_addr_t base, mps_addr_t limit);
 
 
 /* Reference Interface -- see <code/ref.c> */

code/mpmst.h

@@ -402,8 +402,9 @@ typedef struct ScanStateStruct {
   Sig sig;                      /* <design/sig> */
   struct mps_ss_s ss_s;         /* .ss <http://bash.org/?400459> */
   Arena arena;                  /* owning arena */
-  mps_area_scan_t formatScan;   /* formatted area scanning function */
-  void *formatScanClosure;      /* closure argument for .formatScan */
+  mps_fmt_scan_t formatScan;    /* callback for scanning formatted objects */
+  mps_area_scan_t areaScan;     /* ditto via the area scanning interface */
+  void *areaScanClosure;        /* closure argument for areaScan */
   SegFixMethod fix;             /* third stage fix function */
   void *fixClosure;             /* see .ss.fix-closure */
   TraceSet traces;              /* traces to scan for */

code/trace.c

@@ -38,7 +38,8 @@ Bool ScanStateCheck(ScanState ss)
 
   CHECKS(ScanState, ss);
   CHECKL(FUNCHECK(ss->formatScan));
-  /* Can't check ss->formatScanClosure. */
+  CHECKL(FUNCHECK(ss->areaScan));
+  /* Can't check ss->areaScanClosure. */
   CHECKL(FUNCHECK(ss->fix));
   /* Can't check ss->fixClosure. */
   CHECKL(ScanStateZoneShift(ss) == ss->arena->zoneShift);
@@ -58,20 +59,12 @@ Bool ScanStateCheck(ScanState ss)
 }
 
 
-/* traceNoScan -- Area scan method that must not be called. */
+/* traceNoAreaScan -- area scan function that must not be called */
 
-static mps_res_t traceNoScan(mps_ss_t ss, void *base, void *limit, void *closure)
+static mps_res_t traceNoAreaScan(mps_ss_t ss, void *base, void *limit, void *closure)
 {
-  UNUSED(ss);
-
-  AVER(base != NULL);
-  AVER(limit != NULL);
-  AVER(base < limit);
-  AVER(closure == UNUSED_POINTER);
-
-  NOTREACHED;
-
-  return MPS_RES_UNIMPL;
+  UNUSED(closure);
+  return FormatNoScan(ss, base, limit);
 }
 
 
@@ -110,8 +103,8 @@ void ScanStateInit(ScanState ss, TraceSet ts, Arena arena,
   if (ss->fix == SegFix && ArenaEmergency(arena))
         ss->fix = SegFixEmergency;
 
-  ss->formatScan = traceNoScan;
-  ss->formatScanClosure = UNUSED_POINTER;
+  ss->formatScan = FormatNoScan;
+  ss->areaScan = traceNoAreaScan;
   ss->rank = rank;
   ss->traces = ts;
   ScanStateSetZoneShift(ss, arena->zoneShift);
@@ -135,24 +128,6 @@ void ScanStateInit(ScanState ss, TraceSet ts, Arena arena,
 }
 
 
-/* traceFormatScan -- Area scan method that dispatches to a format scan.
- *
- * This is a wrapper for formatted object scanning functions, which
- * should not otherwise be called directly from within the MPS.
- */
-static mps_res_t traceFormatScan(mps_ss_t mps_ss, void *base, void *limit, void *closure)
-{
-  Format format = closure;
-
-  AVER_CRITICAL(base != NULL);
-  AVER_CRITICAL(limit != NULL);
-  AVER_CRITICAL(base < limit);
-  AVERT_CRITICAL(Format, format);
-
-  return format->scan(mps_ss, base, limit);
-}
-
-
 /* ScanStateInitSeg -- Initialize a ScanState object for scanning a segment */
 
 void ScanStateInitSeg(ScanState ss, TraceSet ts, Arena arena,
@@ -163,8 +138,7 @@ void ScanStateInitSeg(ScanState ss, TraceSet ts, Arena arena,
 
   ScanStateInit(ss, ts, arena, rank, white);
   if (PoolFormat(&format, SegPool(seg))) {
-    ss->formatScan = traceFormatScan;
-    ss->formatScanClosure = format;
+    ss->formatScan = format->scan;
   }
 }
 
@@ -1561,7 +1535,7 @@ Res TraceScanFormat(ScanState ss, Addr base, Addr limit)
    * ss->formatScan. */
   ss->scannedSize += AddrOffset(base, limit);
 
-  return ss->formatScan(&ss->ss_s, base, limit, ss->formatScanClosure);
+  return ss->formatScan(&ss->ss_s, base, limit);
 }
 
 

code/walk.c

@@ -398,6 +398,21 @@ static Res walkNoFix(Seg seg, ScanState ss, Addr *refIO)
 }
 
 
+/* poolWalkScan -- format scanner for poolWalk */
+
+static mps_res_t poolWalkScan(mps_ss_t mps_ss, void *base, void *limit)
+{
+  ScanState ss = PARENT(ScanStateStruct, ss_s, mps_ss);
+
+  AVERT(ScanState, ss);
+  AVER(base != NULL);
+  AVER(limit != NULL);
+  AVER(base < limit);
+
+  return ss->areaScan(mps_ss, base, limit, ss->areaScanClosure);
+}
+
+
 /* poolWalk -- walk formatted areas in a pool
  *
  * See <design/walk>.
@@ -432,8 +447,9 @@ static Res poolWalk(Arena arena, Pool pool, mps_area_scan_t area_scan, void *clo
   ts = TraceSetSingle(trace);
 
   ScanStateInit(&ss, ts, arena, RankEXACT, trace->white);
-  ss.formatScan = area_scan;
-  ss.formatScanClosure = closure;
+  ss.formatScan = poolWalkScan;
+  ss.areaScan = area_scan;
+  ss.areaScanClosure = closure;
   ss.fix = walkNoFix;
 
   RING_FOR(node, &pool->segRing, nextNode) {

design/walk.txt

@@ -92,7 +92,7 @@ _`.sol.walk.perf`: The callback uses the scanning protocol so that
 every reference is fixed and the summary is maintained.
 
 _`.sol.walk.closure`: ``mps_pool_walk()`` takes a closure pointer
-which is passed to the callback.
+which is stored in the ``ScanState`` and passed to the callback.
 
 _`.sol.walk.maint`: We reuse the scanning protocol and provide a
 generic implementation that iterates over the ring of segments in the