mdbx: add MDBX_PGWALK-tags and refine pgwalk internals.

Change-Id: I1f4eb79463dc6eec3d94d43baab0b28ceefa8c03

mdbx.h

@@ -1666,6 +1666,10 @@ typedef enum {
   MDBX_subpage_dupfixed_leaf
 } MDBX_page_type_t;
 
+#define MDBX_PGWALK_MAIN ((const char *)((ptrdiff_t)0))
+#define MDBX_PGWALK_GC ((const char *)((ptrdiff_t)-1))
+#define MDBX_PGWALK_META ((const char *)((ptrdiff_t)-2))
+
 typedef int MDBX_pgvisitor_func(uint64_t pgno, unsigned number, void *ctx,
                                 int deep, const char *dbi, size_t page_size,
                                 MDBX_page_type_t type, size_t nentries,

src/mdbx.c

@@ -12905,7 +12905,7 @@ static int __cold mdbx_env_walk(mdbx_walk_ctx_t *ctx, const char *dbi,
     payload_size += NODESIZE + NODEKSZ(node);
 
     if (type == MDBX_page_branch) {
-      rc = mdbx_env_walk(ctx, dbi, NODEPGNO(node), deep);
+      rc = mdbx_env_walk(ctx, dbi, NODEPGNO(node), deep + 1);
       if (rc)
         return rc;
       continue;
@@ -13056,15 +13056,16 @@ int __cold mdbx_env_pgwalk(MDBX_txn *txn, MDBX_pgvisitor_func *visitor,
   ctx.mw_visitor = visitor;
 
   int rc = visitor(
-      0, NUM_METAS, user, -2, "@META", pgno2bytes(txn->mt_env, NUM_METAS),
+      0, NUM_METAS, user, 0, MDBX_PGWALK_META,
-      MDBX_page_meta, NUM_METAS, sizeof(MDBX_meta) * NUM_METAS,
+      pgno2bytes(txn->mt_env, NUM_METAS), MDBX_page_meta, NUM_METAS,
-      PAGEHDRSZ * NUM_METAS,
+      sizeof(MDBX_meta) * NUM_METAS, PAGEHDRSZ * NUM_METAS,
       (txn->mt_env->me_psize - sizeof(MDBX_meta) - PAGEHDRSZ) * NUM_METAS);
-  if (!rc)
+  if (!MDBX_IS_ERROR(rc))
-    rc = mdbx_env_walk(&ctx, "@GC", txn->mt_dbs[FREE_DBI].md_root, -1);
+    rc = mdbx_env_walk(&ctx, MDBX_PGWALK_GC, txn->mt_dbs[FREE_DBI].md_root, 0);
-  if (!rc)
+  if (!MDBX_IS_ERROR(rc))
-    rc = mdbx_env_walk(&ctx, "@MAIN", txn->mt_dbs[MAIN_DBI].md_root, 0);
+    rc =
-  if (!rc)
+        mdbx_env_walk(&ctx, MDBX_PGWALK_MAIN, txn->mt_dbs[MAIN_DBI].md_root, 0);
+  if (!MDBX_IS_ERROR(rc))
     rc = visitor(P_INVALID, 0, user, INT_MIN, NULL, 0, MDBX_page_void, 0, 0, 0,
                  0);
   return rc;

src/tools/mdbx_chk.c

@@ -154,6 +154,13 @@ static void pagemap_cleanup(void) {
 static walk_dbi_t *pagemap_lookup_dbi(const char *dbi_name, bool silent) {
   static walk_dbi_t *last;
 
+  if (dbi_name == MDBX_PGWALK_MAIN)
+    return &dbi_main;
+  if (dbi_name == MDBX_PGWALK_GC)
+    return &dbi_free;
+  if (dbi_name == MDBX_PGWALK_META)
+    return &dbi_meta;
+
   if (last && strcmp(last->name, dbi_name) == 0)
     return last;
 
@@ -246,7 +253,7 @@ static size_t problems_pop(struct problem *list) {
 }
 
 static int pgvisitor(uint64_t pgno, unsigned pgnumber, void *ctx, int deep,
-                     const char *dbi_name, size_t page_size,
+                     const char *dbi_name_or_tag, size_t page_size,
                      MDBX_page_type_t pagetype, size_t nentries,
                      size_t payload_bytes, size_t header_bytes,
                      size_t unused_bytes) {
@@ -254,19 +261,9 @@ static int pgvisitor(uint64_t pgno, unsigned pgnumber, void *ctx, int deep,
   if (pagetype == MDBX_page_void)
     return MDBX_SUCCESS;
 
-  walk_dbi_t fake, *dbi = &fake;
+  walk_dbi_t *dbi = pagemap_lookup_dbi(dbi_name_or_tag, false);
-  if (deep > 0) {
+  if (!dbi)
-    dbi = pagemap_lookup_dbi(dbi_name, false);
+    return MDBX_ENOMEM;
-    if (!dbi)
-      return MDBX_ENOMEM;
-  } else if (deep == 0 && strcmp(dbi_name, dbi_main.name) == 0)
-    dbi = &dbi_main;
-  else if (deep == -1 && strcmp(dbi_name, dbi_free.name) == 0)
-    dbi = &dbi_free;
-  else if (deep == -2 && strcmp(dbi_name, dbi_meta.name) == 0)
-    dbi = &dbi_meta;
-  else
-    problem_add("deep", deep, "unknown area", "%s", dbi_name);
 
   const size_t page_bytes = payload_bytes + header_bytes + unused_bytes;
   walk.pgcount += pgnumber;
@@ -310,14 +307,14 @@ static int pgvisitor(uint64_t pgno, unsigned pgnumber, void *ctx, int deep,
   }
 
   if (pgnumber) {
-    if (verbose > 3 && (!only_subdb || strcmp(only_subdb, dbi_name) == 0)) {
+    if (verbose > 3 && (!only_subdb || strcmp(only_subdb, dbi->name) == 0)) {
       if (pgnumber == 1)
         print("     %s-page %" PRIu64, pagetype_caption, pgno);
       else
         print("     %s-span %" PRIu64 "[%u]", pagetype_caption, pgno, pgnumber);
       print(" of %s: header %" PRIiPTR ", payload %" PRIiPTR
-            ", unused %" PRIiPTR "\n",
+            ", unused %" PRIiPTR ", deep %i\n",
-            dbi_name, header_bytes, payload_bytes, unused_bytes);
+            dbi->name, header_bytes, payload_bytes, unused_bytes, deep);
     }
   }
 
@@ -343,8 +340,9 @@ static int pgvisitor(uint64_t pgno, unsigned pgnumber, void *ctx, int deep,
       } */
     } else {
       problem_add("page", pgno, "empty",
-                  "%s-page: payload %" PRIuPTR " bytes, %" PRIuPTR " entries",
+                  "%s-page: payload %" PRIuPTR " bytes, %" PRIuPTR
-                  pagetype_caption, payload_bytes, nentries);
+                  " entries, deep %i",
+                  pagetype_caption, payload_bytes, nentries, deep);
       dbi->pages.empty += 1;
     }
   }
@@ -353,9 +351,9 @@ static int pgvisitor(uint64_t pgno, unsigned pgnumber, void *ctx, int deep,
     if (page_bytes != page_size) {
       problem_add("page", pgno, "misused",
                   "%s-page: %" PRIuPTR " != %" PRIuPTR " (%" PRIuPTR
-                  "h + %" PRIuPTR "p + %" PRIuPTR "u)",
+                  "h + %" PRIuPTR "p + %" PRIuPTR "u), deep %i",
                   pagetype_caption, page_size, page_bytes, header_bytes,
-                  payload_bytes, unused_bytes);
+                  payload_bytes, unused_bytes, deep);
       if (page_size > page_bytes)
         dbi->lost_bytes += page_size - page_bytes;
     } else {