match file names to type names

Lots of changes but it's all just moving things around.
Backward-compatible stub #include's have been provided for now.

upb_Arena/upb_Status have been split out from upb/upb.?
upb_Array/upb_Map/upb_MessageValue have been split out from upb/collections.?
upb_ExtensionRegistry has been split out from upb/msg.?
upb/decode_internal.h is now upb/internal/decode.h
upb/mini_table_accessors_internal.h is now upb/internal/mini_table_accessors.h
upb/table_internal.h is now upb/internal/table.h
upb/upb_internal.h is now upb/internal/upb.h

PiperOrigin-RevId: 456297617

upb/arena.c

diff --git a/upb/arena.c b/upb/arena.c
new file mode 100644
index 0000000..3c87269
--- /dev/null
+++ b/upb/arena.c
@@ -0,0 +1,277 @@
+/*
+ * Copyright (c) 2009-2021, Google LLC
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *     * Redistributions of source code must retain the above copyright
+ *       notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above copyright
+ *       notice, this list of conditions and the following disclaimer in the
+ *       documentation and/or other materials provided with the distribution.
+ *     * Neither the name of Google LLC nor the
+ *       names of its contributors may be used to endorse or promote products
+ *       derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL Google LLC BE LIABLE FOR ANY DIRECT,
+ * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include "upb/arena.h"
+
+#include <stdlib.h>
+
+#include "upb/internal/upb.h"
+
+// Must be last.
+#include "upb/port_def.inc"
+
+/* upb_alloc ******************************************************************/
+
+static void* upb_global_allocfunc(upb_alloc* alloc, void* ptr, size_t oldsize,
+                                  size_t size) {
+  UPB_UNUSED(alloc);
+  UPB_UNUSED(oldsize);
+  if (size == 0) {
+    free(ptr);
+    return NULL;
+  } else {
+    return realloc(ptr, size);
+  }
+}
+
+static uint32_t* upb_cleanup_pointer(uintptr_t cleanup_metadata) {
+  return (uint32_t*)(cleanup_metadata & ~0x1);
+}
+
+static bool upb_cleanup_has_initial_block(uintptr_t cleanup_metadata) {
+  return cleanup_metadata & 0x1;
+}
+
+static uintptr_t upb_cleanup_metadata(uint32_t* cleanup,
+                                      bool has_initial_block) {
+  return (uintptr_t)cleanup | has_initial_block;
+}
+
+upb_alloc upb_alloc_global = {&upb_global_allocfunc};
+
+/* upb_Arena ******************************************************************/
+
+struct mem_block {
+  struct mem_block* next;
+  uint32_t size;
+  uint32_t cleanups;
+  /* Data follows. */
+};
+
+typedef struct cleanup_ent {
+  upb_CleanupFunc* cleanup;
+  void* ud;
+} cleanup_ent;
+
+static const size_t memblock_reserve =
+    UPB_ALIGN_UP(sizeof(mem_block), UPB_MALLOC_ALIGN);
+
+static upb_Arena* arena_findroot(upb_Arena* a) {
+  /* Path splitting keeps time complexity down, see:
+   *   https://en.wikipedia.org/wiki/Disjoint-set_data_structure */
+  while (a->parent != a) {
+    upb_Arena* next = a->parent;
+    a->parent = next->parent;
+    a = next;
+  }
+  return a;
+}
+
+static void upb_Arena_addblock(upb_Arena* a, upb_Arena* root, void* ptr,
+                               size_t size) {
+  mem_block* block = ptr;
+
+  /* The block is for arena |a|, but should appear in the freelist of |root|. */
+  block->next = root->freelist;
+  block->size = (uint32_t)size;
+  block->cleanups = 0;
+  root->freelist = block;
+  a->last_size = block->size;
+  if (!root->freelist_tail) root->freelist_tail = block;
+
+  a->head.ptr = UPB_PTR_AT(block, memblock_reserve, char);
+  a->head.end = UPB_PTR_AT(block, size, char);
+  a->cleanup_metadata = upb_cleanup_metadata(
+      &block->cleanups, upb_cleanup_has_initial_block(a->cleanup_metadata));
+
+  UPB_POISON_MEMORY_REGION(a->head.ptr, a->head.end - a->head.ptr);
+}
+
+static bool upb_Arena_Allocblock(upb_Arena* a, size_t size) {
+  upb_Arena* root = arena_findroot(a);
+  size_t block_size = UPB_MAX(size, a->last_size * 2) + memblock_reserve;
+  mem_block* block = upb_malloc(root->block_alloc, block_size);
+
+  if (!block) return false;
+  upb_Arena_addblock(a, root, block, block_size);
+  return true;
+}
+
+void* _upb_Arena_SlowMalloc(upb_Arena* a, size_t size) {
+  if (!upb_Arena_Allocblock(a, size)) return NULL; /* Out of memory. */
+  UPB_ASSERT(_upb_ArenaHas(a) >= size);
+  return upb_Arena_Malloc(a, size);
+}
+
+static void* upb_Arena_doalloc(upb_alloc* alloc, void* ptr, size_t oldsize,
+                               size_t size) {
+  upb_Arena* a = (upb_Arena*)alloc; /* upb_alloc is initial member. */
+  return upb_Arena_Realloc(a, ptr, oldsize, size);
+}
+
+/* Public Arena API ***********************************************************/
+
+upb_Arena* arena_initslow(void* mem, size_t n, upb_alloc* alloc) {
+  const size_t first_block_overhead = sizeof(upb_Arena) + memblock_reserve;
+  upb_Arena* a;
+
+  /* We need to malloc the initial block. */
+  n = first_block_overhead + 256;
+  if (!alloc || !(mem = upb_malloc(alloc, n))) {
+    return NULL;
+  }
+
+  a = UPB_PTR_AT(mem, n - sizeof(*a), upb_Arena);
+  n -= sizeof(*a);
+
+  a->head.alloc.func = &upb_Arena_doalloc;
+  a->block_alloc = alloc;
+  a->parent = a;
+  a->refcount = 1;
+  a->freelist = NULL;
+  a->freelist_tail = NULL;
+  a->cleanup_metadata = upb_cleanup_metadata(NULL, false);
+
+  upb_Arena_addblock(a, a, mem, n);
+
+  return a;
+}
+
+upb_Arena* upb_Arena_Init(void* mem, size_t n, upb_alloc* alloc) {
+  upb_Arena* a;
+
+  if (n) {
+    /* Align initial pointer up so that we return properly-aligned pointers. */
+    void* aligned = (void*)UPB_ALIGN_UP((uintptr_t)mem, UPB_MALLOC_ALIGN);
+    size_t delta = (uintptr_t)aligned - (uintptr_t)mem;
+    n = delta <= n ? n - delta : 0;
+    mem = aligned;
+  }
+
+  /* Round block size down to alignof(*a) since we will allocate the arena
+   * itself at the end. */
+  n = UPB_ALIGN_DOWN(n, UPB_ALIGN_OF(upb_Arena));
+
+  if (UPB_UNLIKELY(n < sizeof(upb_Arena))) {
+    return arena_initslow(mem, n, alloc);
+  }
+
+  a = UPB_PTR_AT(mem, n - sizeof(*a), upb_Arena);
+
+  a->head.alloc.func = &upb_Arena_doalloc;
+  a->block_alloc = alloc;
+  a->parent = a;
+  a->refcount = 1;
+  a->last_size = UPB_MAX(128, n);
+  a->head.ptr = mem;
+  a->head.end = UPB_PTR_AT(mem, n - sizeof(*a), char);
+  a->freelist = NULL;
+  a->cleanup_metadata = upb_cleanup_metadata(NULL, true);
+
+  return a;
+}
+
+static void arena_dofree(upb_Arena* a) {
+  mem_block* block = a->freelist;
+  UPB_ASSERT(a->parent == a);
+  UPB_ASSERT(a->refcount == 0);
+
+  while (block) {
+    /* Load first since we are deleting block. */
+    mem_block* next = block->next;
+
+    if (block->cleanups > 0) {
+      cleanup_ent* end = UPB_PTR_AT(block, block->size, void);
+      cleanup_ent* ptr = end - block->cleanups;
+
+      for (; ptr < end; ptr++) {
+        ptr->cleanup(ptr->ud);
+      }
+    }
+
+    upb_free(a->block_alloc, block);
+    block = next;
+  }
+}
+
+void upb_Arena_Free(upb_Arena* a) {
+  a = arena_findroot(a);
+  if (--a->refcount == 0) arena_dofree(a);
+}
+
+bool upb_Arena_AddCleanup(upb_Arena* a, void* ud, upb_CleanupFunc* func) {
+  cleanup_ent* ent;
+  uint32_t* cleanups = upb_cleanup_pointer(a->cleanup_metadata);
+
+  if (!cleanups || _upb_ArenaHas(a) < sizeof(cleanup_ent)) {
+    if (!upb_Arena_Allocblock(a, 128)) return false; /* Out of memory. */
+    UPB_ASSERT(_upb_ArenaHas(a) >= sizeof(cleanup_ent));
+    cleanups = upb_cleanup_pointer(a->cleanup_metadata);
+  }
+
+  a->head.end -= sizeof(cleanup_ent);
+  ent = (cleanup_ent*)a->head.end;
+  (*cleanups)++;
+  UPB_UNPOISON_MEMORY_REGION(ent, sizeof(cleanup_ent));
+
+  ent->cleanup = func;
+  ent->ud = ud;
+
+  return true;
+}
+
+bool upb_Arena_Fuse(upb_Arena* a1, upb_Arena* a2) {
+  upb_Arena* r1 = arena_findroot(a1);
+  upb_Arena* r2 = arena_findroot(a2);
+
+  if (r1 == r2) return true; /* Already fused. */
+
+  /* Do not fuse initial blocks since we cannot lifetime extend them. */
+  if (upb_cleanup_has_initial_block(r1->cleanup_metadata)) return false;
+  if (upb_cleanup_has_initial_block(r2->cleanup_metadata)) return false;
+
+  /* Only allow fuse with a common allocator */
+  if (r1->block_alloc != r2->block_alloc) return false;
+
+  /* We want to join the smaller tree to the larger tree.
+   * So swap first if they are backwards. */
+  if (r1->refcount < r2->refcount) {
+    upb_Arena* tmp = r1;
+    r1 = r2;
+    r2 = tmp;
+  }
+
+  /* r1 takes over r2's freelist and refcount. */
+  r1->refcount += r2->refcount;
+  if (r2->freelist_tail) {
+    UPB_ASSERT(r2->freelist_tail->next == NULL);
+    r2->freelist_tail->next = r1->freelist;
+    r1->freelist = r2->freelist;
+  }
+  r2->parent = r1;
+  return true;
+}