Adding upstream version 3.40.1.upstream/3.40.1upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1181 insertions, 0 deletions

diff --git a/ext/wasm/api/sqlite3-wasm.c b/ext/wasm/api/sqlite3-wasm.c
new file mode 100644
index 0000000..af5ed6b
--- /dev/null
+++ b/ext/wasm/api/sqlite3-wasm.c
@@ -0,0 +1,1181 @@
+/*
+** This file requires access to sqlite3.c static state in order to
+** implement certain WASM-specific features, and thus directly
+** includes that file. Unlike the rest of sqlite3.c, this file
+** requires compiling with -std=c99 (or equivalent, or a later C
+** version) because it makes use of features not available in C89.
+**
+** At its simplest, to build sqlite3.wasm either place this file
+** in the same directory as sqlite3.c/h before compilation or use the
+** -I/path flag to tell the compiler where to find both of those
+** files, then compile this file. For example:
+**
+** emcc -o sqlite3.wasm ... -I/path/to/sqlite3-c-and-h sqlite3-wasm.c
+*/
+#define SQLITE_WASM
+#ifdef SQLITE_WASM_ENABLE_C_TESTS
+/*
+** Code blocked off by SQLITE_WASM_TESTS is intended solely for use in
+** unit/regression testing. They may be safely omitted from
+** client-side builds. The main unit test script, tester1.js, will
+** skip related tests if it doesn't find the corresponding functions
+** in the WASM exports.
+*/
+#  define SQLITE_WASM_TESTS 1
+#else
+#  define SQLITE_WASM_TESTS 0
+#endif
+
+/*
+** Threading and file locking: JS is single-threaded. Each Worker
+** thread is a separate instance of the JS engine so can never access
+** the same db handle as another thread, thus multi-threading support
+** is unnecessary in the library. Because the filesystems are virtual
+** and local to a given wasm runtime instance, two Workers can never
+** access the same db file at once, with the exception of OPFS. As of
+** this writing (2022-09-30), OPFS exclusively locks a file when
+** opening it, so two Workers can never open the same OPFS-backed file
+** at once. That situation will change if and when lower-level locking
+** features are added to OPFS (as is currently planned, per folks
+** involved with its development).
+**
+** Summary: except for the case of future OPFS, which supports
+** locking, and any similar future filesystems, threading and file
+** locking support are unnecessary in the wasm build.
+*/
+
+/*
+** Undefine any SQLITE_... config flags which we specifically do not
+** want undefined. Please keep these alphabetized.
+*/
+#undef SQLITE_OMIT_DESERIALIZE
+#undef SQLITE_OMIT_MEMORYDB
+
+/*
+** Define any SQLITE_... config defaults we want if they aren't
+** overridden by the builder. Please keep these alphabetized.
+*/
+
+/**********************************************************************/
+/* SQLITE_D... */
+#ifndef SQLITE_DEFAULT_CACHE_SIZE
+/*
+** The OPFS impls benefit tremendously from an increased cache size
+** when working on large workloads, e.g. speedtest1 --size 50 or
+** higher. On smaller workloads, e.g. speedtest1 --size 25, they
+** clearly benefit from having 4mb of cache, but not as much as a
+** larger cache benefits the larger workloads. Speed differences
+** between 2x and nearly 3x have been measured with ample page cache.
+*/
+# define SQLITE_DEFAULT_CACHE_SIZE -16384
+#endif
+#if 0 && !defined(SQLITE_DEFAULT_PAGE_SIZE)
+/* TODO: experiment with this. */
+# define SQLITE_DEFAULT_PAGE_SIZE 8192 /*4096*/
+#endif
+#ifndef SQLITE_DEFAULT_UNIX_VFS
+# define SQLITE_DEFAULT_UNIX_VFS "unix-none"
+#endif
+#undef SQLITE_DQS
+#define SQLITE_DQS 0
+
+/**********************************************************************/
+/* SQLITE_ENABLE_... */
+#ifndef SQLITE_ENABLE_BYTECODE_VTAB
+#  define SQLITE_ENABLE_BYTECODE_VTAB 1
+#endif
+#ifndef SQLITE_ENABLE_DBPAGE_VTAB
+#  define SQLITE_ENABLE_DBPAGE_VTAB 1
+#endif
+#ifndef SQLITE_ENABLE_DBSTAT_VTAB
+#  define SQLITE_ENABLE_DBSTAT_VTAB 1
+#endif
+#ifndef SQLITE_ENABLE_EXPLAIN_COMMENTS
+#  define SQLITE_ENABLE_EXPLAIN_COMMENTS 1
+#endif
+#ifndef SQLITE_ENABLE_FTS4
+#  define SQLITE_ENABLE_FTS4 1
+#endif
+#ifndef SQLITE_ENABLE_OFFSET_SQL_FUNC
+#  define SQLITE_ENABLE_OFFSET_SQL_FUNC 1
+#endif
+#ifndef SQLITE_ENABLE_RTREE
+#  define SQLITE_ENABLE_RTREE 1
+#endif
+#ifndef SQLITE_ENABLE_STMTVTAB
+#  define SQLITE_ENABLE_STMTVTAB 1
+#endif
+#ifndef SQLITE_ENABLE_UNKNOWN_SQL_FUNCTION
+#  define SQLITE_ENABLE_UNKNOWN_SQL_FUNCTION
+#endif
+
+/**********************************************************************/
+/* SQLITE_O... */
+#ifndef SQLITE_OMIT_DEPRECATED
+# define SQLITE_OMIT_DEPRECATED 1
+#endif
+#ifndef SQLITE_OMIT_LOAD_EXTENSION
+# define SQLITE_OMIT_LOAD_EXTENSION 1
+#endif
+#ifndef SQLITE_OMIT_SHARED_CACHE
+# define SQLITE_OMIT_SHARED_CACHE 1
+#endif
+#ifndef SQLITE_OMIT_UTF16
+# define SQLITE_OMIT_UTF16 1
+#endif
+#ifndef SQLITE_OMIT_WAL
+# define SQLITE_OMIT_WAL 1
+#endif
+#ifndef SQLITE_OS_KV_OPTIONAL
+# define SQLITE_OS_KV_OPTIONAL 1
+#endif
+
+/**********************************************************************/
+/* SQLITE_T... */
+#ifndef SQLITE_TEMP_STORE
+# define SQLITE_TEMP_STORE 3
+#endif
+#ifndef SQLITE_THREADSAFE
+# define SQLITE_THREADSAFE 0
+#endif
+
+/**********************************************************************/
+/* SQLITE_USE_... */
+#ifndef SQLITE_USE_URI
+#  define SQLITE_USE_URI 1
+#endif
+
+#include <assert.h>
+#include "sqlite3.c" /* yes, .c instead of .h. */
+
+#if defined(__EMSCRIPTEN__)
+#  include <emscripten/console.h>
+#endif
+
+/*
+** SQLITE_WASM_KEEP is functionally identical to EMSCRIPTEN_KEEPALIVE
+** but is not Emscripten-specific. It explicitly marks functions for
+** export into the target wasm file without requiring explicit listing
+** of those functions in Emscripten's -sEXPORTED_FUNCTIONS=... list
+** (or equivalent in other build platforms). Any function with neither
+** this attribute nor which is listed as an explicit export will not
+** be exported from the wasm file (but may still be used internally
+** within the wasm file).
+**
+** The functions in this file (sqlite3-wasm.c) which require exporting
+** are marked with this flag. They may also be added to any explicit
+** build-time export list but need not be. All of these APIs are
+** intended for use only within the project's own JS/WASM code, and
+** not by client code, so an argument can be made for reducing their
+** visibility by not including them in any build-time export lists.
+**
+** 2022-09-11: it's not yet _proven_ that this approach works in
+** non-Emscripten builds. If not, such builds will need to export
+** those using the --export=... wasm-ld flag (or equivalent). As of
+** this writing we are tied to Emscripten for various reasons
+** and cannot test the library with other build environments.
+*/
+#define SQLITE_WASM_KEEP __attribute__((used,visibility("default")))
+// See also:
+//__attribute__((export_name("theExportedName"), used, visibility("default")))
+
+
+#if 0
+/*
+** An EXPERIMENT in implementing a stack-based allocator analog to
+** Emscripten's stackSave(), stackAlloc(), stackRestore().
+** Unfortunately, this cannot work together with Emscripten because
+** Emscripten defines its own native one and we'd stomp on each
+** other's memory. Other than that complication, basic tests show it
+** to work just fine.
+**
+** Another option is to malloc() a chunk of our own and call that our
+** "stack".
+*/
+SQLITE_WASM_KEEP void * sqlite3_wasm_stack_end(void){
+  extern void __heap_base
+    /* see https://stackoverflow.com/questions/10038964 */;
+  return &__heap_base;
+}
+SQLITE_WASM_KEEP void * sqlite3_wasm_stack_begin(void){
+  extern void __data_end;
+  return &__data_end;
+}
+static void * pWasmStackPtr = 0;
+SQLITE_WASM_KEEP void * sqlite3_wasm_stack_ptr(void){
+  if(!pWasmStackPtr) pWasmStackPtr = sqlite3_wasm_stack_end();
+  return pWasmStackPtr;
+}
+SQLITE_WASM_KEEP void sqlite3_wasm_stack_restore(void * p){
+  pWasmStackPtr = p;
+}
+SQLITE_WASM_KEEP void * sqlite3_wasm_stack_alloc(int n){
+  if(n<=0) return 0;
+  n = (n + 7) & ~7 /* align to 8-byte boundary */;
+  unsigned char * const p = (unsigned char *)sqlite3_wasm_stack_ptr();
+  unsigned const char * const b = (unsigned const char *)sqlite3_wasm_stack_begin();
+  if(b + n >= p || b + n < b/*overflow*/) return 0;
+  return pWasmStackPtr = p - n;
+}
+#endif /* stack allocator experiment */
+
+/*
+** State for the "pseudo-stack" allocator implemented in
+** sqlite3_wasm_pstack_xyz(). In order to avoid colliding with
+** Emscripten-controled stack space, it carves out a bit of stack
+** memory to use for that purpose. This memory ends up in the
+** WASM-managed memory, such that routines which manipulate the wasm
+** heap can also be used to manipulate this memory.
+**
+** This particular allocator is intended for small allocations such as
+** storage for output pointers. We cannot reasonably size it large
+** enough for general-purpose string conversions because some of our
+** tests use input files (strings) of 16MB+.
+*/
+static unsigned char PStack_mem[512 * 8] = {0};
+static struct {
+  unsigned const char * const pBegin;/* Start (inclusive) of memory */
+  unsigned const char * const pEnd;  /* One-after-the-end of memory */
+  unsigned char * pPos;              /* Current stack pointer */
+} PStack = {
+  &PStack_mem[0],
+  &PStack_mem[0] + sizeof(PStack_mem),
+  &PStack_mem[0] + sizeof(PStack_mem)
+};
+/*
+** Returns the current pstack position.
+*/
+SQLITE_WASM_KEEP void * sqlite3_wasm_pstack_ptr(void){
+  return PStack.pPos;
+}
+/*
+** Sets the pstack position poitner to p. Results are undefined if the
+** given value did not come from sqlite3_wasm_pstack_ptr().
+*/
+SQLITE_WASM_KEEP void sqlite3_wasm_pstack_restore(unsigned char * p){
+  assert(p>=PStack.pBegin && p<=PStack.pEnd && p>=PStack.pPos);
+  assert(0==(p & 0x7));
+  if(p>=PStack.pBegin && p<=PStack.pEnd /*&& p>=PStack.pPos*/){
+    PStack.pPos = p;
+  }
+}
+/*
+** Allocate and zero out n bytes from the pstack. Returns a pointer to
+** the memory on success, 0 on error (including a negative n value). n
+** is always adjusted to be a multiple of 8 and returned memory is
+** always zeroed out before returning (because this keeps the client
+** JS code from having to do so, and most uses of the pstack will
+** call for doing so).
+*/
+SQLITE_WASM_KEEP void * sqlite3_wasm_pstack_alloc(int n){
+  if( n<=0 ) return 0;
+  //if( n & 0x7 ) n += 8 - (n & 0x7) /* align to 8-byte boundary */;
+  n = (n + 7) & ~7 /* align to 8-byte boundary */;
+  if( PStack.pBegin + n > PStack.pPos /*not enough space left*/
+      || PStack.pBegin + n <= PStack.pBegin /*overflow*/ ) return 0;
+  memset((PStack.pPos = PStack.pPos - n), 0, (unsigned int)n);
+  return PStack.pPos;
+}
+/*
+** Return the number of bytes left which can be
+** sqlite3_wasm_pstack_alloc()'d.
+*/
+SQLITE_WASM_KEEP int sqlite3_wasm_pstack_remaining(void){
+  assert(PStack.pPos >= PStack.pBegin);
+  assert(PStack.pPos <= PStack.pEnd);
+  return (int)(PStack.pPos - PStack.pBegin);
+}
+
+/*
+** Return the total number of bytes available in the pstack, including
+** any space which is currently allocated. This value is a
+** compile-time constant.
+*/
+SQLITE_WASM_KEEP int sqlite3_wasm_pstack_quota(void){
+  return (int)(PStack.pEnd - PStack.pBegin);
+}
+
+/*
+** This function is NOT part of the sqlite3 public API. It is strictly
+** for use by the sqlite project's own JS/WASM bindings.
+**
+** For purposes of certain hand-crafted C/Wasm function bindings, we
+** need a way of reporting errors which is consistent with the rest of
+** the C API, as opposed to throwing JS exceptions. To that end, this
+** internal-use-only function is a thin proxy around
+** sqlite3ErrorWithMessage(). The intent is that it only be used from
+** Wasm bindings such as sqlite3_prepare_v2/v3(), and definitely not
+** from client code.
+**
+** Returns err_code.
+*/
+SQLITE_WASM_KEEP
+int sqlite3_wasm_db_error(sqlite3*db, int err_code, const char *zMsg){
+  if( 0!=zMsg ){
+    const int nMsg = sqlite3Strlen30(zMsg);
+    sqlite3ErrorWithMsg(db, err_code, "%.*s", nMsg, zMsg);
+  }else{
+    sqlite3ErrorWithMsg(db, err_code, NULL);
+  }
+  return err_code;
+}
+
+#if SQLITE_WASM_TESTS
+struct WasmTestStruct {
+  int v4;
+  void * ppV;
+  const char * cstr;
+  int64_t v8;
+  void (*xFunc)(void*);
+};
+typedef struct WasmTestStruct WasmTestStruct;
+SQLITE_WASM_KEEP
+void sqlite3_wasm_test_struct(WasmTestStruct * s){
+  if(s){
+    s->v4 *= 2;
+    s->v8 = s->v4 * 2;
+    s->ppV = s;
+    s->cstr = __FILE__;
+    if(s->xFunc) s->xFunc(s);
+  }
+  return;
+}
+#endif /* SQLITE_WASM_TESTS */
+
+/*
+** This function is NOT part of the sqlite3 public API. It is strictly
+** for use by the sqlite project's own JS/WASM bindings. Unlike the
+** rest of the sqlite3 API, this part requires C99 for snprintf() and
+** variadic macros.
+**
+** Returns a string containing a JSON-format "enum" of C-level
+** constants and struct-related metadata intended to be imported into
+** the JS environment. The JSON is initialized the first time this
+** function is called and that result is reused for all future calls.
+**
+** If this function returns NULL then it means that the internal
+** buffer is not large enough for the generated JSON and needs to be
+** increased. In debug builds that will trigger an assert().
+*/
+SQLITE_WASM_KEEP
+const char * sqlite3_wasm_enum_json(void){
+  static char aBuffer[1024 * 12] = {0} /* where the JSON goes */;
+  int n = 0, nChildren = 0, nStruct = 0
+    /* output counters for figuring out where commas go */;
+  char * zPos = &aBuffer[1] /* skip first byte for now to help protect
+                          ** against a small race condition */;
+  char const * const zEnd = &aBuffer[0] + sizeof(aBuffer) /* one-past-the-end */;
+  if(aBuffer[0]) return aBuffer;
+  /* Leave aBuffer[0] at 0 until the end to help guard against a tiny
+  ** race condition. If this is called twice concurrently, they might
+  ** end up both writing to aBuffer, but they'll both write the same
+  ** thing, so that's okay. If we set byte 0 up front then the 2nd
+  ** instance might return and use the string before the 1st instance
+  ** is done filling it. */
+
+/* Core output macros... */
+#define lenCheck assert(zPos < zEnd - 128 \
+  && "sqlite3_wasm_enum_json() buffer is too small."); \
+  if( zPos >= zEnd - 128 ) return 0
+#define outf(format,...) \
+  zPos += snprintf(zPos, ((size_t)(zEnd - zPos)), format, __VA_ARGS__); \
+  lenCheck
+#define out(TXT) outf("%s",TXT)
+#define CloseBrace(LEVEL) \
+  assert(LEVEL<5); memset(zPos, '}', LEVEL); zPos+=LEVEL; lenCheck
+
+/* Macros for emitting maps of integer- and string-type macros to
+** their values. */
+#define DefGroup(KEY) n = 0; \
+  outf("%s\"" #KEY "\": {",(nChildren++ ? "," : ""));
+#define DefInt(KEY)                                     \
+  outf("%s\"%s\": %d", (n++ ? ", " : ""), #KEY, (int)KEY)
+#define DefStr(KEY)                                     \
+  outf("%s\"%s\": \"%s\"", (n++ ? ", " : ""), #KEY, KEY)
+#define _DefGroup CloseBrace(1)
+
+  /* The following groups are sorted alphabetic by group name. */
+  DefGroup(access){
+    DefInt(SQLITE_ACCESS_EXISTS);
+    DefInt(SQLITE_ACCESS_READWRITE);
+    DefInt(SQLITE_ACCESS_READ)/*docs say this is unused*/;
+  } _DefGroup;
+
+  DefGroup(blobFinalizers) {
+    /* SQLITE_STATIC/TRANSIENT need to be handled explicitly as
+    ** integers to avoid casting-related warnings. */
+    out("\"SQLITE_STATIC\":0, \"SQLITE_TRANSIENT\":-1");
+  } _DefGroup;
+
+  DefGroup(dataTypes) {
+    DefInt(SQLITE_INTEGER);
+    DefInt(SQLITE_FLOAT);
+    DefInt(SQLITE_TEXT);
+    DefInt(SQLITE_BLOB);
+    DefInt(SQLITE_NULL);
+  } _DefGroup;
+
+  DefGroup(encodings) {
+    /* Noting that the wasm binding only aims to support UTF-8. */
+    DefInt(SQLITE_UTF8);
+    DefInt(SQLITE_UTF16LE);
+    DefInt(SQLITE_UTF16BE);
+    DefInt(SQLITE_UTF16);
+    /*deprecated DefInt(SQLITE_ANY); */
+    DefInt(SQLITE_UTF16_ALIGNED);
+  } _DefGroup;
+
+  DefGroup(fcntl) {
+    DefInt(SQLITE_FCNTL_LOCKSTATE);
+    DefInt(SQLITE_FCNTL_GET_LOCKPROXYFILE);
+    DefInt(SQLITE_FCNTL_SET_LOCKPROXYFILE);
+    DefInt(SQLITE_FCNTL_LAST_ERRNO);
+    DefInt(SQLITE_FCNTL_SIZE_HINT);
+    DefInt(SQLITE_FCNTL_CHUNK_SIZE);
+    DefInt(SQLITE_FCNTL_FILE_POINTER);
+    DefInt(SQLITE_FCNTL_SYNC_OMITTED);
+    DefInt(SQLITE_FCNTL_WIN32_AV_RETRY);
+    DefInt(SQLITE_FCNTL_PERSIST_WAL);
+    DefInt(SQLITE_FCNTL_OVERWRITE);
+    DefInt(SQLITE_FCNTL_VFSNAME);
+    DefInt(SQLITE_FCNTL_POWERSAFE_OVERWRITE);
+    DefInt(SQLITE_FCNTL_PRAGMA);
+    DefInt(SQLITE_FCNTL_BUSYHANDLER);
+    DefInt(SQLITE_FCNTL_TEMPFILENAME);
+    DefInt(SQLITE_FCNTL_MMAP_SIZE);
+    DefInt(SQLITE_FCNTL_TRACE);
+    DefInt(SQLITE_FCNTL_HAS_MOVED);
+    DefInt(SQLITE_FCNTL_SYNC);
+    DefInt(SQLITE_FCNTL_COMMIT_PHASETWO);
+    DefInt(SQLITE_FCNTL_WIN32_SET_HANDLE);
+    DefInt(SQLITE_FCNTL_WAL_BLOCK);
+    DefInt(SQLITE_FCNTL_ZIPVFS);
+    DefInt(SQLITE_FCNTL_RBU);
+    DefInt(SQLITE_FCNTL_VFS_POINTER);
+    DefInt(SQLITE_FCNTL_JOURNAL_POINTER);
+    DefInt(SQLITE_FCNTL_WIN32_GET_HANDLE);
+    DefInt(SQLITE_FCNTL_PDB);
+    DefInt(SQLITE_FCNTL_BEGIN_ATOMIC_WRITE);
+    DefInt(SQLITE_FCNTL_COMMIT_ATOMIC_WRITE);
+    DefInt(SQLITE_FCNTL_ROLLBACK_ATOMIC_WRITE);
+    DefInt(SQLITE_FCNTL_LOCK_TIMEOUT);
+    DefInt(SQLITE_FCNTL_DATA_VERSION);
+    DefInt(SQLITE_FCNTL_SIZE_LIMIT);
+    DefInt(SQLITE_FCNTL_CKPT_DONE);
+    DefInt(SQLITE_FCNTL_RESERVE_BYTES);
+    DefInt(SQLITE_FCNTL_CKPT_START);
+    DefInt(SQLITE_FCNTL_EXTERNAL_READER);
+    DefInt(SQLITE_FCNTL_CKSM_FILE);
+  } _DefGroup;
+
+  DefGroup(flock) {
+    DefInt(SQLITE_LOCK_NONE);
+    DefInt(SQLITE_LOCK_SHARED);
+    DefInt(SQLITE_LOCK_RESERVED);
+    DefInt(SQLITE_LOCK_PENDING);
+    DefInt(SQLITE_LOCK_EXCLUSIVE);
+  } _DefGroup;
+
+  DefGroup(ioCap) {
+    DefInt(SQLITE_IOCAP_ATOMIC);
+    DefInt(SQLITE_IOCAP_ATOMIC512);
+    DefInt(SQLITE_IOCAP_ATOMIC1K);
+    DefInt(SQLITE_IOCAP_ATOMIC2K);
+    DefInt(SQLITE_IOCAP_ATOMIC4K);
+    DefInt(SQLITE_IOCAP_ATOMIC8K);
+    DefInt(SQLITE_IOCAP_ATOMIC16K);
+    DefInt(SQLITE_IOCAP_ATOMIC32K);
+    DefInt(SQLITE_IOCAP_ATOMIC64K);
+    DefInt(SQLITE_IOCAP_SAFE_APPEND);
+    DefInt(SQLITE_IOCAP_SEQUENTIAL);
+    DefInt(SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN);
+    DefInt(SQLITE_IOCAP_POWERSAFE_OVERWRITE);
+    DefInt(SQLITE_IOCAP_IMMUTABLE);
+    DefInt(SQLITE_IOCAP_BATCH_ATOMIC);
+  } _DefGroup;
+
+  DefGroup(openFlags) {
+    /* Noting that not all of these will have any effect in
+    ** WASM-space. */
+    DefInt(SQLITE_OPEN_READONLY);
+    DefInt(SQLITE_OPEN_READWRITE);
+    DefInt(SQLITE_OPEN_CREATE);
+    DefInt(SQLITE_OPEN_URI);
+    DefInt(SQLITE_OPEN_MEMORY);
+    DefInt(SQLITE_OPEN_NOMUTEX);
+    DefInt(SQLITE_OPEN_FULLMUTEX);
+    DefInt(SQLITE_OPEN_SHAREDCACHE);
+    DefInt(SQLITE_OPEN_PRIVATECACHE);
+    DefInt(SQLITE_OPEN_EXRESCODE);
+    DefInt(SQLITE_OPEN_NOFOLLOW);
+    /* OPEN flags for use with VFSes... */
+    DefInt(SQLITE_OPEN_MAIN_DB);
+    DefInt(SQLITE_OPEN_MAIN_JOURNAL);
+    DefInt(SQLITE_OPEN_TEMP_DB);
+    DefInt(SQLITE_OPEN_TEMP_JOURNAL);
+    DefInt(SQLITE_OPEN_TRANSIENT_DB);
+    DefInt(SQLITE_OPEN_SUBJOURNAL);
+    DefInt(SQLITE_OPEN_SUPER_JOURNAL);
+    DefInt(SQLITE_OPEN_WAL);
+    DefInt(SQLITE_OPEN_DELETEONCLOSE);
+    DefInt(SQLITE_OPEN_EXCLUSIVE);
+  } _DefGroup;
+
+  DefGroup(prepareFlags) {
+    DefInt(SQLITE_PREPARE_PERSISTENT);
+    DefInt(SQLITE_PREPARE_NORMALIZE);
+    DefInt(SQLITE_PREPARE_NO_VTAB);
+  } _DefGroup;
+
+  DefGroup(resultCodes) {
+    DefInt(SQLITE_OK);
+    DefInt(SQLITE_ERROR);
+    DefInt(SQLITE_INTERNAL);
+    DefInt(SQLITE_PERM);
+    DefInt(SQLITE_ABORT);
+    DefInt(SQLITE_BUSY);
+    DefInt(SQLITE_LOCKED);
+    DefInt(SQLITE_NOMEM);
+    DefInt(SQLITE_READONLY);
+    DefInt(SQLITE_INTERRUPT);
+    DefInt(SQLITE_IOERR);
+    DefInt(SQLITE_CORRUPT);
+    DefInt(SQLITE_NOTFOUND);
+    DefInt(SQLITE_FULL);
+    DefInt(SQLITE_CANTOPEN);
+    DefInt(SQLITE_PROTOCOL);
+    DefInt(SQLITE_EMPTY);
+    DefInt(SQLITE_SCHEMA);
+    DefInt(SQLITE_TOOBIG);
+    DefInt(SQLITE_CONSTRAINT);
+    DefInt(SQLITE_MISMATCH);
+    DefInt(SQLITE_MISUSE);
+    DefInt(SQLITE_NOLFS);
+    DefInt(SQLITE_AUTH);
+    DefInt(SQLITE_FORMAT);
+    DefInt(SQLITE_RANGE);
+    DefInt(SQLITE_NOTADB);
+    DefInt(SQLITE_NOTICE);
+    DefInt(SQLITE_WARNING);
+    DefInt(SQLITE_ROW);
+    DefInt(SQLITE_DONE);
+    // Extended Result Codes
+    DefInt(SQLITE_ERROR_MISSING_COLLSEQ);
+    DefInt(SQLITE_ERROR_RETRY);
+    DefInt(SQLITE_ERROR_SNAPSHOT);
+    DefInt(SQLITE_IOERR_READ);
+    DefInt(SQLITE_IOERR_SHORT_READ);
+    DefInt(SQLITE_IOERR_WRITE);
+    DefInt(SQLITE_IOERR_FSYNC);
+    DefInt(SQLITE_IOERR_DIR_FSYNC);
+    DefInt(SQLITE_IOERR_TRUNCATE);
+    DefInt(SQLITE_IOERR_FSTAT);
+    DefInt(SQLITE_IOERR_UNLOCK);
+    DefInt(SQLITE_IOERR_RDLOCK);
+    DefInt(SQLITE_IOERR_DELETE);
+    DefInt(SQLITE_IOERR_BLOCKED);
+    DefInt(SQLITE_IOERR_NOMEM);
+    DefInt(SQLITE_IOERR_ACCESS);
+    DefInt(SQLITE_IOERR_CHECKRESERVEDLOCK);
+    DefInt(SQLITE_IOERR_LOCK);
+    DefInt(SQLITE_IOERR_CLOSE);
+    DefInt(SQLITE_IOERR_DIR_CLOSE);
+    DefInt(SQLITE_IOERR_SHMOPEN);
+    DefInt(SQLITE_IOERR_SHMSIZE);
+    DefInt(SQLITE_IOERR_SHMLOCK);
+    DefInt(SQLITE_IOERR_SHMMAP);
+    DefInt(SQLITE_IOERR_SEEK);
+    DefInt(SQLITE_IOERR_DELETE_NOENT);
+    DefInt(SQLITE_IOERR_MMAP);
+    DefInt(SQLITE_IOERR_GETTEMPPATH);
+    DefInt(SQLITE_IOERR_CONVPATH);
+    DefInt(SQLITE_IOERR_VNODE);
+    DefInt(SQLITE_IOERR_AUTH);
+    DefInt(SQLITE_IOERR_BEGIN_ATOMIC);
+    DefInt(SQLITE_IOERR_COMMIT_ATOMIC);
+    DefInt(SQLITE_IOERR_ROLLBACK_ATOMIC);
+    DefInt(SQLITE_IOERR_DATA);
+    DefInt(SQLITE_IOERR_CORRUPTFS);
+    DefInt(SQLITE_LOCKED_SHAREDCACHE);
+    DefInt(SQLITE_LOCKED_VTAB);
+    DefInt(SQLITE_BUSY_RECOVERY);
+    DefInt(SQLITE_BUSY_SNAPSHOT);
+    DefInt(SQLITE_BUSY_TIMEOUT);
+    DefInt(SQLITE_CANTOPEN_NOTEMPDIR);
+    DefInt(SQLITE_CANTOPEN_ISDIR);
+    DefInt(SQLITE_CANTOPEN_FULLPATH);
+    DefInt(SQLITE_CANTOPEN_CONVPATH);
+    //DefInt(SQLITE_CANTOPEN_DIRTYWAL)/*docs say not used*/;
+    DefInt(SQLITE_CANTOPEN_SYMLINK);
+    DefInt(SQLITE_CORRUPT_VTAB);
+    DefInt(SQLITE_CORRUPT_SEQUENCE);
+    DefInt(SQLITE_CORRUPT_INDEX);
+    DefInt(SQLITE_READONLY_RECOVERY);
+    DefInt(SQLITE_READONLY_CANTLOCK);
+    DefInt(SQLITE_READONLY_ROLLBACK);
+    DefInt(SQLITE_READONLY_DBMOVED);
+    DefInt(SQLITE_READONLY_CANTINIT);
+    DefInt(SQLITE_READONLY_DIRECTORY);
+    DefInt(SQLITE_ABORT_ROLLBACK);
+    DefInt(SQLITE_CONSTRAINT_CHECK);
+    DefInt(SQLITE_CONSTRAINT_COMMITHOOK);
+    DefInt(SQLITE_CONSTRAINT_FOREIGNKEY);
+    DefInt(SQLITE_CONSTRAINT_FUNCTION);
+    DefInt(SQLITE_CONSTRAINT_NOTNULL);
+    DefInt(SQLITE_CONSTRAINT_PRIMARYKEY);
+    DefInt(SQLITE_CONSTRAINT_TRIGGER);
+    DefInt(SQLITE_CONSTRAINT_UNIQUE);
+    DefInt(SQLITE_CONSTRAINT_VTAB);
+    DefInt(SQLITE_CONSTRAINT_ROWID);
+    DefInt(SQLITE_CONSTRAINT_PINNED);
+    DefInt(SQLITE_CONSTRAINT_DATATYPE);
+    DefInt(SQLITE_NOTICE_RECOVER_WAL);
+    DefInt(SQLITE_NOTICE_RECOVER_ROLLBACK);
+    DefInt(SQLITE_WARNING_AUTOINDEX);
+    DefInt(SQLITE_AUTH_USER);
+    DefInt(SQLITE_OK_LOAD_PERMANENTLY);
+    //DefInt(SQLITE_OK_SYMLINK) /* internal use only */;
+  } _DefGroup;
+
+  DefGroup(serialize){
+    DefInt(SQLITE_SERIALIZE_NOCOPY);
+    DefInt(SQLITE_DESERIALIZE_FREEONCLOSE);
+    DefInt(SQLITE_DESERIALIZE_READONLY);
+    DefInt(SQLITE_DESERIALIZE_RESIZEABLE);
+  } _DefGroup;
+
+  DefGroup(syncFlags) {
+    DefInt(SQLITE_SYNC_NORMAL);
+    DefInt(SQLITE_SYNC_FULL);
+    DefInt(SQLITE_SYNC_DATAONLY);
+  } _DefGroup;
+
+  DefGroup(trace) {
+    DefInt(SQLITE_TRACE_STMT);
+    DefInt(SQLITE_TRACE_PROFILE);
+    DefInt(SQLITE_TRACE_ROW);
+    DefInt(SQLITE_TRACE_CLOSE);
+  } _DefGroup;
+
+  DefGroup(udfFlags) {
+    DefInt(SQLITE_DETERMINISTIC);
+    DefInt(SQLITE_DIRECTONLY);
+    DefInt(SQLITE_INNOCUOUS);
+  } _DefGroup;
+
+  DefGroup(version) {
+    DefInt(SQLITE_VERSION_NUMBER);
+    DefStr(SQLITE_VERSION);
+    DefStr(SQLITE_SOURCE_ID);
+  } _DefGroup;
+  
+#undef DefGroup
+#undef DefStr
+#undef DefInt
+#undef _DefGroup
+
+  /*
+  ** Emit an array of "StructBinder" struct descripions, which look
+  ** like:
+  **
+  ** {
+  **   "name": "MyStruct",
+  **   "sizeof": 16,
+  **   "members": {
+  **     "member1": {"offset": 0,"sizeof": 4,"signature": "i"},
+  **     "member2": {"offset": 4,"sizeof": 4,"signature": "p"},
+  **     "member3": {"offset": 8,"sizeof": 8,"signature": "j"}
+  **   }
+  ** }
+  **
+  ** Detailed documentation for those bits are in the docs for the
+  ** Jaccwabyt JS-side component.
+  */
+
+  /** Macros for emitting StructBinder description. */
+#define StructBinder__(TYPE)                 \
+  n = 0;                                     \
+  outf("%s{", (nStruct++ ? ", " : ""));  \
+  out("\"name\": \"" # TYPE "\",");         \
+  outf("\"sizeof\": %d", (int)sizeof(TYPE)); \
+  out(",\"members\": {");
+#define StructBinder_(T) StructBinder__(T)
+  /** ^^^ indirection needed to expand CurrentStruct */
+#define StructBinder StructBinder_(CurrentStruct)
+#define _StructBinder CloseBrace(2)
+#define M(MEMBER,SIG)                                         \
+  outf("%s\"%s\": "                                           \
+       "{\"offset\":%d,\"sizeof\": %d,\"signature\":\"%s\"}", \
+       (n++ ? ", " : ""), #MEMBER,                            \
+       (int)offsetof(CurrentStruct,MEMBER),                   \
+       (int)sizeof(((CurrentStruct*)0)->MEMBER),              \
+       SIG)
+
+  nStruct = 0;
+  out(", \"structs\": ["); {
+
+#define CurrentStruct sqlite3_vfs
+    StructBinder {
+      M(iVersion,"i");
+      M(szOsFile,"i");
+      M(mxPathname,"i");
+      M(pNext,"p");
+      M(zName,"s");
+      M(pAppData,"p");
+      M(xOpen,"i(pppip)");
+      M(xDelete,"i(ppi)");
+      M(xAccess,"i(ppip)");
+      M(xFullPathname,"i(ppip)");
+      M(xDlOpen,"p(pp)");
+      M(xDlError,"p(pip)");
+      M(xDlSym,"p()");
+      M(xDlClose,"v(pp)");
+      M(xRandomness,"i(pip)");
+      M(xSleep,"i(pi)");
+      M(xCurrentTime,"i(pp)");
+      M(xGetLastError,"i(pip)");
+      M(xCurrentTimeInt64,"i(pp)");
+      M(xSetSystemCall,"i(ppp)");
+      M(xGetSystemCall,"p(pp)");
+      M(xNextSystemCall,"p(pp)");
+    } _StructBinder;
+#undef CurrentStruct
+
+#define CurrentStruct sqlite3_io_methods
+    StructBinder {
+      M(iVersion,"i");
+      M(xClose,"i(p)");
+      M(xRead,"i(ppij)");
+      M(xWrite,"i(ppij)");
+      M(xTruncate,"i(pj)");
+      M(xSync,"i(pi)");
+      M(xFileSize,"i(pp)");
+      M(xLock,"i(pi)");
+      M(xUnlock,"i(pi)");
+      M(xCheckReservedLock,"i(pp)");
+      M(xFileControl,"i(pip)");
+      M(xSectorSize,"i(p)");
+      M(xDeviceCharacteristics,"i(p)");
+      M(xShmMap,"i(piiip)");
+      M(xShmLock,"i(piii)");
+      M(xShmBarrier,"v(p)");
+      M(xShmUnmap,"i(pi)");
+      M(xFetch,"i(pjip)");
+      M(xUnfetch,"i(pjp)");
+    } _StructBinder;
+#undef CurrentStruct
+
+#define CurrentStruct sqlite3_file
+    StructBinder {
+      M(pMethods,"p");
+    } _StructBinder;
+#undef CurrentStruct
+
+#define CurrentStruct sqlite3_kvvfs_methods
+    StructBinder {
+      M(xRead,"i(sspi)");
+      M(xWrite,"i(sss)");
+      M(xDelete,"i(ss)");
+      M(nKeySize,"i");
+    } _StructBinder;
+#undef CurrentStruct
+
+#if SQLITE_WASM_TESTS
+#define CurrentStruct WasmTestStruct
+    StructBinder {
+      M(v4,"i");
+      M(cstr,"s");
+      M(ppV,"p");
+      M(v8,"j");
+      M(xFunc,"v(p)");
+    } _StructBinder;
+#undef CurrentStruct
+#endif
+
+  } out( "]"/*structs*/);
+
+  out("}"/*top-level object*/);
+  *zPos = 0;
+  aBuffer[0] = '{'/*end of the race-condition workaround*/;
+  return aBuffer;
+#undef StructBinder
+#undef StructBinder_
+#undef StructBinder__
+#undef M
+#undef _StructBinder
+#undef CloseBrace
+#undef out
+#undef outf
+#undef lenCheck
+}
+
+/*
+** This function is NOT part of the sqlite3 public API. It is strictly
+** for use by the sqlite project's own JS/WASM bindings.
+**
+** This function invokes the xDelete method of the given VFS (or the
+** default VFS if pVfs is NULL), passing on the given filename. If
+** zName is NULL, no default VFS is found, or it has no xDelete
+** method, SQLITE_MISUSE is returned, else the result of the xDelete()
+** call is returned.
+*/
+SQLITE_WASM_KEEP
+int sqlite3_wasm_vfs_unlink(sqlite3_vfs *pVfs, const char * zName){
+  int rc = SQLITE_MISUSE /* ??? */;
+  if( 0==pVfs && 0!=zName ) pVfs = sqlite3_vfs_find(0);
+  if( zName && pVfs && pVfs->xDelete ){
+    rc = pVfs->xDelete(pVfs, zName, 1);
+  }
+  return rc;
+}
+
+/*
+** This function is NOT part of the sqlite3 public API. It is strictly
+** for use by the sqlite project's own JS/WASM bindings.
+**
+** Returns a pointer to the given DB's VFS for the given DB name,
+** defaulting to "main" if zDbName is 0. Returns 0 if no db with the
+** given name is open.
+*/
+SQLITE_WASM_KEEP
+sqlite3_vfs * sqlite3_wasm_db_vfs(sqlite3 *pDb, const char *zDbName){
+  sqlite3_vfs * pVfs = 0;
+  sqlite3_file_control(pDb, zDbName ? zDbName : "main",
+                       SQLITE_FCNTL_VFS_POINTER, &pVfs);
+  return pVfs;
+}
+
+/*
+** This function is NOT part of the sqlite3 public API. It is strictly
+** for use by the sqlite project's own JS/WASM bindings.
+**
+** This function resets the given db pointer's database as described at
+**
+** https://www.sqlite.org/c3ref/c_dbconfig_defensive.html#sqlitedbconfigresetdatabase
+**
+** Returns 0 on success, an SQLITE_xxx code on error. Returns
+** SQLITE_MISUSE if pDb is NULL.
+*/
+SQLITE_WASM_KEEP
+int sqlite3_wasm_db_reset(sqlite3*pDb){
+  int rc = SQLITE_MISUSE;
+  if( pDb ){
+    rc = sqlite3_db_config(pDb, SQLITE_DBCONFIG_RESET_DATABASE, 1, 0);
+    if( 0==rc ) rc = sqlite3_exec(pDb, "VACUUM", 0, 0, 0);
+    sqlite3_db_config(pDb, SQLITE_DBCONFIG_RESET_DATABASE, 0, 0);
+  }
+  return rc;
+}
+
+/*
+** Uses the given database's VFS xRead to stream the db file's
+** contents out to the given callback. The callback gets a single
+** chunk of size n (its 2nd argument) on each call and must return 0
+** on success, non-0 on error. This function returns 0 on success,
+** SQLITE_NOTFOUND if no db is open, or propagates any other non-0
+** code from the callback. Note that this is not thread-friendly: it
+** expects that it will be the only thread reading the db file and
+** takes no measures to ensure that is the case.
+**
+** This implementation appears to work fine, but
+** sqlite3_wasm_db_serialize() is arguably the better way to achieve
+** this.
+*/
+SQLITE_WASM_KEEP
+int sqlite3_wasm_db_export_chunked( sqlite3* pDb,
+                                    int (*xCallback)(unsigned const char *zOut, int n) ){
+  sqlite3_int64 nSize = 0;
+  sqlite3_int64 nPos = 0;
+  sqlite3_file * pFile = 0;
+  unsigned char buf[1024 * 8];
+  int nBuf = (int)sizeof(buf);
+  int rc = pDb
+    ? sqlite3_file_control(pDb, "main",
+                           SQLITE_FCNTL_FILE_POINTER, &pFile)
+    : SQLITE_NOTFOUND;
+  if( rc ) return rc;
+  rc = pFile->pMethods->xFileSize(pFile, &nSize);
+  if( rc ) return rc;
+  if(nSize % nBuf){
+    /* DB size is not an even multiple of the buffer size. Reduce
+    ** buffer size so that we do not unduly inflate the db size
+    ** with zero-padding when exporting. */
+    if(0 == nSize % 4096) nBuf = 4096;
+    else if(0 == nSize % 2048) nBuf = 2048;
+    else if(0 == nSize % 1024) nBuf = 1024;
+    else nBuf = 512;
+  }
+  for( ; 0==rc && nPos<nSize; nPos += nBuf ){
+    rc = pFile->pMethods->xRead(pFile, buf, nBuf, nPos);
+    if(SQLITE_IOERR_SHORT_READ == rc){
+      rc = (nPos + nBuf) < nSize ? rc : 0/*assume EOF*/;
+    }
+    if( 0==rc ) rc = xCallback(buf, nBuf);
+  }
+  return rc;
+}
+
+/*
+** A proxy for sqlite3_serialize() which serializes the "main" schema
+** of pDb, placing the serialized output in pOut and nOut. nOut may be
+** NULL. If pDb or pOut are NULL then SQLITE_MISUSE is returned. If
+** allocation of the serialized copy fails, SQLITE_NOMEM is returned.
+** On success, 0 is returned and `*pOut` will contain a pointer to the
+** memory unless mFlags includes SQLITE_SERIALIZE_NOCOPY and the
+** database has no contiguous memory representation, in which case
+** `*pOut` will be NULL but 0 will be returned.
+**
+** If `*pOut` is not NULL, the caller is responsible for passing it to
+** sqlite3_free() to free it.
+*/
+SQLITE_WASM_KEEP
+int sqlite3_wasm_db_serialize( sqlite3 *pDb, unsigned char **pOut,
+                               sqlite3_int64 *nOut, unsigned int mFlags ){
+  unsigned char * z;
+  if( !pDb || !pOut ) return SQLITE_MISUSE;
+  if(nOut) *nOut = 0;
+  z = sqlite3_serialize(pDb, "main", nOut, mFlags);
+  if( z || (SQLITE_SERIALIZE_NOCOPY & mFlags) ){
+    *pOut = z;
+    return 0;
+  }else{
+    return SQLITE_NOMEM;
+  }
+}
+
+/*
+** This function is NOT part of the sqlite3 public API. It is strictly
+** for use by the sqlite project's own JS/WASM bindings.
+**
+** Creates a new file using the I/O API of the given VFS, containing
+** the given number of bytes of the given data. If the file exists,
+** it is truncated to the given length and populated with the given
+** data.
+**
+** This function exists so that we can implement the equivalent of
+** Emscripten's FS.createDataFile() in a VFS-agnostic way. This
+** functionality is intended for use in uploading database files.
+**
+** If pVfs is NULL, sqlite3_vfs_find(0) is used.
+**
+** If zFile is NULL, pVfs is NULL (and sqlite3_vfs_find(0) returns
+** NULL), or nData is negative, SQLITE_MISUSE are returned.
+**
+** On success, it creates a new file with the given name, populated
+** with the fist nData bytes of pData. If pData is NULL, the file is
+** created and/or truncated to nData bytes.
+**
+** Whether or not directory components of zFilename are created
+** automatically or not is unspecified: that detail is left to the
+** VFS. The "opfs" VFS, for example, create them.
+**
+** Not all VFSes support this functionality, e.g. the "kvvfs" does
+** not.
+**
+** If an error happens while populating or truncating the file, the
+** target file will be deleted (if needed) if this function created
+** it. If this function did not create it, it is not deleted but may
+** be left in an undefined state.
+**
+** Returns 0 on success. On error, it returns a code described above
+** or propagates a code from one of the I/O methods.
+**
+** Design note: nData is an integer, instead of int64, for WASM
+** portability, so that the API can still work in builds where BigInt
+** support is disabled or unavailable.
+*/
+SQLITE_WASM_KEEP
+int sqlite3_wasm_vfs_create_file( sqlite3_vfs *pVfs,
+                                  const char *zFilename,
+                                  const unsigned char * pData,
+                                  int nData ){
+  int rc;
+  sqlite3_file *pFile = 0;
+  sqlite3_io_methods const *pIo;
+  const int openFlags = SQLITE_OPEN_READWRITE | SQLITE_OPEN_CREATE;
+  int flagsOut = 0;
+  int fileExisted = 0;
+  int doUnlock = 0;
+  const unsigned char *pPos = pData;
+  const int blockSize = 512
+    /* Because we are using pFile->pMethods->xWrite() for writing, and
+    ** it may have a buffer limit related to sqlite3's pager size, we
+    ** conservatively write in 512-byte blocks (smallest page
+    ** size). */;
+
+  if( !pVfs ) pVfs = sqlite3_vfs_find(0);
+  if( !pVfs || !zFilename || nData<0 ) return SQLITE_MISUSE;
+  pVfs->xAccess(pVfs, zFilename, SQLITE_ACCESS_EXISTS, &fileExisted);
+  rc = sqlite3OsOpenMalloc(pVfs, zFilename, &pFile, openFlags, &flagsOut);
+  if(rc) return rc;
+  pIo = pFile->pMethods;
+  if( pIo->xLock ) {
+    /* We need xLock() in order to accommodate the OPFS VFS, as it
+    ** obtains a writeable handle via the lock operation and releases
+    ** it in xUnlock(). If we don't do those here, we have to add code
+    ** to the VFS to account check whether it was locked before
+    ** xFileSize(), xTruncate(), and the like, and release the lock
+    ** only if it was unlocked when the op was started. */
+    rc = pIo->xLock(pFile, SQLITE_LOCK_EXCLUSIVE);
+    doUnlock = 0==rc;
+  }
+  if( 0==rc) rc = pIo->xTruncate(pFile, nData);
+  if( 0==rc && 0!=pData && nData>0 ){
+    while( 0==rc && nData>0 ){
+      const int n = nData>=blockSize ? blockSize : nData;
+      rc = pIo->xWrite(pFile, pPos, n, (sqlite3_int64)(pPos - pData));
+      nData -= n;
+      pPos += n;
+    }
+    if( 0==rc && nData>0 ){
+      assert( nData<blockSize );
+      rc = pIo->xWrite(pFile, pPos, nData, (sqlite3_int64)(pPos - pData));
+    }
+  }
+  if( pIo->xUnlock && doUnlock!=0 ) pIo->xUnlock(pFile, SQLITE_LOCK_NONE);
+  pIo->xClose(pFile);
+  if( rc!=0 && 0==fileExisted ){
+    pVfs->xDelete(pVfs, zFilename, 1);
+  }
+  return rc;
+}
+
+/*
+** This function is NOT part of the sqlite3 public API. It is strictly
+** for use by the sqlite project's own JS/WASM bindings.
+**
+** Allocates sqlite3KvvfsMethods.nKeySize bytes from
+** sqlite3_wasm_pstack_alloc() and returns 0 if that allocation fails,
+** else it passes that string to kvstorageMakeKey() and returns a
+** NUL-terminated pointer to that string. It is up to the caller to
+** use sqlite3_wasm_pstack_restore() to free the returned pointer.
+*/
+SQLITE_WASM_KEEP
+char * sqlite3_wasm_kvvfsMakeKeyOnPstack(const char *zClass,
+                                         const char *zKeyIn){
+  assert(sqlite3KvvfsMethods.nKeySize>24);
+  char *zKeyOut =
+    (char *)sqlite3_wasm_pstack_alloc(sqlite3KvvfsMethods.nKeySize);
+  if(zKeyOut){
+    kvstorageMakeKey(zClass, zKeyIn, zKeyOut);
+  }
+  return zKeyOut;
+}
+
+/*
+** This function is NOT part of the sqlite3 public API. It is strictly
+** for use by the sqlite project's own JS/WASM bindings.
+**
+** Returns the pointer to the singleton object which holds the kvvfs
+** I/O methods and associated state.
+*/
+SQLITE_WASM_KEEP
+sqlite3_kvvfs_methods * sqlite3_wasm_kvvfs_methods(void){
+  return &sqlite3KvvfsMethods;
+}
+
+#if defined(__EMSCRIPTEN__) && defined(SQLITE_ENABLE_WASMFS)
+#include <emscripten/wasmfs.h>
+
+/*
+** This function is NOT part of the sqlite3 public API. It is strictly
+** for use by the sqlite project's own JS/WASM bindings, specifically
+** only when building with Emscripten's WASMFS support.
+**
+** This function should only be called if the JS side detects the
+** existence of the Origin-Private FileSystem (OPFS) APIs in the
+** client. The first time it is called, this function instantiates a
+** WASMFS backend impl for OPFS. On success, subsequent calls are
+** no-ops.
+**
+** This function may be passed a "mount point" name, which must have a
+** leading "/" and is currently restricted to a single path component,
+** e.g. "/foo" is legal but "/foo/" and "/foo/bar" are not. If it is
+** NULL or empty, it defaults to "/opfs".
+**
+** Returns 0 on success, SQLITE_NOMEM if instantiation of the backend
+** object fails, SQLITE_IOERR if mkdir() of the zMountPoint dir in
+** the virtual FS fails. In builds compiled without SQLITE_ENABLE_WASMFS
+** defined, SQLITE_NOTFOUND is returned without side effects.
+*/
+SQLITE_WASM_KEEP
+int sqlite3_wasm_init_wasmfs(const char *zMountPoint){
+  static backend_t pOpfs = 0;
+  if( !zMountPoint || !*zMountPoint ) zMountPoint = "/opfs";
+  if( !pOpfs ){
+    pOpfs = wasmfs_create_opfs_backend();
+  }
+  /** It's not enough to instantiate the backend. We have to create a
+      mountpoint in the VFS and attach the backend to it. */
+  if( pOpfs && 0!=access(zMountPoint, F_OK) ){
+    /* Note that this check and is not robust but it will
+       hypothetically suffice for the transient wasm-based virtual
+       filesystem we're currently running in. */
+    const int rc = wasmfs_create_directory(zMountPoint, 0777, pOpfs);
+    /*emscripten_console_logf("OPFS mkdir(%s) rc=%d", zMountPoint, rc);*/
+    if(rc) return SQLITE_IOERR;
+  }
+  return pOpfs ? 0 : SQLITE_NOMEM;
+}
+#else
+SQLITE_WASM_KEEP
+int sqlite3_wasm_init_wasmfs(const char *zUnused){
+  //emscripten_console_warn("WASMFS OPFS is not compiled in.");
+  if(zUnused){/*unused*/}
+  return SQLITE_NOTFOUND;
+}
+#endif /* __EMSCRIPTEN__ && SQLITE_ENABLE_WASMFS */
+
+#if SQLITE_WASM_TESTS
+
+SQLITE_WASM_KEEP
+int sqlite3_wasm_test_intptr(int * p){
+  return *p = *p * 2;
+}
+
+SQLITE_WASM_KEEP
+int64_t sqlite3_wasm_test_int64_max(void){
+  return (int64_t)0x7fffffffffffffff;
+}
+
+SQLITE_WASM_KEEP
+int64_t sqlite3_wasm_test_int64_min(void){
+  return ~sqlite3_wasm_test_int64_max();
+}
+
+SQLITE_WASM_KEEP
+int64_t sqlite3_wasm_test_int64_times2(int64_t x){
+  return x * 2;
+}
+
+SQLITE_WASM_KEEP
+void sqlite3_wasm_test_int64_minmax(int64_t * min, int64_t *max){
+  *max = sqlite3_wasm_test_int64_max();
+  *min = sqlite3_wasm_test_int64_min();
+  /*printf("minmax: min=%lld, max=%lld\n", *min, *max);*/
+}
+
+SQLITE_WASM_KEEP
+int64_t sqlite3_wasm_test_int64ptr(int64_t * p){
+  /*printf("sqlite3_wasm_test_int64ptr( @%lld = 0x%llx )\n", (int64_t)p, *p);*/
+  return *p = *p * 2;
+}
+
+SQLITE_WASM_KEEP
+void sqlite3_wasm_test_stack_overflow(int recurse){
+  if(recurse) sqlite3_wasm_test_stack_overflow(recurse);
+}
+
+/* For testing the 'string-free' whwasmutil.xWrap() conversion. */
+SQLITE_WASM_KEEP
+char * sqlite3_wasm_test_str_hello(int fail){
+  char * s = fail ? 0 : (char *)malloc(6);
+  if(s){
+    memcpy(s, "hello", 5);
+    s[5] = 0;
+  }
+  return s;
+}
+#endif /* SQLITE_WASM_TESTS */
+
+#undef SQLITE_WASM_KEEP