From 9885c76c4c86f4de670ce8b762c4df2ce1e99007 Mon Sep 17 00:00:00 2001
From: stephan <stephan@noemail.net>
Date: Mon, 27 Feb 2023 07:12:28 +0000
Subject: [PATCH] Extend wasm build to enable inclusion of client-custom C
 code, initialized via the SQLITE_EXTRA_INIT mechanism, per discussion in
 [forum:1e1c04f3ed1bc96b|forum post 1e1c04f3ed1bc96b].

FossilOrigin-Name: 68a52cafff60f19c9c998133d04f192b1e8b23f78b8cee13807d76845ef5e13d
---
 ext/wasm/GNUmakefile          | 35 ++++++++++++--
 ext/wasm/api/sqlite3-wasm.c   | 90 ++++++++++++++++++-----------------
 ext/wasm/example_extra_init.c | 22 +++++++++
 ext/wasm/fiddle.make          |  2 +-
 manifest                      | 19 ++++----
 manifest.uuid                 |  2 +-
 6 files changed, 113 insertions(+), 57 deletions(-)
 create mode 100644 ext/wasm/example_extra_init.c

diff --git a/ext/wasm/GNUmakefile b/ext/wasm/GNUmakefile
index 20dab446da..f2d6ae9f0b 100644
--- a/ext/wasm/GNUmakefile
+++ b/ext/wasm/GNUmakefile
@@ -189,6 +189,34 @@ else
   $(info Development build. Use '$(MAKE) release' for a smaller release build.)
 endif
 
+########################################################################
+# Adding custom C code via sqlite3_wasm_extra_init.c:
+#
+# If the canonical build process finds the file
+# sqlite3_wasm_extra_init.c in the main wasm build directory, it
+# arranges to include that file in the build of sqlite3.wasm and
+# defines SQLITE_EXTRA_INIT=sqlite3_wasm_extra_init.
+#
+# sqlite3_wasm_extra_init() must be a function with this signature:
+#
+#  int sqlite3_wasm_extra_init(const char *)
+#
+# and the sqlite3 library will call it with an argument of NULL one
+# time during sqlite3_initialize(). If it returns non-0,
+# initialization of the library will fail.
+#
+# The filename can be overridden with:
+#
+#  make sqlite3_wasm_extra_init.c=my_custom_stuff.c
+#
+# See example_extra_init.c for an example implementation.
+########################################################################
+sqlite3_wasm_extra_init.c ?= $(wildcard sqlite3_wasm_extra_init.c)
+ifneq (,$(sqlite3_wasm_extra_init.c))
+  $(info Enabling SQLITE_EXTRA_INIT via $(sqlite3_wasm_extra_init.c).)
+  SQLITE_OPT += -I. -DSQLITE_WASM_EXTRA_INIT
+endif
+
 # bin.version-info = binary to output various sqlite3 version info for
 # embedding in the JS files and in building the distribution zip file.
 # It must NOT be in $(dir.tmp) because we need it to survive the
@@ -576,6 +604,7 @@ endef
 # https://github.com/emscripten-core/emscripten/issues/14383
 sqlite3.wasm := $(dir.dout)/sqlite3.wasm
 sqlite3-wasm.c := $(dir.api)/sqlite3-wasm.c
+sqlite3-wasm.cs := $(sqlite3-wasm.c) $(sqlite3_wasm_extra_init.c)
 # sqlite3-wasm.o vs sqlite3-wasm.c: building against the latter
 # (predictably) results in a slightly faster binary. We're close
 # enough to the target speed requirements that the 500ms makes a
@@ -650,12 +679,12 @@ $$(eval $$(call call-make-pre-post,sqlite3,$(1)))
 emcc.flags.sqlite3.$(1) := $(6)
 $$(eval $$(call C-PP.FILTER, $$(sqlite3-api.js.in), $(3), $(5)))
 $(4): $(3)
-$(4): $(3) $$(MAKEFILE) $$(sqlite3-wasm.c) $$(EXPORTED_FUNCTIONS.api) $$(pre-post-sqlite3.deps.$(1))
+$(4): $(3) $$(MAKEFILE) $$(sqlite3-wasm.cs) $$(EXPORTED_FUNCTIONS.api) $$(pre-post-sqlite3.deps.$(1))
 	@echo "Building $$@ ..."
 	$$(emcc.bin) -o $$@ $$(emcc_opt_full) $$(emcc.flags) \
     $$(emcc.jsflags) \
     $$(pre-post-sqlite3.flags.$(1)) $$(emcc.flags.sqlite3.$(1)) \
-    $$(cflags.common) $$(SQLITE_OPT) $$(sqlite3-wasm.c)
+    $$(cflags.common) $$(SQLITE_OPT) $$(sqlite3-wasm.cs)
 	@$$(call SQLITE3.xJS.ESM-EXPORT-DEFAULT,$(2))
 	@if [ bundler-friendly = $(1) ]; then \
 		echo "Patching $(3) for sqlite3.wasm..."; \
@@ -806,7 +835,7 @@ $(EXPORTED_FUNCTIONS.speedtest1): $(EXPORTED_FUNCTIONS.api)
 speedtest1.js := $(dir.dout)/speedtest1.js
 speedtest1.wasm := $(dir.dout)/speedtest1.wasm
 cflags.speedtest1 := $(cflags.common) -DSQLITE_SPEEDTEST1_WASM
-speedtest1.cses := $(speedtest1.c) $(sqlite3-wasm.c)
+speedtest1.cses := $(speedtest1.c) $(sqlite3-wasm.cs)
 $(eval $(call call-make-pre-post,speedtest1,vanilla))
 $(speedtest1.js): $(MAKEFILE) $(speedtest1.cses) \
     $(pre-post-speedtest1.deps.vanilla) \
diff --git a/ext/wasm/api/sqlite3-wasm.c b/ext/wasm/api/sqlite3-wasm.c
index e7513509ca..bcabe922bf 100644
--- a/ext/wasm/api/sqlite3-wasm.c
+++ b/ext/wasm/api/sqlite3-wasm.c
@@ -163,6 +163,10 @@
 #  define SQLITE_USE_URI 1
 #endif
 
+#ifdef SQLITE_WASM_EXTRA_INIT
+#  define SQLITE_EXTRA_INIT sqlite3_wasm_extra_init
+#endif
+
 #include <assert.h>
 #include "sqlite3.c" /* yes, .c instead of .h. */
 
@@ -171,7 +175,7 @@
 #endif
 
 /*
-** SQLITE_WASM_KEEP is functionally identical to EMSCRIPTEN_KEEPALIVE
+** SQLITE_WASM_EXPORT 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
@@ -193,7 +197,7 @@
 ** 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")))
+#define SQLITE_WASM_EXPORT __attribute__((used,visibility("default")))
 // See also:
 //__attribute__((export_name("theExportedName"), used, visibility("default")))
 
@@ -210,24 +214,24 @@
 ** Another option is to malloc() a chunk of our own and call that our
 ** "stack".
 */
-SQLITE_WASM_KEEP void * sqlite3_wasm_stack_end(void){
+SQLITE_WASM_EXPORT 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){
+SQLITE_WASM_EXPORT 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){
+SQLITE_WASM_EXPORT 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){
+SQLITE_WASM_EXPORT void sqlite3_wasm_stack_restore(void * p){
   pWasmStackPtr = p;
 }
-SQLITE_WASM_KEEP void * sqlite3_wasm_stack_alloc(int n){
+SQLITE_WASM_EXPORT 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();
@@ -263,14 +267,14 @@ static struct {
 /*
 ** Returns the current pstack position.
 */
-SQLITE_WASM_KEEP void * sqlite3_wasm_pstack_ptr(void){
+SQLITE_WASM_EXPORT 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){
+SQLITE_WASM_EXPORT 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*/){
@@ -285,7 +289,7 @@ SQLITE_WASM_KEEP void sqlite3_wasm_pstack_restore(unsigned char * p){
 ** 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){
+SQLITE_WASM_EXPORT 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 */;
@@ -298,7 +302,7 @@ SQLITE_WASM_KEEP void * sqlite3_wasm_pstack_alloc(int n){
 ** Return the number of bytes left which can be
 ** sqlite3_wasm_pstack_alloc()'d.
 */
-SQLITE_WASM_KEEP int sqlite3_wasm_pstack_remaining(void){
+SQLITE_WASM_EXPORT int sqlite3_wasm_pstack_remaining(void){
   assert(PStack.pPos >= PStack.pBegin);
   assert(PStack.pPos <= PStack.pEnd);
   return (int)(PStack.pPos - PStack.pBegin);
@@ -309,7 +313,7 @@ SQLITE_WASM_KEEP int sqlite3_wasm_pstack_remaining(void){
 ** any space which is currently allocated. This value is a
 ** compile-time constant.
 */
-SQLITE_WASM_KEEP int sqlite3_wasm_pstack_quota(void){
+SQLITE_WASM_EXPORT int sqlite3_wasm_pstack_quota(void){
   return (int)(PStack.pEnd - PStack.pBegin);
 }
 
@@ -327,7 +331,7 @@ SQLITE_WASM_KEEP int sqlite3_wasm_pstack_quota(void){
 **
 ** Returns err_code.
 */
-SQLITE_WASM_KEEP
+SQLITE_WASM_EXPORT
 int sqlite3_wasm_db_error(sqlite3*db, int err_code, const char *zMsg){
   if( db!=0 ){
     if( 0!=zMsg ){
@@ -349,7 +353,7 @@ struct WasmTestStruct {
   void (*xFunc)(void*);
 };
 typedef struct WasmTestStruct WasmTestStruct;
-SQLITE_WASM_KEEP
+SQLITE_WASM_EXPORT
 void sqlite3_wasm_test_struct(WasmTestStruct * s){
   if(s){
     s->v4 *= 2;
@@ -377,7 +381,7 @@ void sqlite3_wasm_test_struct(WasmTestStruct * s){
 ** 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
+SQLITE_WASM_EXPORT
 const char * sqlite3_wasm_enum_json(void){
   static char aBuffer[1024 * 20] = {0} /* where the JSON goes */;
   int n = 0, nChildren = 0, nStruct = 0
@@ -1182,7 +1186,7 @@ const char * sqlite3_wasm_enum_json(void){
 ** method, SQLITE_MISUSE is returned, else the result of the xDelete()
 ** call is returned.
 */
-SQLITE_WASM_KEEP
+SQLITE_WASM_EXPORT
 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);
@@ -1200,7 +1204,7 @@ int sqlite3_wasm_vfs_unlink(sqlite3_vfs *pVfs, const char *zName){
 ** defaulting to "main" if zDbName is 0. Returns 0 if no db with the
 ** given name is open.
 */
-SQLITE_WASM_KEEP
+SQLITE_WASM_EXPORT
 sqlite3_vfs * sqlite3_wasm_db_vfs(sqlite3 *pDb, const char *zDbName){
   sqlite3_vfs * pVfs = 0;
   sqlite3_file_control(pDb, zDbName ? zDbName : "main",
@@ -1223,7 +1227,7 @@ sqlite3_vfs * sqlite3_wasm_db_vfs(sqlite3 *pDb, const char *zDbName){
 ** Returns 0 on success, an SQLITE_xxx code on error. Returns
 ** SQLITE_MISUSE if pDb is NULL.
 */
-SQLITE_WASM_KEEP
+SQLITE_WASM_EXPORT
 int sqlite3_wasm_db_reset(sqlite3 *pDb){
   int rc = SQLITE_MISUSE;
   if( pDb ){
@@ -1254,7 +1258,7 @@ int sqlite3_wasm_db_reset(sqlite3 *pDb){
 ** sqlite3_wasm_db_serialize() is arguably the better way to achieve
 ** this.
 */
-SQLITE_WASM_KEEP
+SQLITE_WASM_EXPORT
 int sqlite3_wasm_db_export_chunked( sqlite3* pDb,
                                     int (*xCallback)(unsigned const char *zOut, int n) ){
   sqlite3_int64 nSize = 0;
@@ -1305,7 +1309,7 @@ int sqlite3_wasm_db_export_chunked( sqlite3* pDb,
 ** If `*pOut` is not NULL, the caller is responsible for passing it to
 ** sqlite3_free() to free it.
 */
-SQLITE_WASM_KEEP
+SQLITE_WASM_EXPORT
 int sqlite3_wasm_db_serialize( sqlite3 *pDb, const char *zSchema,
                                unsigned char **pOut,
                                sqlite3_int64 *nOut, unsigned int mFlags ){
@@ -1362,7 +1366,7 @@ int sqlite3_wasm_db_serialize( sqlite3 *pDb, const char *zSchema,
 ** portability, so that the API can still work in builds where BigInt
 ** support is disabled or unavailable.
 */
-SQLITE_WASM_KEEP
+SQLITE_WASM_EXPORT
 int sqlite3_wasm_vfs_create_file( sqlite3_vfs *pVfs,
                                   const char *zFilename,
                                   const unsigned char * pData,
@@ -1446,7 +1450,7 @@ int sqlite3_wasm_vfs_create_file( sqlite3_vfs *pVfs,
 ** 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
+SQLITE_WASM_EXPORT
 char * sqlite3_wasm_kvvfsMakeKeyOnPstack(const char *zClass,
                                          const char *zKeyIn){
   assert(sqlite3KvvfsMethods.nKeySize>24);
@@ -1465,7 +1469,7 @@ char * sqlite3_wasm_kvvfsMakeKeyOnPstack(const char *zClass,
 ** Returns the pointer to the singleton object which holds the kvvfs
 ** I/O methods and associated state.
 */
-SQLITE_WASM_KEEP
+SQLITE_WASM_EXPORT
 sqlite3_kvvfs_methods * sqlite3_wasm_kvvfs_methods(void){
   return &sqlite3KvvfsMethods;
 }
@@ -1480,7 +1484,7 @@ sqlite3_kvvfs_methods * sqlite3_wasm_kvvfs_methods(void){
 ** sqlite3_vtab_config(), or SQLITE_MISUSE if the 2nd arg is not a
 ** valid value.
 */
-SQLITE_WASM_KEEP
+SQLITE_WASM_EXPORT
 int sqlite3_wasm_vtab_config(sqlite3 *pDb, int op, int arg){
   switch(op){
   case SQLITE_VTAB_DIRECTONLY:
@@ -1500,7 +1504,7 @@ int sqlite3_wasm_vtab_config(sqlite3 *pDb, int op, int arg){
 ** Wrapper for the variants of sqlite3_db_config() which take
 ** (int,int*) variadic args.
 */
-SQLITE_WASM_KEEP
+SQLITE_WASM_EXPORT
 int sqlite3_wasm_db_config_ip(sqlite3 *pDb, int op, int arg1, int* pArg2){
   switch(op){
     case SQLITE_DBCONFIG_ENABLE_FKEY:
@@ -1531,7 +1535,7 @@ int sqlite3_wasm_db_config_ip(sqlite3 *pDb, int op, int arg1, int* pArg2){
 ** Wrapper for the variants of sqlite3_db_config() which take
 ** (void*,int,int) variadic args.
 */
-SQLITE_WASM_KEEP
+SQLITE_WASM_EXPORT
 int sqlite3_wasm_db_config_pii(sqlite3 *pDb, int op, void * pArg1, int arg2, int arg3){
   switch(op){
     case SQLITE_DBCONFIG_LOOKASIDE:
@@ -1547,7 +1551,7 @@ int sqlite3_wasm_db_config_pii(sqlite3 *pDb, int op, void * pArg1, int arg2, int
 ** Wrapper for the variants of sqlite3_db_config() which take
 ** (const char *) variadic args.
 */
-SQLITE_WASM_KEEP
+SQLITE_WASM_EXPORT
 int sqlite3_wasm_db_config_s(sqlite3 *pDb, int op, const char *zArg){
   switch(op){
     case SQLITE_DBCONFIG_MAINDBNAME:
@@ -1564,7 +1568,7 @@ int sqlite3_wasm_db_config_s(sqlite3 *pDb, int op, const char *zArg){
 ** Binding for combinations of sqlite3_config() arguments which take
 ** a single integer argument.
 */
-SQLITE_WASM_KEEP
+SQLITE_WASM_EXPORT
 int sqlite3_wasm_config_i(int op, int arg){
   return sqlite3_config(op, arg);
 }
@@ -1576,7 +1580,7 @@ int sqlite3_wasm_config_i(int op, int arg){
 ** Binding for combinations of sqlite3_config() arguments which take
 ** two int arguments.
 */
-SQLITE_WASM_KEEP
+SQLITE_WASM_EXPORT
 int sqlite3_wasm_config_ii(int op, int arg1, int arg2){
   return sqlite3_config(op, arg1, arg2);
 }
@@ -1588,7 +1592,7 @@ int sqlite3_wasm_config_ii(int op, int arg1, int arg2){
 ** Binding for combinations of sqlite3_config() arguments which take
 ** a single i64 argument.
 */
-SQLITE_WASM_KEEP
+SQLITE_WASM_EXPORT
 int sqlite3_wasm_config_j(int op, sqlite3_int64 arg){
   return sqlite3_config(op, arg);
 }
@@ -1617,7 +1621,7 @@ int sqlite3_wasm_config_j(int op, sqlite3_int64 arg){
 ** Safari-specific quirk covered at
 ** https://sqlite.org/forum/info/e5b20e1feb37a19a.
 **/
-SQLITE_WASM_KEEP
+SQLITE_WASM_EXPORT
 void * sqlite3_wasm_ptr_to_sqlite3_free(void){
   return (void*)sqlite3_free;
 }
@@ -1647,7 +1651,7 @@ void * sqlite3_wasm_ptr_to_sqlite3_free(void){
 ** the virtual FS fails. In builds compiled without SQLITE_ENABLE_WASMFS
 ** defined, SQLITE_NOTFOUND is returned without side effects.
 */
-SQLITE_WASM_KEEP
+SQLITE_WASM_EXPORT
 int sqlite3_wasm_init_wasmfs(const char *zMountPoint){
   static backend_t pOpfs = 0;
   if( !zMountPoint || !*zMountPoint ) zMountPoint = "/opfs";
@@ -1667,7 +1671,7 @@ int sqlite3_wasm_init_wasmfs(const char *zMountPoint){
   return pOpfs ? 0 : SQLITE_NOMEM;
 }
 #else
-SQLITE_WASM_KEEP
+SQLITE_WASM_EXPORT
 int sqlite3_wasm_init_wasmfs(const char *zUnused){
   //emscripten_console_warn("WASMFS OPFS is not compiled in.");
   if(zUnused){/*unused*/}
@@ -1677,51 +1681,51 @@ int sqlite3_wasm_init_wasmfs(const char *zUnused){
 
 #if SQLITE_WASM_TESTS
 
-SQLITE_WASM_KEEP
+SQLITE_WASM_EXPORT
 int sqlite3_wasm_test_intptr(int * p){
   return *p = *p * 2;
 }
 
-SQLITE_WASM_KEEP
+SQLITE_WASM_EXPORT
 void * sqlite3_wasm_test_voidptr(void * p){
   return p;
 }
 
-SQLITE_WASM_KEEP
+SQLITE_WASM_EXPORT
 int64_t sqlite3_wasm_test_int64_max(void){
   return (int64_t)0x7fffffffffffffff;
 }
 
-SQLITE_WASM_KEEP
+SQLITE_WASM_EXPORT
 int64_t sqlite3_wasm_test_int64_min(void){
   return ~sqlite3_wasm_test_int64_max();
 }
 
-SQLITE_WASM_KEEP
+SQLITE_WASM_EXPORT
 int64_t sqlite3_wasm_test_int64_times2(int64_t x){
   return x * 2;
 }
 
-SQLITE_WASM_KEEP
+SQLITE_WASM_EXPORT
 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
+SQLITE_WASM_EXPORT
 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
+SQLITE_WASM_EXPORT
 void sqlite3_wasm_test_stack_overflow(int recurse){
   if(recurse) sqlite3_wasm_test_stack_overflow(recurse);
 }
 
 /* For testing the 'string:dealloc' whwasmutil.xWrap() conversion. */
-SQLITE_WASM_KEEP
+SQLITE_WASM_EXPORT
 char * sqlite3_wasm_test_str_hello(int fail){
   char * s = fail ? 0 : (char *)sqlite3_malloc(6);
   if(s){
@@ -1732,4 +1736,4 @@ char * sqlite3_wasm_test_str_hello(int fail){
 }
 #endif /* SQLITE_WASM_TESTS */
 
-#undef SQLITE_WASM_KEEP
+#undef SQLITE_WASM_EXPORT
diff --git a/ext/wasm/example_extra_init.c b/ext/wasm/example_extra_init.c
new file mode 100644
index 0000000000..ca70386318
--- /dev/null
+++ b/ext/wasm/example_extra_init.c
@@ -0,0 +1,22 @@
+/*
+** If the canonical build process finds the file
+** sqlite3_wasm_extra_init.c in the main wasm build directory, it
+** arranges to include that file in the build of sqlite3.wasm and
+** defines SQLITE_EXTRA_INIT=sqlite3_wasm_extra_init.
+**
+** sqlite3_wasm_extra_init() must be a function with this signature:
+**
+**  int sqlite3_wasm_extra_init(const char *)
+**
+** and the sqlite3 library will call it with an argument of NULL one
+** time during sqlite3_initialize(). If it returns non-0,
+** initialization of the library will fail.
+*/
+
+#include "sqlite3.h"
+#include <stdio.h>
+
+int sqlite3_wasm_extra_init(const char *z){
+  fprintf(stderr,"%s: %s()\n", __FILE__, __func__);
+  return 0;
+}
diff --git a/ext/wasm/fiddle.make b/ext/wasm/fiddle.make
index cbe6ab3518..86984c9664 100644
--- a/ext/wasm/fiddle.make
+++ b/ext/wasm/fiddle.make
@@ -52,7 +52,7 @@ $(EXPORTED_FUNCTIONS.fiddle): $(fiddle.EXPORTED_FUNCTIONS.in) $(MAKEFILE.fiddle)
 
 fiddle-module.js := $(dir.fiddle)/fiddle-module.js
 fiddle-module.wasm := $(subst .js,.wasm,$(fiddle-module.js))
-fiddle.cses := $(dir.top)/shell.c $(sqlite3-wasm.c)
+fiddle.cses := $(dir.top)/shell.c $(sqlite3-wasm.cs)
 
 fiddle.SOAP.js := $(dir.fiddle)/$(notdir $(SOAP.js))
 $(fiddle.SOAP.js): $(SOAP.js)
diff --git a/manifest b/manifest
index ddcdbff760..46f6e1da0c 100644
--- a/manifest
+++ b/manifest
@@ -1,5 +1,5 @@
-C When\sa\stable-valued\sfunction\sappears\sas\sthe\sright\stable\sof\sa\sRIGHT\sJOIN,\nthe\sargument\sconstraints\son\sthe\stable-valued\sfunction\sshould\sbe\sconsidered\npart\sof\sthe\sON\sclause\sof\sthe\sRIGHT\sJOIN.\s\sFix\sfor\sthe\sproblem\sreported\nby\s[forum:/forumpost/422e635f3beafbf6|forum\spost\s422e635f3beafbf6].\s\sTest\ncases\sin\sTH3.\s\sPossibly\srelated\sto\sthe\senhancement\sat\s[501609eddf2a46d5].
-D 2023-02-26T20:57:09.904
+C Extend\swasm\sbuild\sto\senable\sinclusion\sof\sclient-custom\sC\scode,\sinitialized\svia\sthe\sSQLITE_EXTRA_INIT\smechanism,\sper\sdiscussion\sin\s[forum:1e1c04f3ed1bc96b|forum\spost\s1e1c04f3ed1bc96b].
+D 2023-02-27T07:12:28.112
 F .fossil-settings/empty-dirs dbb81e8fc0401ac46a1491ab34a7f2c7c0452f2f06b54ebb845d024ca8283ef1
 F .fossil-settings/ignore-glob 35175cdfcf539b2318cb04a9901442804be81cd677d8b889fcc9149c21f239ea
 F LICENSE.md df5091916dbb40e6e9686186587125e1b2ff51f022cc334e886c19a0e9982724
@@ -467,7 +467,7 @@ F ext/userauth/sqlite3userauth.h 7f3ea8c4686db8e40b0a0e7a8e0b00fac13aa7a3
 F ext/userauth/user-auth.txt e6641021a9210364665fe625d067617d03f27b04
 F ext/userauth/userauth.c 7f00cded7dcaa5d47f54539b290a43d2e59f4b1eb5f447545fa865f002fc80cb
 F ext/wasm/EXPORTED_FUNCTIONS.fiddle.in 27450c8b8c70875a260aca55435ec927068b34cef801a96205adb81bdcefc65c
-F ext/wasm/GNUmakefile 5a8dc82f5384a3deaaee777ed7eefd3c8cbcd0efe797a66925537d2b975af305
+F ext/wasm/GNUmakefile 122607cd0255134ae88bfdf6424f299d955b74bc8a6c48160c54c4ecbc7797b3
 F ext/wasm/README-dist.txt 6382cb9548076fca472fb3330bbdba3a55c1ea0b180ff9253f084f07ff383576
 F ext/wasm/README.md ef39861aa21632fdbca0bdd469f78f0096f6449a720f3f39642594af503030e9
 F ext/wasm/api/EXPORTED_FUNCTIONS.sqlite3-api d6a5078f48a5301ed17b9a30331075d9b2506e1360c1f0dee0c7816c10acd9ab
@@ -488,7 +488,7 @@ F ext/wasm/api/sqlite3-opfs-async-proxy.js 7795b84b66a7a8dedc791340709b310bb497c
 F ext/wasm/api/sqlite3-v-helper.js 6f6c3e390a72e08b0a5b16a0d567d7af3c04d172831853a29d72a6f1dd40ff24
 F ext/wasm/api/sqlite3-vfs-opfs.c-pp.js 0dfddd0fcd354817c3d5887decebb8a293cbb926c2639ba09b995a524f1085fb
 F ext/wasm/api/sqlite3-wasi.h 25356084cfe0d40458a902afb465df8c21fc4152c1d0a59b563a3fba59a068f9
-F ext/wasm/api/sqlite3-wasm.c 76625a70937a8522d014ef686c32db5b53a3ee61850323f5c601d2ac39fe52fe
+F ext/wasm/api/sqlite3-wasm.c 223d30c41d811cae8b9f1175fa68f2f1fb3cc056d16ad0def3b0ea5c65757a6c
 F ext/wasm/api/sqlite3-worker1-promiser.c-pp.js c5ac33e39f21a3481812d7333ca6e18853640d423a01960ca8dbc6e7c5c3c21c
 F ext/wasm/api/sqlite3-worker1.c-pp.js 77b3835192469e9da23926ec8f78fb0b114a51d048dc54388709ac22b5c5f0a0
 F ext/wasm/batch-runner.html 4deeed44fe41496dc6898d9fb17938ea3291f40f4bfb977e29d0cef96fbbe4c8
@@ -508,7 +508,8 @@ F ext/wasm/demo-worker1-promiser.js b99c550763fa792c204e9a7cceadd976004036d9fc3e
 F ext/wasm/demo-worker1.html 2c178c1890a2beb5a5fecb1453e796d067a4b8d3d2a04d65ca2eb1ab2c68ef5d
 F ext/wasm/demo-worker1.js a619adffc98b75b66c633b00f747b856449a134a9a0357909287d80a182d70fa
 F ext/wasm/dist.make f55f9c9e1980ea11a59964e59535c66175a17f004d1c2e274522c3366b3a084a
-F ext/wasm/fiddle.make dbe36b90b8907ae28ecb9c0e9fd8389dbdaecf117ea4fb2ea33864bdfa498a94
+F ext/wasm/example_extra_init.c 32c6ce5211409400ee875634d0071a3e4060b6b1d12417624a7e60a7c9d83c40
+F ext/wasm/fiddle.make 71b686d1f3355c0ce65cd76fb231e209dc30fbd2a3b0fd635bf26df904bffce4
 F ext/wasm/fiddle/emscripten.css 3d253a6fdb8983a2ac983855bfbdd4b6fa1ff267c28d69513dd6ef1f289ada3f
 F ext/wasm/fiddle/fiddle-worker.js 163d6139a93fab4bcb72064923df050d4e7c0ff0d8aa061ce8776a6e75da8a10
 F ext/wasm/fiddle/fiddle.js 974b995119ac443685d7d94d3b3c58c6a36540e9eb3fed7069d5653284071715
@@ -2046,8 +2047,8 @@ F vsixtest/vsixtest.tcl 6a9a6ab600c25a91a7acc6293828957a386a8a93
 F vsixtest/vsixtest.vcxproj.data 2ed517e100c66dc455b492e1a33350c1b20fbcdc
 F vsixtest/vsixtest.vcxproj.filters 37e51ffedcdb064aad6ff33b6148725226cd608e
 F vsixtest/vsixtest_TemporaryKey.pfx e5b1b036facdb453873e7084e1cae9102ccc67a0
-P 21aec65e5e2a01e58dd0bb8c8b9b29b8414373b53353fc7ca80a152fdd27566b
-R dd644aa05c12deae01f2f05d2c4bf4e4
-U drh
-Z 73efc57a25cea16beea22ea8fc7c8752
+P 46639f682975dac6efec4e230aca2c9b127b4fc77e0b465fad38ef4caa9b7a4c
+R 2852837dfc2447b63257f54764575344
+U stephan
+Z 644646fdf69d91f54f8f3e9a045a3c06
 # Remove this line to create a well-formed Fossil manifest.
diff --git a/manifest.uuid b/manifest.uuid
index f5d539d572..9c8f628bd6 100644
--- a/manifest.uuid
+++ b/manifest.uuid
@@ -1 +1 @@
-46639f682975dac6efec4e230aca2c9b127b4fc77e0b465fad38ef4caa9b7a4c
\ No newline at end of file
+68a52cafff60f19c9c998133d04f192b1e8b23f78b8cee13807d76845ef5e13d
\ No newline at end of file