Towards VFS API.

conn.go

@@ -278,7 +278,7 @@ func (c *Conn) SetInterrupt(ctx context.Context) (old context.Context) {
 			break
 
 		case <-ctx.Done(): // Done was closed.
-			buf := util.View(c.mod, c.handle+c.api.interrupt, 4)
+			buf := util.View(c.mod, c.handle+280, 4)
 			(*atomic.Uint32)(unsafe.Pointer(&buf[0])).Store(1)
 			// Wait for the next call to SetInterrupt.
 			<-waiter
@@ -294,7 +294,7 @@ func (c *Conn) checkInterrupt() bool {
 	if c.interrupt == nil || c.interrupt.Err() == nil {
 		return false
 	}
-	buf := util.View(c.mod, c.handle+c.api.interrupt, 4)
+	buf := util.View(c.mod, c.handle+280, 4)
 	(*atomic.Uint32)(unsafe.Pointer(&buf[0])).Store(1)
 	return true
 }

embed/exports.txt

@@ -44,5 +44,4 @@ sqlite3_backup_init
 sqlite3_backup_step
 sqlite3_backup_finish
 sqlite3_backup_remaining
-sqlite3_backup_pagecount
-sqlite3_interrupt_offset
+sqlite3_backup_pagecount

internal/vfs/tests/mptest/testdata/main.c

@@ -8,18 +8,11 @@
 // VFS
 #include "vfs.c"
 
-sqlite3_destructor_type malloc_destructor = &free;
-size_t sqlite3_interrupt_offset = offsetof(sqlite3, u1.isInterrupted);
-
-int sqlite3_os_init() {
-  return sqlite3_vfs_register(os_vfs(), /*default=*/true);
-}
-
-__attribute__((constructor)) void premain() { sqlite3_initialize(); }
+__attribute__((constructor)) void init() { sqlite3_initialize(); }
 
 static int dont_unlink(const char *pathname) { return 0; }
 #define sqlite3_enable_load_extension(...)
 #define sqlite3_trace(...)
 #define unlink dont_unlink
 #undef UNUSED_PARAMETER
-#include "mptest.c"
+#include "mptest.c"

internal/vfs/tests/mptest/testdata/mptest.wasm

@@ -1,3 +1,3 @@
 version https://git-lfs.github.com/spec/v1
-oid sha256:37ceeed293b9f09e9770b40eda3f625447f5a3a74208709886d4411d12f93414
-size 1486113
+oid sha256:aafb873c26d32dbf7498e4c4dd243eb6411c056432818121463d8cb49bc15f70
+size 1479293

internal/vfs/tests/speedtest1/testdata/main.c

@@ -8,12 +8,5 @@
 // VFS
 #include "vfs.c"
 
-sqlite3_destructor_type malloc_destructor = &free;
-size_t sqlite3_interrupt_offset = offsetof(sqlite3, u1.isInterrupted);
-
-int sqlite3_os_init() {
-  return sqlite3_vfs_register(os_vfs(), /*default=*/true);
-}
-
 #define randomFunc(args...) randomFunc2(args)
-#include "speedtest1.c"
+#include "speedtest1.c"

internal/vfs/tests/speedtest1/testdata/speedtest1.wasm

@@ -1,3 +1,3 @@
 version https://git-lfs.github.com/spec/v1
-oid sha256:8167119c344a68217b0301e2e8c288f2e75611d296d7822f841b65911da0275c
-size 1520569
+oid sha256:2638f5458f93b60f97006456f60e3e294cffb9ac22b20dba748fbd12e34f056d
+size 1515841

internal/vfs/vfs.go

@@ -18,6 +18,7 @@ import (
 )
 
 func Export(env wazero.HostModuleBuilder) wazero.HostModuleBuilder {
+	util.RegisterFuncII(env, "go_vfs_find", vfsFind)
 	util.RegisterFuncIIJ(env, "go_localtime", vfsLocaltime)
 	util.RegisterFuncIIII(env, "go_randomness", vfsRandomness)
 	util.RegisterFuncIII(env, "go_sleep", vfsSleep)
@@ -62,6 +63,10 @@ func (vfs *vfsState) Close() error {
 	return nil
 }
 
+func vfsFind(ctx context.Context, mod api.Module, zVfsName uint32) uint32 {
+	return 0
+}
+
 func vfsLocaltime(ctx context.Context, mod api.Module, pTm uint32, t int64) _ErrorCode {
 	tm := time.Unix(t, 0)
 	var isdst int

module.go

@@ -153,7 +153,6 @@ func newModule(mod api.Module) (m *module, err error) {
 		backupFinish:    getFun("sqlite3_backup_finish"),
 		backupRemaining: getFun("sqlite3_backup_remaining"),
 		backupPageCount: getFun("sqlite3_backup_pagecount"),
-		interrupt:       getVal("sqlite3_interrupt_offset"),
 	}
 	if err != nil {
 		return nil, err
@@ -356,5 +355,4 @@ type sqliteAPI struct {
 	backupRemaining api.Function
 	backupPageCount api.Function
 	destructor      uint32
-	interrupt       uint32
 }

sqlite3/main.c

@@ -16,13 +16,6 @@
 #include "ext/uuid.c"
 #include "time.c"
 
-sqlite3_destructor_type malloc_destructor = &free;
-size_t sqlite3_interrupt_offset = offsetof(sqlite3, u1.isInterrupted);
-
-int sqlite3_os_init() {
-  return sqlite3_vfs_register(os_vfs(), /*default=*/true);
-}
-
 __attribute__((constructor)) void init() {
   sqlite3_initialize();
   sqlite3_auto_extension((void (*)(void))sqlite3_base_init);

sqlite3/sqlite_cfg.h

@@ -59,9 +59,12 @@
 #define SECOND(...) SECOND_I(__VA_ARGS__, , )
 #define SECOND_I(A, B, ...) B
 #define GLUE(A, B) GLUE_I(A, B)
-#define GLUE_I(A, B) A##B
-#define REPLACE_DEFAULT(a, prefix) SECOND(GLUE(prefix, __LINE__), a)
-#define REPLACE_AT_LINE(a) , a
+#define GLUE_I(A, B) A##_##B
+#define CREATE_REPLACER(A) SECOND(GLUE(A, __LINE__), A)
+#define REPLACE_AT_LINE(A) , A
 
 // Implemented in vfs.c.
-int localtime_s(struct tm *const pTm, time_t const *const pTime);
+int localtime_s(struct tm *const pTm, time_t const *const pTime);
+
+#define sqlite3_vfs_find CREATE_REPLACER(sqlite3_vfs_find_wrapper)
+#define sqlite3_vfs_find_wrapper_25397 REPLACE_AT_LINE(sqlite3_vfs_find)

sqlite3/vfs.c

@@ -3,6 +3,7 @@
 #include "sqlite3.h"
 
 int go_localtime(struct tm *, sqlite3_int64);
+int go_vfs_find(const char *zVfsName);
 
 int go_randomness(sqlite3_vfs *, int nByte, char *zOut);
 int go_sleep(sqlite3_vfs *, int microseconds);
@@ -60,9 +61,7 @@ struct go_file {
   int handle;
 };
 
-static_assert(offsetof(struct go_file, handle) == 4, "Unexpected offset");
-
-sqlite3_vfs *os_vfs() {
+int sqlite3_os_init() {
   static sqlite3_vfs os_vfs = {
       .iVersion = 2,
       .szOsFile = sizeof(struct go_file),
@@ -79,9 +78,61 @@ sqlite3_vfs *os_vfs() {
       .xCurrentTime = go_current_time,
       .xCurrentTimeInt64 = go_current_time_64,
   };
-  return &os_vfs;
+  return sqlite3_vfs_register(&os_vfs, /*default=*/true);
 }
 
+sqlite3_destructor_type malloc_destructor = &free;
+
 int localtime_s(struct tm *const pTm, time_t const *const pTime) {
   return go_localtime(pTm, (sqlite3_int64)*pTime);
 }
+
+#undef sqlite3_vfs_find
+sqlite3_vfs *sqlite3_vfs_find_wrapper(const char *zVfsName) {
+  if (zVfsName) {
+    static sqlite3_vfs *go_vfs_list;
+    sqlite3_vfs *found = NULL;
+    for (sqlite3_vfs **next = &go_vfs_list; *next;) {
+      sqlite3_vfs *it = *next;
+      if (go_vfs_find(it->zName)) {
+        if (!strcmp(zVfsName, it->zName)) found = it;
+        next = &it->pNext;
+      } else {
+        *next = it->pNext;
+        free(it);
+      }
+    }
+    if (found) {
+      return found;
+    }
+    if (go_vfs_find(zVfsName)) {
+      sqlite3_vfs *prev = go_vfs_list;
+      go_vfs_list = malloc(sizeof(sqlite3_vfs) + strlen(zVfsName) + 1);
+      char *name = (char *)(go_vfs_list + 1);
+      strcpy(name, zVfsName);
+      *go_vfs_list = (sqlite3_vfs){
+          .iVersion = 2,
+          .szOsFile = sizeof(struct go_file),
+          .mxPathname = 512,
+          .zName = name,
+          .pNext = prev,
+
+          .xOpen = go_open_wrapper,
+          .xDelete = go_delete,
+          .xAccess = go_access,
+          .xFullPathname = go_full_pathname,
+
+          .xRandomness = go_randomness,
+          .xSleep = go_sleep,
+          .xCurrentTime = go_current_time,
+          .xCurrentTimeInt64 = go_current_time_64,
+      };
+      return go_vfs_list;
+    }
+  }
+  return sqlite3_vfs_find(zVfsName);
+}
+
+static_assert(offsetof(struct go_file, handle) == 4, "Unexpected offset");
+static_assert(offsetof(sqlite3_vfs, zName) == 16, "Unexpected offset");
+static_assert(offsetof(sqlite3, u1.isInterrupted) == 280, "Unexpected offset");