Handle 64-bit arguments with Emscripten legalization.

Author: shoestringr

dist/wa-sqlite-async.mjs

@@ -7,9 +7,9 @@
 // sqlite3_io_methods javascript handlers
 // 64-bit integer parameters are passed by pointer.
 extern int vfsClose(sqlite3_file* file);
-extern int vfsRead(sqlite3_file* file, void* pData, int iAmt, const sqlite3_int64* iOffset);
-extern int vfsWrite(sqlite3_file* file, const void* pData, int iAmt, const sqlite3_int64* iOffset);
-extern int vfsTruncate(sqlite3_file* file, const sqlite3_int64* size);
+extern int vfsRead(sqlite3_file* file, void* pData, int iAmt, sqlite3_int64 iOffset);
+extern int vfsWrite(sqlite3_file* file, const void* pData, int iAmt, sqlite3_int64 iOffset);
+extern int vfsTruncate(sqlite3_file* file, sqlite3_int64 size);
 extern int vfsSync(sqlite3_file* file, int flags);
 extern int vfsFileSize(sqlite3_file* file, sqlite3_int64* pSize);
 extern int vfsLock(sqlite3_file* file, int flags);
@@ -23,24 +23,13 @@ extern int vfsOpen(sqlite3_vfs* vfs, const char *zName, sqlite3_file* file, int
 extern int vfsDelete(sqlite3_vfs* vfs, const char *zName, int syncDir);
 extern int vfsAccess(sqlite3_vfs* vfs, const char *zName, int flags, int *pResOut);
 
-// Glue functions to pass 64-bit integers by pointer.
-static int xRead(sqlite3_file* file, void* pData, int iAmt, sqlite3_int64 iOffset) {
-  return vfsRead(file, pData, iAmt, &iOffset);
-}
-static int xWrite(sqlite3_file* file, const void* pData, int iAmt, sqlite3_int64 iOffset) {
-  return vfsWrite(file, pData, iAmt, &iOffset);
-}
-static int xTruncate(sqlite3_file* file, sqlite3_int64 size) {
-  return vfsTruncate(file, &size);
-}
-
 static int xOpen(sqlite3_vfs* vfs, const char* zName, sqlite3_file* file, int flags, int* pOutFlags) {
   static sqlite3_io_methods io_methods = {
     1,
     vfsClose,
-    xRead,
-    xWrite,
-    xTruncate,
+    vfsRead,
+    vfsWrite,
+    vfsTruncate,
     vfsSync,
     vfsFileSize,
     vfsLock,

dist/wa-sqlite-async.wasm

@@ -65,11 +65,10 @@ const vfs_methods = {
       });
     }
 
-    // Convert 64-bit unsigned int in WASM memory to Number. The unsigned
-    // int is assumed to be <= Number.MAX_SAFE_INTEGER;
-    function u64(ptr) {
-      const index = ptr >> 2;
-      return HEAPU32[index] + (HEAPU32[index + 1] * (2**32));
+    // Emscripten "legalizes" 64-bit integer arguments by passing them as
+    // two 32-bit signed integers.
+    function delegalize(lo32, hi32) {
+      return (hi32 * 0x100000000) + lo32 + (lo32 < 0 ? 2**32 : 0);
     }
 
     const closedFiles = hasAsyncify ? new Set() : null;
@@ -92,23 +91,23 @@ const vfs_methods = {
     }
 
     // int xRead(sqlite3_file* file, void* pData, int iAmt, sqlite3_int64 iOffset);
-    _vfsRead = function(file, pData, iAmt, iOffset) {
+    _vfsRead = function(file, pData, iAmt, iOffsetLo, iOffsetHi) {
       const vfs = mapFileToVFS.get(file);
       const pDataArray = HEAPU8.subarray(pData, pData + iAmt);
-      return vfs['xRead'](file, pDataArray, u64(iOffset));
+      return vfs['xRead'](file, pDataArray, delegalize(iOffsetLo, iOffsetHi));
     }
 
     // int xWrite(sqlite3_file* file, const void* pData, int iAmt, sqlite3_int64 iOffset);
-    _vfsWrite = function(file, pData, iAmt, iOffset) {
+    _vfsWrite = function(file, pData, iAmt, iOffsetLo, iOffsetHi) {
       const vfs = mapFileToVFS.get(file);
       const pDataArray = HEAPU8.subarray(pData, pData + iAmt);
-      return vfs['xWrite'](file, pDataArray, u64(iOffset));
+      return vfs['xWrite'](file, pDataArray, delegalize(iOffsetLo, iOffsetHi));
     }
 
     // int xTruncate(sqlite3_file* file, sqlite3_int64 size);
-    _vfsTruncate = function(file, iSize) {
+    _vfsTruncate = function(file, iSizeLo, iSizeHi) {
       const vfs = mapFileToVFS.get(file);
-      return vfs['xTruncate'](file, u64(iSize));
+      return vfs['xTruncate'](file, delegalize(iSizeLo, iSizeHi));
     }
 
     // int xSync(sqlite3_file* file, int flags);