Merge kv-vfs branch into fiddle-opfs branch to add kvvfs-based wasm build and demo.

FossilOrigin-Name: a7d8b26acd3c1ae344369e4d70804c0cab45272c0983cfd32d616a0a7b28acb9

Makefile.in

@@ -184,7 +184,7 @@ LIBOBJS0 = alter.lo analyze.lo attach.lo auth.lo \
          main.lo malloc.lo mem0.lo mem1.lo mem2.lo mem3.lo mem5.lo \
          memdb.lo memjournal.lo \
          mutex.lo mutex_noop.lo mutex_unix.lo mutex_w32.lo \
-         notify.lo opcodes.lo os.lo os_unix.lo os_win.lo \
+         notify.lo opcodes.lo os.lo os_kv.lo os_unix.lo os_win.lo \
          pager.lo parse.lo pcache.lo pcache1.lo pragma.lo prepare.lo printf.lo \
          random.lo resolve.lo rowset.lo rtree.lo \
          sqlite3session.lo select.lo sqlite3rbu.lo status.lo stmt.lo \
@@ -257,6 +257,7 @@ SRC = \
   $(TOP)/src/os.h \
   $(TOP)/src/os_common.h \
   $(TOP)/src/os_setup.h \
+  $(TOP)/src/os_kv.c \
   $(TOP)/src/os_unix.c \
   $(TOP)/src/os_win.c \
   $(TOP)/src/os_win.h \
@@ -492,6 +493,7 @@ TESTSRC2 = \
   $(TOP)/src/main.c \
   $(TOP)/src/mem5.c \
   $(TOP)/src/os.c \
+  $(TOP)/src/os_kv.c \
   $(TOP)/src/os_unix.c \
   $(TOP)/src/os_win.c \
   $(TOP)/src/pager.c \
@@ -938,6 +940,9 @@ pcache1.lo:	$(TOP)/src/pcache1.c $(HDR) $(TOP)/src/pcache.h
 os.lo:	$(TOP)/src/os.c $(HDR)
 	$(LTCOMPILE) $(TEMP_STORE) -c $(TOP)/src/os.c
 
+os_kv.lo:	$(TOP)/src/os_kv.c $(HDR)
+	$(LTCOMPILE) $(TEMP_STORE) -c $(TOP)/src/os_kv.c
+
 os_unix.lo:	$(TOP)/src/os_unix.c $(HDR)
 	$(LTCOMPILE) $(TEMP_STORE) -c $(TOP)/src/os_unix.c
 

ext/wasm/GNUmakefile

@@ -380,6 +380,8 @@ speedtest1: $(speedtest1.js)
 all: $(speedtest1.js)
 CLEAN_FILES += $(speedtest1.js) $(speedtest1.wasm)
 # end speedtest1.js
+########################################################################
+
 ########################################################################
 # fiddle_remote is the remote destination for the fiddle app. It
 # must be a [user@]HOST:/path for rsync.
@@ -402,3 +404,5 @@ push-fiddle: $(fiddle_files)
 	rsync -va fiddle/ $(fiddle_remote)
 # end fiddle remote push
 ########################################################################
+
+include kvvfs.make

ext/wasm/api/sqlite3-api-cleanup.js

@@ -39,7 +39,7 @@ if('undefined' !== typeof Module){ // presumably an Emscripten build
   delete self.sqlite3ApiBootstrap;
 
   if(self.location && +self.location.port > 1024){
-    console.warn("Installing sqlite3 bits as global S for dev-testing purposes.");
+    console.warn("Installing sqlite3 bits as global S for local dev/test purposes.");
     self.S = sqlite3;
   }
 

ext/wasm/api/sqlite3-api-oo1.js

@@ -70,6 +70,74 @@ self.sqlite3ApiBootstrap.initializers.push(function(sqlite3){
   const toss3 = (...args)=>{throw new SQLite3Error(...args)};
   sqlite3.SQLite3Error = SQLite3Error;
 
+  // Documented in DB.checkRc()
+  const checkSqlite3Rc = function(dbPtr, sqliteResultCode){
+    if(sqliteResultCode){
+      if(dbPtr instanceof DB) dbPtr = dbPtr.pointer;
+      throw new SQLite3Error(
+        "sqlite result code",sqliteResultCode+":",
+        (dbPtr
+         ? capi.sqlite3_errmsg(dbPtr)
+         : capi.sqlite3_errstr(sqliteResultCode))
+      );
+    }
+  };
+
+  /**
+     A proxy for DB class constructors. It must be called with the
+     being-construct DB object as its "this".
+  */
+  const dbCtorHelper = function ctor(fn=':memory:', flags='c', vfsName){
+    if(!ctor._name2vfs){
+      // Map special filenames which we handle here (instead of in C)
+      // to some helpful metadata...
+      ctor._name2vfs = Object.create(null);
+      const isWorkerThread = (self.window===self /*===running in main window*/)
+          ? false
+          : (n)=>toss3("The VFS for",n,"is only available in the main window thread.")
+      ctor._name2vfs[':localStorage:'] = {
+        vfs: 'kvvfs',
+        filename: isWorkerThread || (()=>'local')
+      };
+      ctor._name2vfs[':sessionStorage:'] = {
+        vfs: 'kvvfs',
+        filename: isWorkerThread || (()=>'session')
+      };
+    }
+    if('string'!==typeof fn){
+      toss3("Invalid filename for DB constructor.");
+    }
+    const vfsCheck = ctor._name2vfs[fn];
+    if(vfsCheck){
+      vfsName = vfsCheck.vfs;
+      fn = vfsCheck.filename(fn);
+    }
+    let ptr, oflags = 0;
+    if( flags.indexOf('c')>=0 ){
+      oflags |= capi.SQLITE_OPEN_CREATE | capi.SQLITE_OPEN_READWRITE;
+    }
+    if( flags.indexOf('w')>=0 ) oflags |= capi.SQLITE_OPEN_READWRITE;
+    if( 0===oflags ) oflags |= capi.SQLITE_OPEN_READONLY;
+    oflags |= capi.SQLITE_OPEN_EXRESCODE;
+    const stack = capi.wasm.scopedAllocPush();
+    try {
+      const ppDb = capi.wasm.scopedAllocPtr() /* output (sqlite3**) arg */;
+      const pVfsName = vfsName ? capi.wasm.scopedAllocCString(vfsName) : 0;
+      const rc = capi.sqlite3_open_v2(fn, ppDb, oflags, pVfsName);
+      ptr = capi.wasm.getPtrValue(ppDb);
+      checkSqlite3Rc(ptr, rc);
+    }catch( e ){
+      if( ptr ) capi.sqlite3_close_v2(ptr);
+      throw e;
+    }finally{
+      capi.wasm.scopedAllocPop(stack);
+    }
+    this.filename = fn;
+    __ptrMap.set(this, ptr);
+    __stmtMap.set(this, Object.create(null));
+    __udfMap.set(this, Object.create(null));
+  };
+  
   /**
      The DB class provides a high-level OO wrapper around an sqlite3
      db handle.
@@ -102,42 +170,29 @@ self.sqlite3ApiBootstrap.initializers.push(function(sqlite3){
      "c". These modes are ignored for the special ":memory:" and ""
      names.
 
-     The final argument is currently unimplemented but will eventually
+     The final argument is analogous to the final argument of
-     be used to specify an optional sqlite3 VFS implementation name,
+     sqlite3_open_v2(): the name of an sqlite3 VFS. Pass a falsy value,
-     as for the final argument to sqlite3_open_v2().
+     or not at all, to use the default. If passed a value, it must
+     be the string name of a VFS
 
      For purposes of passing a DB instance to C-style sqlite3
      functions, the DB object's read-only `pointer` property holds its
      `sqlite3*` pointer value. That property can also be used to check
      whether this DB instance is still open.
+
+
+     EXPERIMENTAL: in the main window thread, the filenames
+     ":localStorage:" and ":sessionStorage:" are special: they cause
+     the db to use either localStorage or sessionStorage for storing
+     the database. In this mode, only a single database is permitted
+     in each storage object. This feature is experimental and subject
+     to any number of changes (including outright removal). This
+     support requires a specific build of sqlite3, the existence of
+     which can be determined at runtime by checking for a non-0 return
+     value from sqlite3.capi.sqlite3_vfs_find("kvvfs").
   */
-  const DB = function ctor(fn=':memory:', flags='c', vtab="not yet implemented"){
+  const DB = function ctor(fn=':memory:', flags='c', vfsName){
-    if('string'!==typeof fn){
+    dbCtorHelper.apply(this, Array.prototype.slice.call(arguments));
-      toss3("Invalid filename for DB constructor.");
-    }
-    let ptr, oflags = 0;
-    if( flags.indexOf('c')>=0 ){
-      oflags |= capi.SQLITE_OPEN_CREATE | capi.SQLITE_OPEN_READWRITE;
-    }
-    if( flags.indexOf('w')>=0 ) oflags |= capi.SQLITE_OPEN_READWRITE;
-    if( 0===oflags ) oflags |= capi.SQLITE_OPEN_READONLY;
-    oflags |= capi.SQLITE_OPEN_EXRESCODE;
-    const stack = capi.wasm.scopedAllocPush();
-    try {
-      const ppDb = capi.wasm.scopedAllocPtr() /* output (sqlite3**) arg */;
-      const rc = capi.sqlite3_open_v2(fn, ppDb, oflags, null);
-      ptr = capi.wasm.getPtrValue(ppDb);
-      ctor.checkRc(ptr, rc);
-    }catch( e ){
-      if( ptr ) capi.sqlite3_close_v2(ptr);
-      throw e;
-    }finally{
-      capi.wasm.scopedAllocPop(stack);
-    }
-    this.filename = fn;
-    __ptrMap.set(this, ptr);
-    __stmtMap.set(this, Object.create(null));
-    __udfMap.set(this, Object.create(null));
   };
 
   /**
@@ -232,6 +287,8 @@ self.sqlite3ApiBootstrap.initializers.push(function(sqlite3){
           }else if(args[0] && 'object'===typeof args[0]){
             out.opt = args[0];
             out.sql = out.opt.sql;
+          }else if(Array.isArray(args[0])){
+            out.sql = args[0];
           }
           break;
         case 2:
@@ -295,17 +352,7 @@ self.sqlite3ApiBootstrap.initializers.push(function(sqlite3){
      non-0 non-error codes need to be checked for in
      client code where they are expected.
   */
-  DB.checkRc = function(dbPtr, sqliteResultCode){
+  DB.checkRc = checkSqlite3Rc;
-    if(sqliteResultCode){
-      if(dbPtr instanceof DB) dbPtr = dbPtr.pointer;
-      throw new SQLite3Error(
-        "sqlite result code",sqliteResultCode+":",
-        (dbPtr
-         ? capi.sqlite3_errmsg(dbPtr)
-         : capi.sqlite3_errstr(sqliteResultCode))
-      );
-    }
-  };
 
   DB.prototype = {
     /**
@@ -1532,5 +1579,19 @@ self.sqlite3ApiBootstrap.initializers.push(function(sqlite3){
     DB,
     Stmt
   }/*oo1 object*/;
+
+  if( self.window===self && 0!==capi.sqlite3_vfs_find('kvvfs') ){
+    /* In the main window thread, add a couple of convenience proxies
+       for localStorage and sessionStorage DBs... */
+    let klass = sqlite3.oo1.LocalStorageDb = function(){
+      dbCtorHelper.call(this, 'local', 'c', 'kvvfs');
+    };
+    klass.prototype = DB.prototype;
+
+    klass = sqlite3.oo1.SessionStorageDb = function(){
+      dbCtorHelper.call(this, 'session', 'c', 'kvvfs');
+    };
+    klass.prototype = DB.prototype;
+  }
 });
 

ext/wasm/api/sqlite3-api-prologue.js

@@ -713,7 +713,7 @@ self.sqlite3ApiBootstrap = function sqlite3ApiBootstrap(
       return __persistentDir = "";
     }
     try{
-      if(pdir && 0===this.wasm.xCallWrapped(
+      if(pdir && 0===capi.wasm.xCallWrapped(
         'sqlite3_wasm_init_opfs', 'i32', ['string'], pdir
       )){
         /** OPFS does not support locking and will trigger errors if
@@ -736,7 +736,7 @@ self.sqlite3ApiBootstrap = function sqlite3ApiBootstrap(
       // sqlite3_wasm_init_opfs() is not available
       return __persistentDir = "";
     }
-  }.bind(capi);
+  };
 
   /**
      Returns true if sqlite3.capi.sqlite3_web_persistent_dir() is a
@@ -744,9 +744,15 @@ self.sqlite3ApiBootstrap = function sqlite3ApiBootstrap(
      prefix, else returns false.
   */
   capi.sqlite3_web_filename_is_persistent = function(name){
-    const p = this.sqlite3_web_persistent_dir();
+    const p = capi.sqlite3_web_persistent_dir();
     return (p && name) ? name.startsWith(p) : false;
-  }.bind(capi);
+  };
+  
+  if(0===capi.wasm.exports.sqlite3_vfs_find(0)){
+    /* Assume that sqlite3_initialize() has not yet been called.
+       This will be the case in an SQLITE_OS_KV build. */
+    capi.wasm.exports.sqlite3_initialize();
+  }
 
   /* The remainder of the API will be set up in later steps. */
   const sqlite3 = {

ext/wasm/api/sqlite3-wasm.c

@@ -523,226 +523,5 @@ int sqlite3_wasm_init_opfs(void){
 }
 #endif /* __EMSCRIPTEN__ && SQLITE_WASM_OPFS */
 
-#if defined(__EMSCRIPTEN__) // && defined(SQLITE_OS_KV)
-#include <emscripten.h>
-#include <emscripten/console.h>
-
-#ifndef KVSTORAGE_KEY_SZ
-/* We can remove this once kvvfs and this bit is merged. */
-#  define KVSTORAGE_KEY_SZ 32
-static void kvstorageMakeKey(
-  const char *zClass,
-  const char *zKeyIn,
-  char *zKeyOut
-){
-  sqlite3_snprintf(KVSTORAGE_KEY_SZ, zKeyOut, "kvvfs-%s-%s", zClass, zKeyIn);
-}
-#endif
-
-/*
-** An internal level of indirection for accessing the static
-** kvstorageMakeKey() from EM_JS()-generated functions. This must be
-** made available for export via Emscripten but is not intended to be
-** used from client code. If called with a NULL zKeyOut it is a no-op.
-** It returns KVSTORAGE_KEY_SZ, so JS code (which cannot see that
-** constant) may call it with NULL arguments to get the size of the
-** allocation they'll need for a kvvfs key.
-**
-** Maintenance reminder: Emscripten will install this in the Module
-** init scope and will prefix its name with "_".
-*/
-WASM_KEEP
-int sqlite3_wasm__kvvfsMakeKey(const char *zClass,
-                                  const char *zKeyIn,
-                                  char *zKeyOut){
-  if(zKeyOut) kvstorageMakeKey(zClass, zKeyIn, zKeyOut);
-  return KVSTORAGE_KEY_SZ;
-}
-
-#if 0
-/*
-** Alternately, we can implement kvstorageMakeKey() in JS in such a
-** way that it's visible to kvstorageWrite/Delete/Read() but not the
-** rest of the world. This impl is considerably more verbose than the
-** C impl because writing directly to memory requires more code in
-** JS. Though more verbose, this approach enables removal of
-** sqlite3_wasm__kvvfsMakeKey(). The only catch is that the
-** KVSTORAGE_KEY_SZ constant has to be hard-coded into this function.
-*/
-EM_JS(void, kvstorageMakeKeyJS,
-      (const char *zClass, const char *zKeyIn, char *zKeyOut),{
-  const max = 32;
-  if(!arguments.length) return max;
-  let n = 0, i = 0, ch = 0;
-  // Write key prefix to dest...
-  if(0){
-    const prefix = "kvvfs-";
-    for(i in prefix) setValue(zKeyOut+(n++), prefix.charCodeAt(i));
-  }else{
-    // slightly optimized but less readable...
-    setValue(zKeyOut + (n++), 107/*'k'*/);
-    setValue(zKeyOut + (n++), 118/*'v'*/);
-    setValue(zKeyOut + (n++), 118/*'v'*/);
-    setValue(zKeyOut + (n++), 102/*'f'*/);
-    setValue(zKeyOut + (n++), 115/*'s'*/);
-    setValue(zKeyOut + (n++),  45/*'-'*/);
-  }
-  // Write zClass to dest...
-  for(i = 0; n < max && (ch = getValue(zClass+i)); ++n, ++i){
-    setValue(zKeyOut + n, ch);
-  }
-  // Write "-" separator to dest...
-  if(n<max) setValue(zKeyOut + (n++), 45/* == '-'*/);
-  // Write zKeyIn to dest...
-  for(i = 0; n < max && (ch = getValue(zKeyIn+i)); ++n, ++i){
-    setValue(zKeyOut + n, ch);
-  }
-  // NUL terminate...
-  if(n<max) setValue(zKeyOut + n, 0);
-});
-#endif
-
-/*
-** Internal helper for kvstorageWrite/Read/Delete() which creates a
-** storage key for the given zClass/zKeyIn combination. Returns a
-** pointer to the key: a C string allocated on the WASM stack, or 0 if
-** allocation fails. It is up to the caller to save/restore the stack
-** before/after this operation.
-*/
-EM_JS(const char *, kvstorageMakeKeyOnJSStack,
-      (const char *zClass, const char *zKeyIn),{
-  if( 0==zClass || 0==zKeyIn) return 0;
-  const zXKey = stackAlloc(_sqlite3_wasm__kvvfsMakeKey(0,0,0));
-  if(zXKey) _sqlite3_wasm__kvvfsMakeKey(zClass, zKeyIn, zXKey);
-  return zXKey;
-});
-
-/*
-** JS impl of kvstorageWrite(). Main docs are in the C impl. This impl
-** writes zData to the global sessionStorage (if zClass starts with
-** 's') or localStorage, using a storage key derived from zClass and
-** zKey.
-*/
-EM_JS(int, kvstorageWrite,
-      (const char *zClass, const char *zKey, const char *zData),{
-  const stack = stackSave();
-  try {
-    const zXKey = kvstorageMakeKeyOnJSStack(zClass,zKey);
-    if(!zXKey) return 1/*OOM*/;
-    const jKey = UTF8ToString(zXKey);
-    /**
-       We could simplify this function and eliminate the
-       kvstorageMakeKey() symbol acrobatics if we'd simply hard-code
-       the key algo into the 3 functions which need it:
-
-       const jKey = "kvvfs-"+UTF8ToString(zClass)+"-"+UTF8ToString(zKey);
-    */
-    ((115/*=='s'*/===getValue(zClass))
-     ? sessionStorage : localStorage).setItem(jKey, UTF8ToString(zData));
-  }catch(e){
-    console.error("kvstorageWrite()",e);
-    return 1; // Can't access SQLITE_xxx from here
-  }finally{
-    stackRestore(stack);
-  }
-  return 0;
-});
-
-/*
-** JS impl of kvstorageDelete(). Main docs are in the C impl. This
-** impl generates a key derived from zClass and zKey, and removes the
-** matching entry (if any) from global sessionStorage (if zClass
-** starts with 's') or localStorage.
-*/
-EM_JS(int, kvstorageDelete,
-      (const char *zClass, const char *zKey),{
-  const stack = stackSave();
-  try {
-    const zXKey = kvstorageMakeKeyOnJSStack(zClass,zKey);
-    if(!zXKey) return 1/*OOM*/;
-    _sqlite3_wasm__kvvfsMakeKey(zClass, zKey, zXKey);
-    const jKey = UTF8ToString(zXKey);
-    ((115/*=='s'*/===getValue(zClass))
-     ? sessionStorage : localStorage).removeItem(jKey);
-  }catch(e){
-    console.error("kvstorageDelete()",e);
-    return 1;
-  }finally{
-    stackRestore(stack);
-  }
-  return 0;
-});
-
-/*
-** JS impl of kvstorageRead(). Main docs are in the C impl. This impl
-** reads its data from the global sessionStorage (if zClass starts
-** with 's') or localStorage, using a storage key derived from zClass
-** and zKey.
-*/
-EM_JS(int, kvstorageRead,
-      (const char *zClass, const char *zKey, char *zBuf, int nBuf),{
-  const stack = stackSave();
-  try {
-    const zXKey = kvstorageMakeKeyOnJSStack(zClass,zKey);
-    if(!zXKey) return -3/*OOM*/;
-    const jKey = UTF8ToString(zXKey);
-    const jV = ((115/*=='s'*/===getValue(zClass))
-                ? sessionStorage : localStorage).getItem(jKey);
-    if(!jV) return -1;
-    const nV = jV.length /* Note that we are relying 100% on v being
-                            ASCII so that jV.length is equal to the
-                            C-string's byte length. */;
-    if(nBuf<=0) return nV;
-    else if(1===nBuf){
-      setValue(zBuf, 0);
-      return nV;
-    }
-    const zV = allocateUTF8OnStack(jV);
-    if(nBuf > nV + 1) nBuf = nV + 1;
-    HEAPU8.copyWithin(zBuf, zV, zV + nBuf - 1);
-    setValue( zBuf + nBuf - 1, 0 );
-    return nBuf - 1;
-  }catch(e){
-    console.error("kvstorageRead()",e);
-    return -2;
-  }finally{
-    stackRestore(stack);
-  }
-});
-
-/*
-** This function exists for (1) WASM testing purposes and (2) as a
-** hook to get Emscripten to export several EM_JS()-generated
-** functions. It is not part of the public API and its signature
-** and semantics may change at any time.
-*/
-WASM_KEEP
-int sqlite3_wasm__emjs_keep(int whichOp){
-  int rc = 0;
-  const char * zClass = "session";
-  const char * zKey = "hello";
-  switch( whichOp ){
-    case 0: break;
-    case 1:
-      kvstorageWrite(zClass, zKey, "world");
-      break;
-    case 2: {
-      char buffer[128] = {0};
-      char * zBuf = &buffer[0];
-      rc = kvstorageRead(zClass, zKey, zBuf, (int)sizeof(buffer));
-      emscripten_console_logf("kvstorageRead()=%d %s\n", rc, zBuf);
-      break;
-    }
-    case 3:
-      kvstorageDelete(zClass, zKey);
-      break;
-    case 4:
-      kvstorageMakeKeyOnJSStack(0,0) /* force Emscripten to include this */;
-      break;
-    default: break;
-  }
-  return rc;
-}
-#endif /* ifdef __EMSCRIPTEN__  (kvvfs method impls) */
 
 #undef WASM_KEEP

ext/wasm/index.html

@@ -39,6 +39,8 @@
         <li><a href='speedtest1.html'>speedtest1</a>: a main-thread WASM build of speedtest1.</li>
         <li><a href='speedtest1-worker.html'>speedtest1-worker</a>: an interactive Worker-thread variant of speedtest1.</li>
         <li><a href='demo-oo1.html'>demo-oo1</a>: demonstration of the OO API #1.</li>
+        <li><a href='kvvfs1.html'>kvvfs1</a>: very basic demo of using the key-value vfs for storing
+          a persistent db in JS localStorage or sessionStorage.</li>
         <!--li><a href='x.html'></a></li-->
       </ul>
     </div>

ext/wasm/kvvfs.make

@@ -0,0 +1,84 @@
+#!/usr/bin/make
+#^^^^ help emacs select makefile mode
+#
+# This is a sub-make for building a standalone kvvfs-based
+# sqlite3.wasm.  It is intended to be "include"d from the main
+# GNUMakefile.
+#
+# Notable potential TODOs:
+#
+# - Trim down a custom sqlite3-api.js for this build. We can elimate
+#   the jaccwabyt dependency, for example, because this build won't
+#   make use of the VFS bits. Similarly, we can eliminate or replace
+#   parts of the OO1 API, or provide a related API which manages
+#   singletons of the localStorage/sessionStorage instances.
+#
+########################################################################
+MAKEFILE.kvvfs := $(lastword $(MAKEFILE_LIST))
+
+kvvfs.js     := sqlite3-kvvfs.js
+kvvfs.wasm   := sqlite3-kvvfs.wasm
+kvvfs.wasm.c := $(dir.api)/sqlite3-wasm.c
+
+CLEAN_FILES += $(kvvfs.js) $(kvvfs.wasm)
+
+########################################################################
+# emcc flags for .c/.o/.wasm.
+kvvfs.flags =
+#kvvfs.flags += -v # _very_ loud but also informative about what it's doing
+
+########################################################################
+# emcc flags for .c/.o.
+kvvfs.cflags :=
+kvvfs.cflags += -std=c99 -fPIC -g
+kvvfs.cflags += -I. -I$(dir.top)
+kvvfs.cflags += -DSQLITE_OS_KV=1 $(SQLITE_OPT)
+
+########################################################################
+# emcc flags specific to building the final .js/.wasm file...
+kvvfs.jsflags := -fPIC
+kvvfs.jsflags += --no-entry
+kvvfs.jsflags += --minify 0
+kvvfs.jsflags += -sENVIRONMENT=web
+kvvfs.jsflags += -sMODULARIZE
+kvvfs.jsflags += -sSTRICT_JS
+kvvfs.jsflags += -sDYNAMIC_EXECUTION=0
+kvvfs.jsflags += -sNO_POLYFILL
+kvvfs.jsflags += -sEXPORTED_FUNCTIONS=@$(dir.api)/EXPORTED_FUNCTIONS.sqlite3-api
+kvvfs.jsflags += -sEXPORTED_RUNTIME_METHODS=FS,wasmMemory,allocateUTF8OnStack
+                                            # wasmMemory ==> for -sIMPORTED_MEMORY
+                                            # allocateUTF8OnStack ==> kvvfs internals
+kvvfs.jsflags += -sUSE_CLOSURE_COMPILER=0
+kvvfs.jsflags += -sIMPORTED_MEMORY
+#kvvfs.jsflags += -sINITIAL_MEMORY=13107200
+#kvvfs.jsflags += -sTOTAL_STACK=4194304
+kvvfs.jsflags += -sEXPORT_NAME=sqlite3InitModule
+kvvfs.jsflags += -sGLOBAL_BASE=4096 # HYPOTHETICALLY keep func table indexes from overlapping w/ heap addr.
+kvvfs.jsflags += --post-js=$(post-js.js)
+#kvvfs.jsflags += -sFILESYSTEM=0 # only for experimentation. sqlite3 needs the FS API
+#                                Perhaps the kvvfs build doesn't?
+#kvvfs.jsflags += -sABORTING_MALLOC
+kvvfs.jsflags += -sALLOW_MEMORY_GROWTH
+kvvfs.jsflags += -sALLOW_TABLE_GROWTH
+kvvfs.jsflags += -Wno-limited-postlink-optimizations
+# ^^^^^ it likes to warn when we have "limited optimizations" via the -g3 flag.
+kvvfs.jsflags += -sERROR_ON_UNDEFINED_SYMBOLS=0
+kvvfs.jsflags += -sLLD_REPORT_UNDEFINED
+#kvvfs.jsflags += --import-undefined
+kvvfs.jsflags += -sMEMORY64=0
+ifneq (0,$(enable_bigint))
+kvvfs.jsflags += -sWASM_BIGINT
+endif
+
+$(kvvfs.js): $(MAKEFILE) $(MAKEFILE.kvvfs) $(kvvfs.wasm.c) \
+    EXPORTED_FUNCTIONS.api \
+    $(post-js.js)
+	$(emcc.bin) -o $@ $(emcc_opt) $(emcc.flags) $(kvvfs.cflags) $(kvvfs.jsflags) $(kvvfs.wasm.c)
+	chmod -x $(kvvfs.wasm)
+ifneq (,$(wasm-strip))
+	$(wasm-strip) $(kvvfs.wasm)
+endif
+	@ls -la $@ $(kvvfs.wasm)
+
+kvvfs: $(kvvfs.js)
+all: kvvfs

ext/wasm/kvvfs1.html

@@ -0,0 +1,43 @@
+<!doctype html>
+<html lang="en-us">
+  <head>
+    <meta charset="utf-8">
+    <meta http-equiv="Content-Type" content="text/html; charset=utf-8">
+    <link rel="shortcut icon" href="data:image/x-icon;," type="image/x-icon">
+    <link rel="stylesheet" href="common/emscripten.css"/>
+    <link rel="stylesheet" href="common/testing.css"/>
+    <title>sqlite3-kvvfs.js tests</title>
+  </head>
+  <body>
+    <header id='titlebar'><span>sqlite3-kvvfs.js tests</span></header>
+    <!-- emscripten bits -->
+    <figure id="module-spinner">
+      <div class="spinner"></div>
+      <div class='center'><strong>Initializing app...</strong></div>
+      <div class='center'>
+        On a slow internet connection this may take a moment.  If this
+        message displays for "a long time", intialization may have
+        failed and the JavaScript console may contain clues as to why.
+      </div>
+    </figure>
+    <div class="emscripten" id="module-status">Downloading...</div>
+    <div class="emscripten">
+      <progress value="0" max="100" id="module-progress" hidden='1'></progress>  
+    </div><!-- /emscripten bits -->
+    <div>Everything on this page happens in the dev console. TODOs for this demo include,
+      but are not necessarily limited to:
+
+      <ul>
+        <li>UI controls to switch between localStorage and sessionStorage</li>
+        <li>Button to clear storage.</li>
+        <li>Button to dump the current db contents.</li>
+        <!--li></li-->
+      </ul>
+    </div>
+    <hr>
+    <div id='test-output'></div>
+    <script src="sqlite3-kvvfs.js"></script>
+    <script src="common/SqliteTestUtil.js"></script>
+    <script src="kvvfs1.js"></script>
+  </body>
+</html>

ext/wasm/kvvfs1.js

@@ -0,0 +1,73 @@
+/*
+  2022-09-12
+
+  The author disclaims copyright to this source code.  In place of a
+  legal notice, here is a blessing:
+
+  *   May you do good and not evil.
+  *   May you find forgiveness for yourself and forgive others.
+  *   May you share freely, never taking more than you give.
+
+  ***********************************************************************
+
+  A basic test script for sqlite3-kvvfs.wasm. This file must be run in
+  main JS thread and sqlite3-kvvfs.js must have been loaded before it.
+*/
+'use strict';
+(function(){
+  const T = self.SqliteTestUtil;
+  const toss = function(...args){throw new Error(args.join(' '))};
+  const debug = console.debug.bind(console);
+  const eOutput = document.querySelector('#test-output');
+  const log = console.log.bind(console)
+  const logHtml = function(...args){
+    log.apply(this, args);
+    const ln = document.createElement('div');
+    ln.append(document.createTextNode(args.join(' ')));
+    eOutput.append(ln);
+  };
+
+  const runTests = function(Module){
+    //log("Module",Module);
+    const sqlite3 = Module.sqlite3,
+          capi = sqlite3.capi,
+          oo = sqlite3.oo1,
+          wasm = capi.wasm;
+    log("Loaded module:",capi.sqlite3_libversion(), capi.sqlite3_sourceid());
+    log("Build options:",wasm.compileOptionUsed());
+    T.assert( 0 !== capi.sqlite3_vfs_find(null) );
+
+    const dbStorage = 1 ? ':sessionStorage:' : ':localStorage:';
+    /**
+       The names ':sessionStorage:' and ':localStorage:' are handled
+       via the DB class constructor, not the C level. In the C API,
+       the names "local" and "session" are the current (2022-09-12)
+       names for those keys, but that is subject to change.
+    */
+    const db = new oo.DB( dbStorage );
+    log("Storage backend:",db.filename /* note that the name was internally translated */);
+    try {
+      db.exec("create table if not exists t(a)");
+      if(undefined===db.selectValue("select a from t limit 1")){
+        log("New db. Populating. This DB will persist across page reloads.");
+        db.exec("insert into t(a) values(1),(2),(3)");
+      }else{
+        log("Found existing table data:");
+        db.exec({
+          sql: "select * from t order by a",
+          rowMode: 0,
+          callback: function(v){log(v)}
+        });
+      }
+    }finally{
+      db.close();
+    }
+    log("End of demo.");
+  };
+
+  sqlite3InitModule(self.sqlite3TestModule).then(function(theModule){
+    console.warn("Installing Emscripten module as global EM for dev console access.");
+    self.EM = theModule;
+    runTests(theModule);
+  });
+})();

main.mk

@@ -68,7 +68,7 @@ LIBOBJ+= vdbe.o parse.o \
          main.o malloc.o mem0.o mem1.o mem2.o mem3.o mem5.o \
          memdb.o memjournal.o \
          mutex.o mutex_noop.o mutex_unix.o mutex_w32.o \
-         notify.o opcodes.o os.o os_unix.o os_win.o \
+         notify.o opcodes.o os.o os_kv.o os_unix.o os_win.o \
          pager.o pcache.o pcache1.o pragma.o prepare.o printf.o \
          random.o resolve.o rowset.o rtree.o \
          select.o sqlite3rbu.o status.o stmt.o \
@@ -134,6 +134,7 @@ SRC = \
   $(TOP)/src/os.h \
   $(TOP)/src/os_common.h \
   $(TOP)/src/os_setup.h \
+  $(TOP)/src/os_kv.c \
   $(TOP)/src/os_unix.c \
   $(TOP)/src/os_win.c \
   $(TOP)/src/os_win.h \
@@ -411,6 +412,7 @@ TESTSRC2 = \
   $(TOP)/src/main.c \
   $(TOP)/src/mem5.c \
   $(TOP)/src/os.c \
+  $(TOP)/src/os_kv.c \
   $(TOP)/src/os_unix.c \
   $(TOP)/src/os_win.c \
   $(TOP)/src/pager.c \

manifest

@@ -1,9 +1,9 @@
-C Minor\scleanups\sand\sdocumentation\sin\sthe\swasm\spieces.
+C Merge\skv-vfs\sbranch\sinto\sfiddle-opfs\sbranch\sto\sadd\skvvfs-based\swasm\sbuild\sand\sdemo.
-D 2022-09-11T16:59:40.674
+D 2022-09-12T16:09:50.625
 F .fossil-settings/empty-dirs dbb81e8fc0401ac46a1491ab34a7f2c7c0452f2f06b54ebb845d024ca8283ef1
 F .fossil-settings/ignore-glob 35175cdfcf539b2318cb04a9901442804be81cd677d8b889fcc9149c21f239ea
 F LICENSE.md df5091916dbb40e6e9686186587125e1b2ff51f022cc334e886c19a0e9982724
-F Makefile.in 918d18842ba16dac5ebd5f7913aa8fb4f39879c881deced83362ed44a14ab4c6
+F Makefile.in 50e421194df031f669667fdb238c54959ecbea5a0b97dd3ed776cffbeea926d5
 F Makefile.linux-gcc f609543700659711fbd230eced1f01353117621dccae7b9fb70daa64236c5241
 F Makefile.msc d547a2fdba38a1c6cd1954977d0b0cc017f5f8fbfbc65287bf8d335808938016
 F README.md 8b8df9ca852aeac4864eb1e400002633ee6db84065bd01b78c33817f97d31f5e
@@ -474,21 +474,21 @@ F ext/userauth/user-auth.txt e6641021a9210364665fe625d067617d03f27b04
 F ext/userauth/userauth.c 7f00cded7dcaa5d47f54539b290a43d2e59f4b1eb5f447545fa865f002fc80cb
 F ext/wasm/EXPORTED_FUNCTIONS.fiddle db7a4602f043cf4a5e4135be3609a487f9f1c83f05778bfbdf93766be4541b96
 F ext/wasm/EXPORTED_RUNTIME_METHODS.fiddle a004bd5eeeda6d3b28d16779b7f1a80305bfe009dfc7f0721b042967f0d39d02
-F ext/wasm/GNUmakefile 18b80a063c684b0ca44b96221fc2c23647d0196f757c83c7a572b853562d8ac9
+F ext/wasm/GNUmakefile 6e642a0dc7ac43d9287e8f31c80ead469ddc7475a6d4ab7ac3b1feefcd4f7279
 F ext/wasm/README.md e1ee1e7c321c6a250bf78a84ca6f5882890a237a450ba5a0649c7a8399194c52
 F ext/wasm/api/EXPORTED_FUNCTIONS.sqlite3-api 1dfd067b3cbd9a49cb204097367cf2f8fe71b5a3b245d9d82a24779fd4ac2394
 F ext/wasm/api/EXPORTED_RUNTIME_METHODS.sqlite3-api 1ec3c73e7d66e95529c3c64ac3de2470b0e9e7fbf7a5b41261c367cf4f1b7287
 F ext/wasm/api/README.md d876597edd2b9542b6ea031adaaff1c042076fde7b670b1dc6d8a87b28a6631b
 F ext/wasm/api/post-js-footer.js b64319261d920211b8700004d08b956a6c285f3b0bba81456260a713ed04900c
 F ext/wasm/api/post-js-header.js 0e853b78db83cb1c06b01663549e0e8b4f377f12f5a2d9a4a06cb776c003880b
-F ext/wasm/api/sqlite3-api-cleanup.js 1a12e64060c2cb0defd34656a76a9b1d7ed58459c290249bb31567c806fd44de
+F ext/wasm/api/sqlite3-api-cleanup.js 101919ec261644e2f6f0a59952fd9612127b69ea99b493277b2789ea478f9b6b
 F ext/wasm/api/sqlite3-api-glue.js 2bf536a38cde324cf352bc2c575f8e22c6d204d667c0eda5a254ba45318914bc
-F ext/wasm/api/sqlite3-api-oo1.js b06a1ac982c7d433396b8304550ce1493a63671a3bf653c3b5646a9075e0ca41
+F ext/wasm/api/sqlite3-api-oo1.js a9d8892be246548a9978ace506d108954aa13eb5ce25332975c8377953804ff3
 F ext/wasm/api/sqlite3-api-opfs.js 011799db398157cbd254264b6ebae00d7234b93d0e9e810345f213a5774993c0
-F ext/wasm/api/sqlite3-api-prologue.js afd753be49ecba4b5bfc3e54929826a01eaf96ac2d8cec575d683e3c5bcc8464
+F ext/wasm/api/sqlite3-api-prologue.js 9e37ce4dfd74926d0df80dd7e72e33085db4bcee48e2c21236039be416a7dff2
 F ext/wasm/api/sqlite3-api-worker1.js d33062afa045fd4be01ba4abc266801807472558b862b30056211b00c9c347b4
 F ext/wasm/api/sqlite3-wasi.h 25356084cfe0d40458a902afb465df8c21fc4152c1d0a59b563a3fba59a068f9
-F ext/wasm/api/sqlite3-wasm.c ab8abf26708238a17840cad224bec1511efde6e5b182068f3abf079ba1d83ef6
+F ext/wasm/api/sqlite3-wasm.c bf4637cf28463cada4b25f09651943c7ece004b253ef39b7ab68eaa60662aa09
 F ext/wasm/batch-runner.html 23209ade7981acce7ecd79d6eff9f4c5a4e8b14ae867ac27cd89b230be640fa6
 F ext/wasm/batch-runner.js 2abd146d3e3a66128ac0a2cc39bfd01e9811c9511fa10ec927d6649795f1ee50
 F ext/wasm/common/SqliteTestUtil.js 529161a624265ba84271a52db58da022649832fa1c71309fb1e02cc037327a2b
@@ -501,11 +501,14 @@ F ext/wasm/fiddle/emscripten.css 3d253a6fdb8983a2ac983855bfbdd4b6fa1ff267c28d695
 F ext/wasm/fiddle/fiddle-worker.js bccf46045be8824752876f3eec01c223be0616ccac184bffd0024cfe7a3262b8
 F ext/wasm/fiddle/fiddle.html 550c5aafce40bd218de9bf26192749f69f9b10bc379423ecd2e162bcef885c08
 F ext/wasm/fiddle/fiddle.js 4ffcfc9a235beebaddec689a549e9e0dfad6dca5c1f0b41f03468d7e76480686
-F ext/wasm/index.html 4f635f986dbc7518280abe0ef537ba41682e35f160fac35a0745cf6c4d223b62
+F ext/wasm/index.html 5876ae0442bef5b37fec9a45ee0722798e47ef727723ada742d33554845afa6a
 F ext/wasm/jaccwabyt/jaccwabyt.js 0d7f32817456a0f3937fcfd934afeb32154ca33580ab264dab6c285e6dbbd215
 F ext/wasm/jaccwabyt/jaccwabyt.md 447cc02b598f7792edaa8ae6853a7847b8178a18ed356afacbdbf312b2588106
 F ext/wasm/jaccwabyt/jaccwabyt_test.c 39e4b865a33548f943e2eb9dd0dc8d619a80de05d5300668e9960fff30d0d36f
 F ext/wasm/jaccwabyt/jaccwabyt_test.exports 5ff001ef975c426ffe88d7d8a6e96ec725e568d2c2307c416902059339c06f19
+F ext/wasm/kvvfs.make dba616578bf91a76370a46494dd68a09c6dff5beb6d5561e2db65a27216e9630
+F ext/wasm/kvvfs1.html b8304cd5c7e7ec32c3b15521a95c322d6efdb8d22b3c4156123545dc54e07583
+F ext/wasm/kvvfs1.js a5075f98ffecd7d32348697db991fc61342d89aa20651034d1572af61890fb8b
 F ext/wasm/scratchpad-opfs-main.html 4565cf194e66188190d35f70e82553e2e2d72b9809b73c94ab67b8cfd14d2e0c
 F ext/wasm/scratchpad-opfs-main.js 69e960e9161f6412fd0c30f355d4112f1894d6609eb431e2d16d207d1380518e
 F ext/wasm/scratchpad-opfs-worker.html 66c1d15d678f3bd306373d76b61c6c8aef988f61f4a8dd40185d452f9c6d2bf5
@@ -528,7 +531,7 @@ F ext/wasm/testing2.js 25584bcc30f19673ce13a6f301f89f8820a59dfe044e0c4f2913941f4
 F install-sh 9d4de14ab9fb0facae2f48780b874848cbf2f895 x
 F ltmain.sh 3ff0879076df340d2e23ae905484d8c15d5fdea8
 F magic.txt 8273bf49ba3b0c8559cb2774495390c31fd61c60
-F main.mk 20801eed419dc58936ff9449b04041edbbbc0488a9fc683e72471dded050e0bb
+F main.mk b1b02927b2e0b73d025f93e388f2f7fba07614e972453983bddc65cd2bf33bb1
 F mkso.sh fd21c06b063bb16a5d25deea1752c2da6ac3ed83
 F mptest/config01.test 3c6adcbc50b991866855f1977ff172eb6d901271
 F mptest/config02.test 4415dfe36c48785f751e16e32c20b077c28ae504
@@ -571,7 +574,7 @@ F src/insert.c aea5361767817f917b0f0f647a1f0b1621bd858938ae6ae545c3b6b9814b798f
 F src/json.c 7749b98c62f691697c7ee536b570c744c0583cab4a89200fdd0fc2aa8cc8cbd6
 F src/legacy.c d7874bc885906868cd51e6c2156698f2754f02d9eee1bae2d687323c3ca8e5aa
 F src/loadext.c 853385cc7a604157e137585097949252d5d0c731768e16b044608e5c95c3614b
-F src/main.c 8983b4a316d7e09946dd731913aa41712f02e2b55cb5c6c92126ccfe2473244a
+F src/main.c e11267cdd380be68d95d4292666636a7f1dff5f17a395f3d55be910d7e9350fb
 F src/malloc.c b7a3430cbe91d3e8e04fc10c2041b3a19794e63556ad2441a13d8dadd9b2bafc
 F src/mem0.c 6a55ebe57c46ca1a7d98da93aaa07f99f1059645
 F src/mem1.c c12a42539b1ba105e3707d0e628ad70e611040d8f5e38cf942cee30c867083de
@@ -590,8 +593,9 @@ F src/notify.c 89a97dc854c3aa62ad5f384ef50c5a4a11d70fcc69f86de3e991573421130ed6
 F src/os.c 0eb831ba3575af5277e47f4edd14fdfc90025c67eb25ce5cda634518d308d4e9
 F src/os.h 1ff5ae51d339d0e30d8a9d814f4b8f8e448169304d83a7ed9db66a65732f3e63
 F src/os_common.h b2f4707a603e36811d9b1a13278bffd757857b85
-F src/os_setup.h 0dbaea40a7d36bf311613d31342e0b99e2536586
+F src/os_kv.c a188e92dac693b1c1b512d93b0c4dc85c1baad11e322b01121f87057996e4d11
-F src/os_unix.c 102f7e5c5b59c18ea3dbc929dc3be8acb3afc0e0b6ad572e032335c9c27f44f1
+F src/os_setup.h 0711dbc4678f3ac52d7fe736951b6384a0615387c4ba5135a4764e4e31f4b6a6
+F src/os_unix.c d6322b78130d995160bb9cfb7850678ad6838b08c1d13915461b33326a406c04
 F src/os_win.c e9454cb141908e8eef2102180bad353a36480612d5b736e4c2bd5777d9b25a34
 F src/os_win.h 7b073010f1451abe501be30d12f6bc599824944a
 F src/pager.c 6176d9752eb580419e8fef4592dc417a6b00ddfd43ee22f818819bf8840ceee8
@@ -612,7 +616,7 @@ F src/shell.c.in e7e7c2c69ae86c5ee9e8ad66227203d46ff6dce8700a1b1dababff01c71d33d
 F src/sqlite.h.in b9b7fd73239d94db20332bb6e504688001e5564b655e1318a4427a1caef4b99e
 F src/sqlite3.rc 5121c9e10c3964d5755191c80dd1180c122fc3a8
 F src/sqlite3ext.h a988810c9b21c0dc36dc7a62735012339dc76fc7ab448fb0792721d30eacb69d
-F src/sqliteInt.h 94e7fc2a5f0fa5d1f0af84513fd2d1c70a9f6e772556b9dfef16feee63291eae
+F src/sqliteInt.h 44eb45c25d379361ee1bd7fc49205471c6cb8a3727aed42372cf4716f653ebf2
 F src/sqliteLimit.h d7323ffea5208c6af2734574bae933ca8ed2ab728083caa117c9738581a31657
 F src/status.c 160c445d7d28c984a0eae38c144f6419311ed3eace59b44ac6dafc20db4af749
 F src/table.c 0f141b58a16de7e2fbe81c308379e7279f4c6b50eb08efeec5892794a0ba30d1
@@ -1956,7 +1960,7 @@ F tool/mkshellc.tcl df5d249617f9cc94d5c48eb0401673eb3f31f383ecbc54e8a13ca3dd97e8
 F tool/mksourceid.c 36aa8020014aed0836fd13c51d6dc9219b0df1761d6b5f58ff5b616211b079b9
 F tool/mkspeedsql.tcl a1a334d288f7adfe6e996f2e712becf076745c97
 F tool/mksqlite3c-noext.tcl 4f7cfef5152b0c91920355cbfc1d608a4ad242cb819f1aea07f6d0274f584a7f
-F tool/mksqlite3c.tcl eee7e9d9c58abb1045f6ed74ad95ad26e8d22be29fdc431deea5267fb3fa049c
+F tool/mksqlite3c.tcl 4fc26a9bfa0c4505b203d7ca0cf086e75ebcd4d63eb719c82f37e3fecdf23d37
 F tool/mksqlite3h.tcl 1f5e4a1dbbbc43c83cc6e74fe32c6c620502240b66c7c0f33a51378e78fc4edf
 F tool/mksqlite3internalh.tcl eb994013e833359137eb53a55acdad0b5ae1049b
 F tool/mkvsix.tcl b9e0777a213c23156b6542842c238479e496ebf5
@@ -2019,8 +2023,8 @@ F vsixtest/vsixtest.tcl 6a9a6ab600c25a91a7acc6293828957a386a8a93
 F vsixtest/vsixtest.vcxproj.data 2ed517e100c66dc455b492e1a33350c1b20fbcdc
 F vsixtest/vsixtest.vcxproj.filters 37e51ffedcdb064aad6ff33b6148725226cd608e
 F vsixtest/vsixtest_TemporaryKey.pfx e5b1b036facdb453873e7084e1cae9102ccc67a0
-P cdbf09fa1b0c93aeb3222a157de33a4688ae629c2b829ffff0f1f62364c5ae1c
+P 4e6ce329872eb733ba2f7f7879747c52761ae97790fd8ed169a25a79854cc3d9 e49682c5eac91958f143e639c5656ca54560d14f5805d514bf4aa0c206e63844
-R 9d278bdeb3b04c59e81ef94ad61886ea
+R f15733833cf5e73dce86b4365f218581
 U stephan
-Z 1e71f5bdda12caaeb1881e6b3d2fda00
+Z f2a01bf4c99986993a2e00b39e93be73
 # Remove this line to create a well-formed Fossil manifest.

manifest.uuid

@@ -1 +1 @@
-4e6ce329872eb733ba2f7f7879747c52761ae97790fd8ed169a25a79854cc3d9
+a7d8b26acd3c1ae344369e4d70804c0cab45272c0983cfd32d616a0a7b28acb9

src/main.c

@@ -4781,8 +4781,8 @@ int sqlite3_snapshot_open(
 */
 int sqlite3_snapshot_recover(sqlite3 *db, const char *zDb){
   int rc = SQLITE_ERROR;
-  int iDb;
 #ifndef SQLITE_OMIT_WAL
+  int iDb;
 
 #ifdef SQLITE_ENABLE_API_ARMOR
   if( !sqlite3SafetyCheckOk(db) ){

src/os_setup.h

@@ -20,38 +20,72 @@
 ** Figure out if we are dealing with Unix, Windows, or some other operating
 ** system.
 **
-** After the following block of preprocess macros, all of SQLITE_OS_UNIX,
+** After the following block of preprocess macros, all of 
-** SQLITE_OS_WIN, and SQLITE_OS_OTHER will defined to either 1 or 0.  One of
+**
-** the three will be 1.  The other two will be 0.
+**    SQLITE_OS_KV
+**    SQLITE_OS_OTHER
+**    SQLITE_OS_UNIX
+**    SQLITE_OS_WIN
+**
+** will defined to either 1 or 0. One of them will be 1. The others will be 0.
+** If none of the macros are initially defined, then select either
+** SQLITE_OS_UNIX or SQLITE_OS_WIN depending on the target platform.
+**
+** If SQLITE_OS_OTHER=1 is specified at compile-time, then the application
+** must provide its own VFS implementation together with sqlite3_os_init()
+** and sqlite3_os_end() routines.
 */
-#if defined(SQLITE_OS_OTHER)
+#if !defined(SQLITE_OS_KV) && !defined(SQLITE_OS_OTHER) && \
-#  if SQLITE_OS_OTHER==1
+       !defined(SQLITE_OS_UNIX) && !defined(SQLITE_OS_WIN)
-#    undef SQLITE_OS_UNIX
+#  if defined(_WIN32) || defined(WIN32) || defined(__CYGWIN__) || \
+          defined(__MINGW32__) || defined(__BORLANDC__)
+#    define SQLITE_OS_WIN 1
 #    define SQLITE_OS_UNIX 0
-#    undef SQLITE_OS_WIN
-#    define SQLITE_OS_WIN 0
 #  else
-#    undef SQLITE_OS_OTHER
+#    define SQLITE_OS_WIN 0
+#    define SQLITE_OS_UNIX 1
 #  endif
 #endif
-#if !defined(SQLITE_OS_UNIX) && !defined(SQLITE_OS_OTHER)
+#if SQLITE_OS_OTHER+1>1
+#  undef SQLITE_OS_KV
+#  define SQLITE_OS_KV 0
+#  undef SQLITE_OS_UNIX
+#  define SQLITE_OS_UNIX 0
+#  undef SQLITE_OS_WIN
+#  define SQLITE_OS_WIN 0
+#endif
+#if SQLITE_OS_KV+1>1
+#  undef SQLITE_OS_OTHER
 #  define SQLITE_OS_OTHER 0
-#  ifndef SQLITE_OS_WIN
+#  undef SQLITE_OS_UNIX
-#    if defined(_WIN32) || defined(WIN32) || defined(__CYGWIN__) || \
+#  define SQLITE_OS_UNIX 0
-        defined(__MINGW32__) || defined(__BORLANDC__)
+#  undef SQLITE_OS_WIN
-#      define SQLITE_OS_WIN 1
+#  define SQLITE_OS_WIN 0
-#      define SQLITE_OS_UNIX 0
+#  define SQLITE_OMIT_LOAD_EXTENSION 1
-#    else
+#  define SQLITE_OMIT_WAL 1
-#      define SQLITE_OS_WIN 0
+#  define SQLITE_OMIT DEPRECATED 1
-#      define SQLITE_OS_UNIX 1
+#  undef SQLITE_TEMP_STORE
-#    endif
+#  define SQLITE_TEMP_STORE 3  /* Always use memory for temporary storage */
-#  else
+#  define SQLITE_DQS 0
-#    define SQLITE_OS_UNIX 0
+#  define SQLITE_OMIT_SHARED_CACHE 1
-#  endif
+#  define SQLITE_OMIT_AUTOINIT 1
-#else
+#endif
-#  ifndef SQLITE_OS_WIN
+#if SQLITE_OS_UNIX+1>1
-#    define SQLITE_OS_WIN 0
+#  undef SQLITE_OS_KV
-#  endif
+#  define SQLITE_OS_KV 0
+#  undef SQLITE_OS_OTHER
+#  define SQLITE_OS_OTHER 0
+#  undef SQLITE_OS_WIN
+#  define SQLITE_OS_WIN 0
+#endif
+#if SQLITE_OS_WIN+1>1
+#  undef SQLITE_OS_KV
+#  define SQLITE_OS_KV 0
+#  undef SQLITE_OS_OTHER
+#  define SQLITE_OS_OTHER 0
+#  undef SQLITE_OS_UNIX
+#  define SQLITE_OS_UNIX 0
 #endif
 
+
 #endif /* SQLITE_OS_SETUP_H */

src/os_unix.c

@@ -87,11 +87,11 @@
 /*
 ** standard include files.
 */
-#include <sys/types.h>
+#include <sys/types.h>   /* amalgamator: keep */
-#include <sys/stat.h>
+#include <sys/stat.h>    /* amalgamator: keep */
 #include <fcntl.h>
 #include <sys/ioctl.h>
-#include <unistd.h>
+#include <unistd.h>      /* amalgamator: keep */
 #include <time.h>
 #include <sys/time.h>
 #include <errno.h>

src/sqliteInt.h

@@ -1268,11 +1268,11 @@ typedef int VList;
 ** "BusyHandler" typedefs. vdbe.h also requires a few of the opaque
 ** pointer types (i.e. FuncDef) defined above.
 */
+#include "os.h"
 #include "pager.h"
 #include "btree.h"
 #include "vdbe.h"
 #include "pcache.h"
-#include "os.h"
 #include "mutex.h"
 
 /* The SQLITE_EXTRA_DURABLE compile-time option used to set the default

tool/mksqlite3c.tcl

@@ -355,6 +355,7 @@ foreach file {
    hash.c
    opcodes.c
 
+   os_kv.c
    os_unix.c
    os_win.c
    memdb.c