Update wasmfs.make to get WASMFS building again, but changes made to OPFS-over-WASMFS since we last tested it have made it incompatible with how we used it. It can now only be used from worker threads, eliminating the one benefit it had over the sqlite3_vfs OPFS implementation. Remove/amend references to WASMFS in the docs and remove all WASMFS-specific test app links from index.html.

FossilOrigin-Name: 32dc98c8001387b1970623192ec6cb89445000fa49bda5f4bd7c525bbe20bb5b

1 files changed, 16 insertions, 7 deletions

diff --git a/ext/wasm/api/sqlite3-api-prologue.js b/ext/wasm/api/sqlite3-api-prologue.js
index ef0885cb9..94514e477 100644
--- a/ext/wasm/api/sqlite3-api-prologue.js
+++ b/ext/wasm/api/sqlite3-api-prologue.js
@@ -79,13 +79,9 @@
      the `realloc(3)`-compatible routine for the WASM
      environment. Defaults to `"sqlite3_realloc"`.
 
-   - `wasmfsOpfsDir`[^1]: if the environment supports persistent
-     storage using OPFS-over-WASMFS , this directory names the "mount
-     point" for that directory. It must be prefixed by `/` and may
-     contain only a single directory-name part. Using the root
-     directory name is not supported by any current persistent
-     backend.  This setting is only used in WASMFS-enabled builds.
-
+   - `wasmfsOpfsDir`[^1]: As of 2022-12-17, this feature does not
+     currently work due to incompatible Emscripten-side changes made
+     in the WASMFS+OPFS combination. This option is currently ignored.
 
    [^1] = This property may optionally be a function, in which case this
           function re-assigns it to the value returned from that function,
@@ -138,6 +134,10 @@ self.sqlite3ApiBootstrap = function sqlite3ApiBootstrap(
       config[k] = config[k]();
     }
   });
+  config.wasmOpfsDir =
+    /* 2022-12-17: WASMFS+OPFS can no longer be activated from the
+       main thread (aborts via a failed assert() if it's attempted),
+       which eliminates any(?) benefit to supporting it. */  false;
 
   /** 
       The main sqlite3 binding API gets installed into this object,
@@ -1050,6 +1050,13 @@ self.sqlite3ApiBootstrap = function sqlite3ApiBootstrap(
   /** State for sqlite3_wasmfs_opfs_dir(). */
   let __wasmfsOpfsDir = undefined;
   /**
+     2022-12-17: incompatible WASMFS changes have made WASMFS+OPFS
+     unavailable from the main thread, which eliminates the most
+     significant benefit of supporting WASMFS. This function is now a
+     no-op which always returns a falsy value. Before that change,
+     this function behaved as documented below (and how it will again
+     if we can find a compelling reason to support it).
+
      If the wasm environment has a WASMFS/OPFS-backed persistent
      storage directory, its path is returned by this function. If it
      does not then it returns "" (noting that "" is a falsy value).
@@ -1066,6 +1073,8 @@ self.sqlite3ApiBootstrap = function sqlite3ApiBootstrap(
     if(undefined !== __wasmfsOpfsDir) return __wasmfsOpfsDir;
     // If we have no OPFS, there is no persistent dir
     const pdir = config.wasmfsOpfsDir;
+    console.error("sqlite3_wasmfs_opfs_dir() can no longer work due "+
+                  "to incompatible WASMFS changes. It will be removed.");
     if(!pdir
        || !self.FileSystemHandle
        || !self.FileSystemDirectoryHandle