# Build SQLite as a standalone WASM module for use with mcp-v8.
#
# Uses the SQLite autoconf source from nixpkgs (which includes the
# amalgamation sqlite3.c) and Emscripten to produce a WASI-compatible
# sqlite3.wasm that can be loaded with `--wasm-module sqlite=sqlite3.wasm`.
{ pkgs }:
pkgs.stdenv.mkDerivation {
pname = "sqlite3-wasm";
version = pkgs.sqlite.version;
# Re-use the SQLite autoconf source that nixpkgs already fetches.
# It contains the amalgamation (sqlite3.c / sqlite3.h) at the top level.
src = pkgs.sqlite.src;
nativeBuildInputs = [ pkgs.emscripten ];
buildPhase = ''
# Emscripten needs a writable cache directory
export EM_CACHE=$(mktemp -d)
# Copy the minimal in-memory VFS into the build directory
# (sqlite3.h is already here from the amalgamation source)
cp ${../examples/sqlite-wasm/memvfs.c} memvfs.c
emcc sqlite3.c memvfs.c \
-o sqlite3.wasm \
-O2 \
-sSTANDALONE_WASM=1 \
-sEXPORTED_FUNCTIONS='[
"_sqlite3_open",
"_sqlite3_close",
"_sqlite3_exec",
"_sqlite3_errmsg",
"_sqlite3_prepare_v2",
"_sqlite3_step",
"_sqlite3_column_count",
"_sqlite3_column_type",
"_sqlite3_column_int",
"_sqlite3_column_double",
"_sqlite3_column_text",
"_sqlite3_column_bytes",
"_sqlite3_column_name",
"_sqlite3_finalize",
"_sqlite3_changes",
"_sqlite3_last_insert_rowid",
"_malloc",
"_free"
]' \
-sERROR_ON_UNDEFINED_SYMBOLS=0 \
-sALLOW_MEMORY_GROWTH=1 \
-sINITIAL_MEMORY=16777216 \
-sSTACK_SIZE=65536 \
-sFILESYSTEM=0 \
--no-entry \
-DSQLITE_OS_OTHER=1 \
-DSQLITE_OMIT_LOAD_EXTENSION \
-DSQLITE_OMIT_WAL \
-DSQLITE_THREADSAFE=0 \
-DSQLITE_OMIT_LOCALTIME \
-DSQLITE_OMIT_RANDOMNESS \
-DSQLITE_TEMP_STORE=3 \
-DSQLITE_OMIT_DEPRECATED
'';
installPhase = ''
mkdir -p $out
cp sqlite3.wasm $out/sqlite3.wasm
'';
}
