fpc/packages/wasmtime/examples/helloworld.pp
2023-10-30 09:17:01 +01:00

114 lines
3.2 KiB
ObjectPascal

{$mode objfpc}
{$h+}
program helloworld;
uses classes,ctypes, wasmtime;
procedure exit_with_error(message : PAnsiChar; error : Pwasmtime_error_t; trap: Pwasm_trap_t); cdecl;
var
error_message : Twasm_byte_vec_t ;
S : AnsiString;
begin
Writeln(stderr, 'error: ', message);
S:='';
if (error <> Nil) then
begin
wasmtime_error_message(error, @error_message);
wasmtime_error_delete(error)
end
else
begin
wasm_trap_message(trap, @error_message);
wasm_trap_delete(trap);
end;
SetLength(S,error_message.size);
Move(error_message.data^,S[1],error_message.size);
Writeln(stderr, S);
wasm_byte_vec_delete(@error_message);
halt(1);
end;
function hello_callback(env : Pointer; caller : Pwasmtime_caller_t; args : pwasmtime_val_t; nargs : size_t; results : pwasmtime_val_t; nresults : size_t) : pwasm_trap_t; cdecl;
begin
Writeln('Calling back...');
Writeln(' Hello World!');
Result:=Nil;
end;
Var
engine : Pwasm_engine_t = Nil;
store : Pwasmtime_store_t = Nil;
context : Pwasmtime_context_t = Nil;
F : TMemoryStream;
wat : Twasm_byte_vec_t;
wasm : twasm_byte_vec_t;
module : Pwasmtime_module_t = Nil;
error : Pwasmtime_error_t = Nil;
hello_ty : Pwasm_functype_t = nil;
hello : Twasmtime_func_t;
trap : Pwasm_trap_t = Nil;
instance : Twasmtime_instance_t;
import : Twasmtime_extern_t;
run : Twasmtime_extern_t;
ok : Byte;
begin
Writeln('Loading wasm library');
Loadwasmtime('./'+libwasmtime);
Writeln('Initializing...');
engine := wasm_engine_new();
store:=wasmtime_store_new(engine, nil,nil);
context:=wasmtime_store_context(store);
F:=TMemoryStream.Create;
try
F.LoadFromFile('hello.wat');
wasm_byte_vec_new_uninitialized(@wat, F.Size);
Move(F.Memory^,wat.data^,F.Size);
finally
F.Free;
end;
error:=wasmtime_wat2wasm(PAnsiChar(wat.data), wat.size, @wasm);
if (error<>Nil) then
exit_with_error('failed to parse wat', error, Nil);
wasm_byte_vec_delete(@wat);
Writeln('Compiling module...');
error:=wasmtime_module_new(engine, Puint8_t(wasm.data), wasm.size, @module);
wasm_byte_vec_delete(@wasm);
if (error <> nil) then
exit_with_error('failed to compile module', error, nil);
Writeln('Creating callback...');
hello_ty:=wasm_functype_new_0_0();
wasmtime_func_new(context, hello_ty, @hello_callback, Nil, Nil, @hello);
Writeln('Instantiating module...');
import.kind:=WASMTIME_EXTERN_FUNC;
import.of_.func:=hello;
error:=wasmtime_instance_new(context, module, @import, 1, @instance, @trap);
if (error<>nil) or (trap <>Nil) then
exit_with_error('failed to instantiate', error, trap);
Writeln('Extracting export...');
ok:=wasmtime_instance_export_get(context, @instance, PAnsiChar('run'), 3, @run) ;
if OK=0 then
exit_with_error('failed to get run export', nil, nil);
if run.kind<>WASMTIME_EXTERN_FUNC then
exit_with_error('run is not a function', nil, nil);
Writeln('Calling export...');
error:=wasmtime_func_call(context, @run.of_.func, nil, 0, nil, 0, @trap);
if (error<>nil) or (trap<>nil) then
exit_with_error('failed to call function', error, trap);
Writeln('All finished!');
wasmtime_module_delete(module);
wasmtime_store_delete(store);
wasm_engine_delete(engine);
end.