Skip to content

Instantly share code, notes, and snippets.

@corusm

corusm/main.dart

Created July 6, 2021 22:06
Show Gist options
  • Save corusm/9636f43d6f9211cfce67536b7755d3d2 to your computer and use it in GitHub Desktop.
Save corusm/9636f43d6f9211cfce67536b7755d3d2 to your computer and use it in GitHub Desktop.
Download ZIP
Automerge Dart FFI
Raw
main.dart
import 'dart:ffi';
import 'dart:io';
import 'package:ffi/ffi.dart';
import 'package:path/path.dart' as path;
import 'dart:convert' show jsonDecode, jsonEncode, utf8;
class Backend extends Opaque {}
typedef _automerge_apply_changes = IntPtr Function(Pointer<Backend>);
typedef AutomergeApplyChanges = int Function(Pointer<Backend>);
typedef _automerge_apply_local_change = IntPtr Function(
Pointer<Backend>, Pointer<Utf8>);
typedef AutomergeApplyLocalChange = int Function(
Pointer<Backend>, Pointer<Utf8>);
typedef _automerge_clone = Pointer<Backend> Function(Pointer<Backend>);
typedef AutomergeClone = Pointer<Backend> Function(Pointer<Backend>);
typedef _automerge_decode_change = IntPtr Function(
Pointer<Backend>, IntPtr, Pointer<Uint8>);
typedef AutomergeDecodeChange = int Function(
Pointer<Backend>, int, Pointer<Uint8>);
typedef _automerge_encode_change = IntPtr Function(
Pointer<Backend>, Pointer<Uint8>);
typedef AutomergeEncodeChange = int Function(Pointer<Backend>, Pointer<Uint8>);
typedef _automerge_error = Pointer<Utf8> Function(Pointer<Backend>);
typedef AutomergeError = Pointer<Utf8> Function(Pointer<Backend>);
typedef _automerge_free = Void Function(Pointer<Backend>);
typedef AutomergeFree = void Function(Pointer<Backend>);
typedef _automerge_get_changes_for_actor = IntPtr Function(
Pointer<Backend>, Pointer<Utf8>);
typedef AutomergeGetChangesForActor = int Function(
Pointer<Backend>, Pointer<Utf8>);
typedef _automerge_get_heads = IntPtr Function(Pointer<Backend>);
typedef AutomergeGetHeads = int Function(Pointer<Backend>);
typedef _automerge_get_last_local_change = IntPtr Function(Pointer<Backend>);
typedef AutomergeGetLastLocalChange = int Function(Pointer<Backend>);
typedef _automerge_get_missing_deps = IntPtr Function(Pointer<Backend>);
typedef AutomergeGetMissingDeps = int Function(Pointer<Backend>);
typedef _automerge_get_patch = IntPtr Function(Pointer<Backend>);
typedef AutomergeGetPatch = int Function(Pointer<Backend>);
typedef _automerge_init = Pointer<Backend> Function();
typedef AutomergeInit = Pointer<Backend> Function();
typedef _automerge_load = Pointer<Backend> Function(IntPtr, Pointer<Uint8>);
typedef AutomergeLoad = Pointer<Backend> Function(int, Pointer<Uint8>);
typedef _automerge_load_changes = IntPtr Function(Pointer<Backend>);
typedef AutomergeLoadChanges = int Function(Pointer<Backend>);
typedef _automerge_read_binary = IntPtr Function(
Pointer<Backend>, Pointer<Uint8>);
typedef AutomergeReadBinary = int Function(Pointer<Backend>, Pointer<Uint8>);
typedef _automerge_read_json = IntPtr Function(
Pointer<Backend>, Pointer<Uint8>);
typedef AutomergeReadJSON = int Function(Pointer<Backend>, Pointer<Uint8>);
typedef _automerge_save = IntPtr Function(Pointer<Backend>);
typedef AutomergeSave = int Function(Pointer<Backend>);
typedef _automerge_write_change = Void Function(
Pointer<Backend>, IntPtr, Pointer<Uint8>);
typedef AutomergeWriteChange = void Function(
Pointer<Backend>, int, Pointer<Uint8>);
class Automerge {
late final AutomergeApplyChanges applyChanges;
late final AutomergeApplyLocalChange applyLocalChange;
late final AutomergeClone clone;
late final AutomergeDecodeChange decodeChange;
late final AutomergeEncodeChange encodeChange;
late final AutomergeError error;
late final AutomergeFree free;
late final AutomergeGetChangesForActor getChangesForActor;
late final AutomergeGetHeads getHeads;
late final AutomergeGetMissingDeps getMissingDeps;
late final AutomergeGetPatch getPatch;
late final AutomergeGetLastLocalChange getLastLocalChange;
late final AutomergeInit init;
late final AutomergeLoad load;
late final AutomergeLoadChanges loadChanges;
late final AutomergeReadBinary readBinary;
late final AutomergeReadJSON readJSON;
late final AutomergeSave save;
late final AutomergeWriteChange writeChange;
Automerge({DynamicLibrary? lib}) {
DynamicLibrary dylib = lib ?? loadLibrary();
applyChanges = dylib
.lookup<NativeFunction<_automerge_apply_changes>>(
'automerge_apply_changes')
.asFunction();
applyLocalChange = dylib
.lookup<NativeFunction<_automerge_apply_local_change>>(
'automerge_apply_local_change')
.asFunction();
clone = dylib
.lookup<NativeFunction<_automerge_clone>>('automerge_clone')
.asFunction();
decodeChange = dylib
.lookup<NativeFunction<_automerge_decode_change>>(
'automerge_decode_change')
.asFunction();
encodeChange = dylib
.lookup<NativeFunction<_automerge_encode_change>>(
'automerge_encode_change')
.asFunction();
error = dylib
.lookup<NativeFunction<_automerge_error>>('automerge_error')
.asFunction();
free = dylib
.lookup<NativeFunction<_automerge_free>>('automerge_free')
.asFunction();
getChangesForActor = dylib
.lookup<NativeFunction<_automerge_get_changes_for_actor>>(
'automerge_get_changes_for_actor')
.asFunction();
getHeads = dylib
.lookup<NativeFunction<_automerge_get_heads>>('automerge_get_heads')
.asFunction();
getLastLocalChange = dylib
.lookup<NativeFunction<_automerge_get_last_local_change>>(
'automerge_get_last_local_change')
.asFunction();
getMissingDeps = dylib
.lookup<NativeFunction<_automerge_get_missing_deps>>(
'automerge_get_missing_deps')
.asFunction();
getPatch = dylib
.lookup<NativeFunction<_automerge_get_patch>>('automerge_get_patch')
.asFunction();
init = dylib
.lookup<NativeFunction<_automerge_init>>('automerge_init')
.asFunction();
load = dylib
.lookup<NativeFunction<_automerge_load>>('automerge_load')
.asFunction();
loadChanges = dylib
.lookup<NativeFunction<_automerge_load_changes>>(
'automerge_load_changes')
.asFunction();
readBinary = dylib
.lookup<NativeFunction<_automerge_read_binary>>('automerge_read_binary')
.asFunction();
readJSON = dylib
.lookup<NativeFunction<_automerge_read_json>>('automerge_read_json')
.asFunction();
save = dylib
.lookup<NativeFunction<_automerge_save>>('automerge_save')
.asFunction();
writeChange = dylib
.lookup<NativeFunction<_automerge_write_change>>(
'automerge_write_change')
.asFunction();
}
DynamicLibrary loadLibrary() {
final libraryPath = path.join(
Directory.current.path, 'automerge_dart', 'lib', 'libautomerge.so');
return DynamicLibrary.open(libraryPath);
}
}
class DartAutomerge {
// Class variables
late Automerge automerge;
static const buffSize = 4096;
late Pointer<Uint8> buff;
late Pointer<Uint8> buff2;
late Pointer<Uint8> buff3;
late Pointer<Backend> pointerBackend;
DartAutomerge() {
automerge = Automerge();
const buffSize = 4096;
buff = malloc<Uint8>(buffSize);
buff2 = malloc<Uint8>(buffSize);
buff3 = malloc<Uint8>(buffSize);
pointerBackend = automerge.init();
}
/// Get Last change
String getLastLocalChange() {
final len = automerge.getLastLocalChange(pointerBackend);
if (len == -1) {
final err = automerge.error(pointerBackend);
return err.toDartString();
} else if (len > 0 && len < buffSize) {
final code = automerge.readBinary(pointerBackend, buff);
return code.toString();
} else {
return "error";
}
}
/// Apply local change
Map<String, dynamic> applyLocalChange(Map<String, dynamic> json) {
String jsonString = jsonEncode(json);
final len =
automerge.applyLocalChange(pointerBackend, jsonString.toNativeUtf8());
if (len == -1) {
final err = automerge.error(pointerBackend);
print("*** patchA2 expected error string ** (${err.toDartString()})\n");
return json;
} else if (len < buffSize) {
final code = automerge.readJSON(pointerBackend, buff);
if (code == 0) {
print("err1");
return json;
}
return jsonDecode(utf8.decode(buff.asTypedList(len - 1)));
} else {
print("err2");
return json;
}
}
/// Clone client to current
void clone(DartAutomerge client) {
Pointer<Backend> pointer2 = client.pointerBackend;
pointerBackend = automerge.clone(pointer2);
}
// Get Patch of two pointers -- equal??
bool getPatch(DartAutomerge client) {
Pointer<Backend> pointer2 = client.pointerBackend;
// Get Patch of A
final lenA = automerge.getPatch(pointerBackend);
late int codeA;
if (lenA < buffSize) {
codeA = automerge.readJSON(pointerBackend, buff);
if (codeA != 0) {
throw ("err");
}
}
// Get Patch of B
final lenB = automerge.getPatch(pointer2);
late int codeB;
if (lenB <= buffSize) {
codeB = automerge.readJSON(pointer2, buff2);
if (codeB != 0) {
print("err 2");
// throw ("err");
}
}
if (codeA == codeB) {
return true;
} else {
return false;
}
}
/// Free Buffer
void free() {
automerge.free(pointerBackend);
}
}
main() {
final automerge = Automerge();
final a1 =
'{"actor":"111111","seq":1,"time":0,"deps":[],"startOp":1,"ops":[{"action":"set","obj":"_root","key":"bird","value":"magpie","pred":[]}]}';
final a2 =
'{"actor":"111111","seq":2,"time":0,"deps":[],"startOp":2,"ops":[{"action":"set","obj":"_root","key":"dog","value":"mastiff","pred":[]}]}';
final b1 =
'{"actor":"222222","seq":1,"time":0,"deps":[],"startOp":1,"ops":[{"action":"set","obj":"_root","key":"bird","value":"crow","pred":[]}]}';
final b2 =
'{"actor":"222222","seq":2,"time":0,"deps":[],"startOp":2,"ops":[{"action":"set","obj":"_root","key":"cat","value":"tabby","pred":[]}]}';
const buffSize = 4096;
final buff = malloc<Uint8>(buffSize);
final buff2 = malloc<Uint8>(buffSize);
final buff3 = malloc<Uint8>(buffSize);
final dbA = automerge.init();
final dbB = automerge.init();
print("*** requestA1 ***\n\n${a1}\n");
{
final len = automerge.getLastLocalChange(dbA);
assert(len == -1);
final err = automerge.error(dbA);
print("*** last_local expected error string ** (${err.toDartString()})\n");
}
{
final len = automerge.applyLocalChange(dbA, a1.toNativeUtf8());
assert(len < buffSize);
final code = automerge.readJSON(dbA, buff);
assert(code == 0);
final s = utf8.decode(buff.asTypedList(len - 1));
print("*** patchA1 ***\n\n${s}\n");
}
{
final len = automerge.getLastLocalChange(dbA);
assert(len > 0);
assert(len < buffSize);
final code = automerge.readBinary(dbA, buff);
assert(code == 0);
}
{
final len = automerge.applyLocalChange(dbA, "{}".toNativeUtf8());
assert(len == -1);
final err = automerge.error(dbA);
print("*** patchA2 expected error string ** (${err.toDartString()})\n");
}
{
final len = automerge.applyLocalChange(dbA, a2.toNativeUtf8());
assert(len < buffSize);
final code = automerge.readJSON(dbA, buff);
assert(code == 0);
var s = utf8.decode(buff.asTypedList(len - 1));
print("*** patchA2 ***\n\n${s}\n");
}
{
final len = automerge.applyLocalChange(dbB, b1.toNativeUtf8());
assert(len < buffSize);
final code = automerge.readJSON(dbB, buff);
assert(code == 0);
var s = utf8.decode(buff.asTypedList(len - 1));
print("*** patchB1 ***\n\n${s}\n");
}
{
final len = automerge.applyLocalChange(dbB, b2.toNativeUtf8());
assert(len < buffSize);
final code = automerge.readJSON(dbB, buff);
assert(code == 0);
var s = utf8.decode(buff.asTypedList(len - 1));
print("*** patchB2 ***\n\n${s}\n");
}
print("*** clone dbA -> dbC ***\n");
final dbC = automerge.clone(dbA);
{
final lenA = automerge.getPatch(dbA);
assert(lenA < buffSize);
final codeA = automerge.readJSON(dbA, buff);
assert(codeA == 0);
final lenC = automerge.getPatch(dbC);
assert(lenC <= buffSize);
final codeC = automerge.readJSON(dbC, buff2);
assert(codeC == 0);
print("*** get_patch of dbA & dbC -- equal? *** --> ${codeA == codeC}\n");
assert(codeA == codeC);
}
Pointer<Backend> dbD;
{
final len = automerge.save(dbA);
assert(len <= buffSize);
final code = automerge.readBinary(dbA, buff2);
assert(code == 0);
print("*** save dbA - ${len} bytes ***\n");
final lenA = automerge.getPatch(dbA);
assert(lenA <= buffSize);
print("*** load the save into dbD ***\n");
dbD = automerge.load(len, buff2);
final lenD = automerge.getPatch(dbD);
assert(lenD <= buffSize);
final codeD = automerge.readJSON(dbD, buff2);
assert(codeD == 0);
print("*** get_patch of dbA & dbD -- equal? *** --> ${lenA == lenD}\n");
assert(lenA == lenD);
}
{
print("*** copy changes from dbA to B ***\n");
int len = automerge.getChangesForActor(dbA, "111111".toNativeUtf8());
print('getChangesForActor -> ${len}');
while (len > 0) {
assert(len <= buffSize);
final nextLen = automerge.readBinary(dbA, buff);
print('readBinary -> ${nextLen}');
automerge.writeChange(dbB, len, buff);
final decodeLen = automerge.decodeChange(dbB, len, buff);
print('decodeLen->${decodeLen}');
final code = automerge.readJSON(dbA, buff2);
assert(code == 0);
final s = utf8.decode(buff2.asTypedList(decodeLen - 1));
print("Change decoded to json -- ${s}");
automerge.encodeChange(dbB, buff2);
final codeB = automerge.readBinary(dbB, buff3);
assert(codeB == 0);
len = nextLen;
}
{
final code = automerge.applyChanges(dbB);
assert(code == 0);
}
// printf("*** load the save into dbD ***\n\n");
// Backend * dbD = automerge_load(len, buff2);
// len = automerge_get_patch(dbD);
// assert(len <= BUFSIZE);
// automerge_read_json(dbD, buff2);
// printf("*** get_patch of dbA & dbD -- equal? *** --> %s\n\n",strlen(buff) == strlen(buff2) ? "true" : "false");
// assert(strlen(buff) == strlen(buff2));
}
automerge.free(dbA);
automerge.free(dbB);
automerge.free(dbC);
}
Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment