wip: sql normalized disk cache

lib/src/cache/cache.dart

@@ -1,5 +1,6 @@
 abstract class Cache {
   dynamic read(String key) {}
+  Future<bool> remove(String key, bool cascade) async {}
   void write(
     String key,
     dynamic value,

lib/src/cache/in_memory.dart

@@ -102,4 +102,10 @@ class InMemoryCache implements Cache {
       return HashMap<String, dynamic>();
     }
   }
+
+  @override
+  Future<bool> remove(String key, bool cascade) {
+    // TODO: implement remove
+    return null;
+  }
 }

lib/src/cache/normalized/record_field_json_adapter.dart

@@ -0,0 +1,77 @@
+import 'dart:core';
+
+class RecordFieldJsonAdapter {
+
+  static RecordFieldJsonAdapter create() {
+    return new RecordFieldJsonAdapter();
+  }
+
+  RecordFieldJsonAdapter() {
+  }
+
+  /* String toJson(Map<String, Object> fields) {
+    checkNotNull(fields, "fields == null");
+    Buffer buffer = new Buffer();
+    JsonWriter jsonWriter = JsonWriter.of(buffer);
+    jsonWriter.setSerializeNulls(true);
+
+    try {
+      jsonWriter.beginObject();
+      for (Map.Entry<String, Object> fieldEntry : fields.entrySet()) {
+        String key = fieldEntry.getKey();
+        Object value = fieldEntry.getValue();
+        jsonWriter.name(key);
+        writeJsonValue(value, jsonWriter);
+      }
+      jsonWriter.endObject();
+      jsonWriter.close();
+      return buffer.readUtf8();
+    } catch (IOException e) {
+      // should never happen as we are working with mem buffer
+      throw new RuntimeException(e);
+    }
+  }
+
+  private Map<String, Object> fromBufferSource(BufferedSource bufferedFieldSource) throws IOException {
+    final CacheJsonStreamReader cacheJsonStreamReader =
+        cacheJsonStreamReader(bufferedSourceJsonReader(bufferedFieldSource));
+    return cacheJsonStreamReader.toMap();
+  }
+
+  public Map<String, Object> from(String jsonFieldSource) throws IOException {
+    final BufferedSource bufferSource
+        = Okio.buffer(Okio.source(new ByteArrayInputStream(jsonFieldSource.getBytes(Charset.defaultCharset()))));
+    return fromBufferSource(bufferSource);
+  }
+
+  private static void writeJsonValue(Object value, JsonWriter jsonWriter) throws IOException {
+    if (value == null) {
+      jsonWriter.nullValue();
+    } else if (value instanceof String) {
+      jsonWriter.value((String) value);
+    } else if (value instanceof Boolean) {
+      jsonWriter.value((boolean) value);
+    } else if (value instanceof Number) {
+      jsonWriter.value((Number) value);
+    } else if (value instanceof CacheReference) {
+      jsonWriter.value(((CacheReference) value).serialize());
+    } else if (value instanceof List) {
+      jsonWriter.beginArray();
+      for (Object item : (List) value) {
+        writeJsonValue(item, jsonWriter);
+      }
+      jsonWriter.endArray();
+    } else if (value instanceof Map) {
+      //noinspection unchecked
+      Map<String, Object> fields = (Map) value;
+      jsonWriter.beginObject();
+      for (Map.Entry<String, Object> fieldEntry : fields.entrySet()) {
+        jsonWriter.name(fieldEntry.getKey());
+        writeJsonValue(fieldEntry.getValue(), jsonWriter);
+      }
+      jsonWriter.endObject();
+    } else {
+      throw new RuntimeException("Unsupported record value type: " + value.getClass());
+    }
+  } */
+}

lib/src/cache/normalized/sql/sql-normalized-cache.dart

@@ -0,0 +1,61 @@
+import 'package:flutter_graphql/src/cache/cache.dart';
+import 'package:flutter_graphql/src/cache/normalized/sql/sql_helper.dart';
+import 'package:sqflite/sqflite.dart';
+
+class SqlNormalizedCache implements Cache {
+
+  static const String INSERT_STATEMENT = '''INSERT INTO ${SqlHelper.TABLE_RECORDS} (${SqlHelper.COLUMN_KEY},${SqlHelper.COLUMN_RECORD}) VALUES (?,?)''';
+  static const String UPDATE_STATEMENT = '''UPDATE ${SqlHelper.TABLE_RECORDS} SET ${SqlHelper.COLUMN_KEY}=?, ${SqlHelper.COLUMN_RECORD}=? WHERE ${SqlHelper.COLUMN_KEY}=?''';
+
+  static const String DELETE_STATEMENT = '''DELETE FROM ${SqlHelper.TABLE_RECORDS} WHERE ${SqlHelper.COLUMN_KEY}=?''';
+  static const String DELETE_ALL_RECORD_STATEMENT = '''DELETE FROM ${SqlHelper.TABLE_RECORDS}''';
+
+  Database database;
+  final SqlHelper dbHelper;
+  final allColumns = [
+      SqlHelper.COLUMN_ID,
+      SqlHelper.COLUMN_KEY,
+      SqlHelper.COLUMN_RECORD];
+
+  SqlNormalizedCache(this.dbHelper);
+
+  /*
+  private final SQLiteStatement insertStatement;
+  private final SQLiteStatement updateStatement;
+  private final SQLiteStatement deleteStatement;
+  private final SQLiteStatement deleteAllRecordsStatement;
+  private final RecordFieldJsonAdapter recordFieldAdapter;*/
+
+  @override
+  Object read(String key) {
+    // TODO: implement read
+    return null;
+  }
+
+  @override
+  void reset() {
+    // TODO: implement reset
+  }
+
+  @override
+  void restore() {
+    // TODO: implement restore
+  }
+
+  @override
+  void save() {
+    // TODO: implement save
+  }
+
+  @override
+  void write(String key, value) {
+    // TODO: implement write
+  }
+
+  @override
+  Future<bool> remove(String key, bool cascade) {
+    // TODO: implement remove
+    return null;
+  }
+
+}

lib/src/cache/normalized/sql/sql_helper.dart

@@ -0,0 +1,33 @@
+import 'package:path/path.dart';
+import 'package:sqflite/sqflite.dart';
+
+class SqlHelper {
+
+  static const String TABLE_RECORDS = 'records';
+  static const String COLUMN_ID = '_id';
+  static const String COLUMN_RECORD = 'record';
+  static const String COLUMN_KEY = 'key';
+
+  static const String DATABASE_NAME = 'graphql-flutter.db';
+  static const int DATABASE_VERSION = 1;
+
+  static const String DATABASE_CREATE = '''CREATE TABLE $TABLE_RECORDS ($COLUMN_ID INTEGER PRIMARY KEY AUTOINCREMENT, $COLUMN_KEY TEXT NOT NULL, $COLUMN_RECORD TEXT NOT NULL''';
+  static const String IDX_RECORDS_KEY = 'idx_records_key';
+  static const String CREATE_KEY_INDEX = '''CREATE INDEX $IDX_RECORDS_KEY ON $TABLE_RECORDS ($COLUMN_KEY)''';
+
+  Database db;
+
+  Future open() async {
+    final databasesPath = await getDatabasesPath();
+    String path = join(databasesPath, DATABASE_NAME);
+    db = await openDatabase(path, version: DATABASE_VERSION, onCreate: (Database db, int version) async {
+      await db.execute(DATABASE_CREATE);
+      await db.execute(CREATE_KEY_INDEX);
+    });
+  }
+
+  Future close() async {
+    await db.close();
+  }
+
+}

pubspec.yaml

@@ -16,6 +16,7 @@ dependencies:
   path_provider: ^0.4.1
   uuid: ^1.0.3
   graphql_parser: ^1.1.1
+  sqflite: ^1.1.0
 
 dev_dependencies:
   flutter_test: