1 files changed, 75 insertions, 0 deletions
diff --git a/packages/contract-wrappers/src/stores/order_filled_cancelled_lazy_store.ts b/packages/contract-wrappers/src/stores/order_filled_cancelled_lazy_store.ts
new file mode 100644
index 000000000..3d96a95f3
--- /dev/null
+++ b/packages/contract-wrappers/src/stores/order_filled_cancelled_lazy_store.ts
@@ -0,0 +1,75 @@
+import { AbstractOrderFilledCancelledFetcher } from '@0xproject/order-utils';
+import { BlockParamLiteral } from '@0xproject/types';
+import { BigNumber } from '@0xproject/utils';
+import * as _ from 'lodash';
+
+import { ExchangeWrapper } from '../contract_wrappers/exchange_wrapper';
+
+/**
+ * Copy on read store for filled/cancelled taker amounts
+ */
+export class OrderFilledCancelledLazyStore implements AbstractOrderFilledCancelledFetcher {
+    private _exchangeWrapper: ExchangeWrapper;
+    private _defaultBlock: BlockParamLiteral;
+    private _filledTakerAmount: {
+        [orderHash: string]: BigNumber;
+    };
+    private _cancelledTakerAmount: {
+        [orderHash: string]: BigNumber;
+    };
+    constructor(exchange: ExchangeWrapper, defaultBlock: BlockParamLiteral) {
+        this._exchangeWrapper = exchange;
+        this._defaultBlock = defaultBlock;
+        this._filledTakerAmount = {};
+        this._cancelledTakerAmount = {};
+    }
+    public async getFilledTakerAmountAsync(orderHash: string): Promise<BigNumber> {
+        if (_.isUndefined(this._filledTakerAmount[orderHash])) {
+            const methodOpts = {
+                defaultBlock: this._defaultBlock,
+            };
+            const filledTakerAmount = await this._exchangeWrapper.getFilledTakerAmountAsync(orderHash, methodOpts);
+            this.setFilledTakerAmount(orderHash, filledTakerAmount);
+        }
+        const cachedFilled = this._filledTakerAmount[orderHash];
+        return cachedFilled;
+    }
+    public setFilledTakerAmount(orderHash: string, filledTakerAmount: BigNumber): void {
+        this._filledTakerAmount[orderHash] = filledTakerAmount;
+    }
+    public deleteFilledTakerAmount(orderHash: string): void {
+        delete this._filledTakerAmount[orderHash];
+    }
+    public async getCancelledTakerAmountAsync(orderHash: string): Promise<BigNumber> {
+        if (_.isUndefined(this._cancelledTakerAmount[orderHash])) {
+            const methodOpts = {
+                defaultBlock: this._defaultBlock,
+            };
+            const cancelledTakerAmount = await this._exchangeWrapper.getCancelledTakerAmountAsync(
+                orderHash,
+                methodOpts,
+            );
+            this.setCancelledTakerAmount(orderHash, cancelledTakerAmount);
+        }
+        const cachedCancelled = this._cancelledTakerAmount[orderHash];
+        return cachedCancelled;
+    }
+    public setCancelledTakerAmount(orderHash: string, cancelledTakerAmount: BigNumber): void {
+        this._cancelledTakerAmount[orderHash] = cancelledTakerAmount;
+    }
+    public deleteCancelledTakerAmount(orderHash: string): void {
+        delete this._cancelledTakerAmount[orderHash];
+    }
+    public deleteAll(): void {
+        this._filledTakerAmount = {};
+        this._cancelledTakerAmount = {};
+    }
+    public async getUnavailableTakerAmountAsync(orderHash: string): Promise<BigNumber> {
+        const unavailableTakerAmount = await this._exchangeWrapper.getUnavailableTakerAmountAsync(orderHash);
+        return unavailableTakerAmount;
+    }
+    public getZRXTokenAddress(): string {
+        const zrxToken = this._exchangeWrapper.getZRXTokenAddress();
+        return zrxToken;
+    }
+}