Final rounds on evm data types

4 files changed, 59 insertions, 42 deletions

diff --git a/packages/utils/src/abi_encoder/evm_data_types/static_bytes.ts b/packages/utils/src/abi_encoder/evm_data_types/static_bytes.ts
index 9a2a99ec7..afa9afdf2 100644
--- a/packages/utils/src/abi_encoder/evm_data_types/static_bytes.ts
+++ b/packages/utils/src/abi_encoder/evm_data_types/static_bytes.ts
@@ -11,7 +11,6 @@ export class StaticBytes extends PayloadDataType {
     private static readonly _matcher = RegExp(
         '^(byte|bytes(1|2|3|4|5|6|7|8|9|10|11|12|13|14|15|16|17|18|19|20|21|22|23|24|25|26|27|28|29|30|31|32))$',
     );
-
     private static readonly _DEFAULT_WIDTH = 1;
     private readonly _width: number;
 
@@ -19,16 +18,20 @@ export class StaticBytes extends PayloadDataType {
         return StaticBytes._matcher.test(type);
     }
 
+    private static _decodeWidthFromType(type: string): number {
+        const matches = StaticBytes._matcher.exec(type);
+        const width = (matches !== null && matches.length === 3 && matches[2] !== undefined)
+            ? parseInt(matches[2], Constants.DEC_BASE)
+            : StaticBytes._DEFAULT_WIDTH;
+        return width;
+    }
+
     public constructor(dataItem: DataItem, dataTypeFactory: DataTypeFactory) {
         super(dataItem, dataTypeFactory, StaticBytes._SIZE_KNOWN_AT_COMPILE_TIME);
-        const matches = StaticBytes._matcher.exec(dataItem.type);
         if (!StaticBytes.matchType(dataItem.type)) {
-            throw new Error(`Tried to instantiate Byte with bad input: ${dataItem}`);
+            throw new Error(`Tried to instantiate Static Bytes with bad input: ${dataItem}`);
         }
-        this._width =
-            matches !== null && matches.length === 3 && matches[2] !== undefined
-                ? parseInt(matches[2], Constants.DEC_BASE)
-                : StaticBytes._DEFAULT_WIDTH;
+        this._width = StaticBytes._decodeWidthFromType(dataItem.type);
     }
 
     public getSignature(): string {
@@ -37,11 +40,30 @@ export class StaticBytes extends PayloadDataType {
     }
 
     public encodeValue(value: string | Buffer): Buffer {
-        // Sanity check if string
-        if (typeof value === 'string' && !value.startsWith('0x')) {
-            throw new Error(`Tried to encode non-hex value. Value must inlcude '0x' prefix.`);
+        // 1/2 Convert value into a buffer and do bounds checking
+        this._sanityCheckValue(value);
+        const valueBuf = ethUtil.toBuffer(value);
+        // 2/2 Store value as hex
+        const valuePadded = ethUtil.setLengthRight(valueBuf, Constants.EVM_WORD_WIDTH_IN_BYTES);
+        return valuePadded;
+    }
+
+    public decodeValue(calldata: RawCalldata): string {
+        const valueBufPadded = calldata.popWord();
+        const valueBuf = valueBufPadded.slice(0, this._width);
+        const value = ethUtil.bufferToHex(valueBuf);
+        this._sanityCheckValue(value);
+        return value;
+    }
+    
+    private _sanityCheckValue(value: string | Buffer): void {
+        if (typeof value === 'string') {
+            if (!value.startsWith('0x')) {
+                throw new Error(`Tried to encode non-hex value. Value must inlcude '0x' prefix.`);
+            } else if (value.length % 2 !== 0) {
+                throw new Error(`Tried to assign ${value}, which is contains a half-byte. Use full bytes only.`);
+            }
         }
-        // Convert value into a buffer and do bounds checking
         const valueBuf = ethUtil.toBuffer(value);
         if (valueBuf.byteLength > this._width) {
             throw new Error(
@@ -49,20 +71,6 @@ export class StaticBytes extends PayloadDataType {
                     valueBuf.byteLength
                 } bytes), which exceeds max bytes that can be stored in a ${this.getSignature()}`,
             );
-        } else if (value.length % 2 !== 0) {
-            throw new Error(`Tried to assign ${value}, which is contains a half-byte. Use full bytes only.`);
         }
-
-        // Store value as hex
-        const evmWordWidth = 32;
-        const paddedValue = ethUtil.setLengthRight(valueBuf, evmWordWidth);
-        return paddedValue;
-    }
-
-    public decodeValue(calldata: RawCalldata): string {
-        const paddedValueBuf = calldata.popWord();
-        const valueBuf = paddedValueBuf.slice(0, this._width);
-        const value = ethUtil.bufferToHex(valueBuf);
-        return value;
     }
 }
diff --git a/packages/utils/src/abi_encoder/evm_data_types/string.ts b/packages/utils/src/abi_encoder/evm_data_types/string.ts
index 47ad7cb97..15b93e447 100644
--- a/packages/utils/src/abi_encoder/evm_data_types/string.ts
+++ b/packages/utils/src/abi_encoder/evm_data_types/string.ts
@@ -13,7 +13,7 @@ export class String extends PayloadDataType {
     public static matchType(type: string): boolean {
         return type === 'string';
     }
-
+    
     public constructor(dataItem: DataItem, dataTypeFactory: DataTypeFactory) {
         super(dataItem, dataTypeFactory, String._SIZE_KNOWN_AT_COMPILE_TIME);
         if (!String.matchType(dataItem.type)) {
@@ -22,21 +22,30 @@ export class String extends PayloadDataType {
     }
 
     public encodeValue(value: string): Buffer {
-        const wordsForValue = Math.ceil(value.length / Constants.EVM_WORD_WIDTH_IN_BYTES);
-        const paddedDynamicBytesForValue = wordsForValue * Constants.EVM_WORD_WIDTH_IN_BYTES;
-        const valueBuf = ethUtil.setLengthRight(new Buffer(value), paddedDynamicBytesForValue);
-        const lengthBuf = ethUtil.setLengthLeft(ethUtil.toBuffer(value.length), Constants.EVM_WORD_WIDTH_IN_BYTES);
-        const encodedValueBuf = Buffer.concat([lengthBuf, valueBuf]);
+        // Encoded value is of the form: <length><value>, with each field padded to be word-aligned.
+        // 1/3 Construct the length
+        const wordsToStoreValuePadded = Math.ceil(value.length / Constants.EVM_WORD_WIDTH_IN_BYTES);
+        const bytesToStoreValuePadded = wordsToStoreValuePadded * Constants.EVM_WORD_WIDTH_IN_BYTES;
+        const lengthBuf = ethUtil.toBuffer(value.length);
+        const lengthBufPadded = ethUtil.setLengthLeft(lengthBuf, Constants.EVM_WORD_WIDTH_IN_BYTES);
+        // 2/3 Construct the value
+        const valueBuf = new Buffer(value);
+        const valueBufPadded = ethUtil.setLengthRight(valueBuf, bytesToStoreValuePadded);
+        // 3/3 Combine length and value
+        const encodedValueBuf = Buffer.concat([lengthBufPadded, valueBufPadded]);
         return encodedValueBuf;
     }
 
     public decodeValue(calldata: RawCalldata): string {
-        const lengthBuf = calldata.popWord();
-        const lengthHex = ethUtil.bufferToHex(lengthBuf);
-        const length = parseInt(lengthHex, Constants.HEX_BASE);
-        const wordsForValue = Math.ceil(length / Constants.EVM_WORD_WIDTH_IN_BYTES);
-        const paddedValueBuf = calldata.popWords(wordsForValue);
-        const valueBuf = paddedValueBuf.slice(0, length);
+        // Encoded value is of the form: <length><value>, with each field padded to be word-aligned.
+        // 1/2 Decode length
+        const lengthBufPadded = calldata.popWord();
+        const lengthHexPadded = ethUtil.bufferToHex(lengthBufPadded);
+        const length = parseInt(lengthHexPadded, Constants.HEX_BASE);
+        // 2/2 Decode value
+        const wordsToStoreValuePadded = Math.ceil(length / Constants.EVM_WORD_WIDTH_IN_BYTES);
+        const valueBufPadded = calldata.popWords(wordsToStoreValuePadded);
+        const valueBuf = valueBufPadded.slice(0, length);
         const value = valueBuf.toString('ascii');
         return value;
     }
diff --git a/packages/utils/src/abi_encoder/evm_data_types/tuple.ts b/packages/utils/src/abi_encoder/evm_data_types/tuple.ts
index 4a90e375a..89dd6604d 100644
--- a/packages/utils/src/abi_encoder/evm_data_types/tuple.ts
+++ b/packages/utils/src/abi_encoder/evm_data_types/tuple.ts
@@ -3,8 +3,8 @@ import { DataItem } from 'ethereum-types';
 import { DataTypeFactory, MemberDataType } from '../abstract_data_types';
 
 export class Tuple extends MemberDataType {
-    private readonly _tupleSignature: string;
-
+    private readonly _signature: string;
+    
     public static matchType(type: string): boolean {
         return type === 'tuple';
     }
@@ -14,10 +14,10 @@ export class Tuple extends MemberDataType {
         if (!Tuple.matchType(dataItem.type)) {
             throw new Error(`Tried to instantiate Tuple with bad input: ${dataItem}`);
         }
-        this._tupleSignature = this._computeSignatureOfMembers();
+        this._signature = this._computeSignatureOfMembers();
     }
 
     public getSignature(): string {
-        return this._tupleSignature;
+        return this._signature;
     }
 }
diff --git a/packages/utils/src/abi_encoder/utils/queue.ts b/packages/utils/src/abi_encoder/utils/queue.ts
index 53afb7e11..506a0b56e 100644
--- a/packages/utils/src/abi_encoder/utils/queue.ts
+++ b/packages/utils/src/abi_encoder/utils/queue.ts
@@ -32,7 +32,7 @@ export class Queue<T> {
     public getStore(): T[] {
         return this._store;
     }
-
+    
     public peekFront(): T | undefined {
         return this._store.length >= 0 ? this._store[0] : undefined;
     }