New ABI encoder.

libsolidity/codegen/ABIFunctions.h

@@ -0,0 +1,172 @@
+/*
+	This file is part of solidity.
+
+	solidity is free software: you can redistribute it and/or modify
+	it under the terms of the GNU General Public License as published by
+	the Free Software Foundation, either version 3 of the License, or
+	(at your option) any later version.
+
+	solidity is distributed in the hope that it will be useful,
+	but WITHOUT ANY WARRANTY; without even the implied warranty of
+	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+	GNU General Public License for more details.
+
+	You should have received a copy of the GNU General Public License
+	along with solidity.  If not, see <http://www.gnu.org/licenses/>.
+*/
+/**
+ * @author Christian <chris@ethereum.org>
+ * @date 2017
+ * Routines that generate JULIA code related to ABI encoding, decoding and type conversions.
+ */
+
+#pragma once
+
+#include <libsolidity/ast/ASTForward.h>
+
+#include <vector>
+#include <functional>
+#include <map>
+
+namespace dev {
+namespace solidity {
+
+class Type;
+class ArrayType;
+class StructType;
+class FunctionType;
+using TypePointer = std::shared_ptr<Type const>;
+using TypePointers = std::vector<TypePointer>;
+
+///
+/// Class to generate encoding and decoding functions. Also maintains a collection
+/// of "functions to be generated" in order to avoid generating the same function
+/// multiple times.
+///
+/// Make sure to include the result of ``requestedFunctions()`` to a block that
+/// is visible from the code that was generated here.
+class ABIFunctions
+{
+public:
+	~ABIFunctions();
+
+	/// @returns assembly code block to ABI-encode values of @a _givenTypes residing on the stack
+	/// into memory, converting the types to @a _targetTypes on the fly.
+	/// Assumed variables to be present: <$value0> <$value1> ... <$value(n-1)> <$headStart>
+	/// Does not allocate memory (does not change the memory head pointer), but writes
+	/// to memory starting at $headStart and an unrestricted amount after that.
+	/// Assigns the end of encoded memory either to $value0 or (if that is not present)
+	/// to $headStart.
+	std::string tupleEncoder(
+		TypePointers const& _givenTypes,
+		TypePointers const& _targetTypes,
+		bool _encodeAsLibraryTypes = false
+	);
+
+	/// @returns auxiliary functions referenced from the block generated in @a tupleEncoder
+	std::string requestedFunctions();
+
+private:
+	/// @returns the name of the cleanup function for the given type and
+	/// adds its implementation to the requested functions.
+	/// @param _revertOnFailure if true, causes revert on invalid data,
+	/// otherwise an assertion failure.
+	std::string cleanupFunction(Type const& _type, bool _revertOnFailure = false);
+
+	/// @returns the name of the function that converts a value of type @a _from
+	/// to a value of type @a _to. The resulting vale is guaranteed to be in range
+	/// (i.e. "clean"). Asserts on failure.
+	std::string conversionFunction(Type const& _from, Type const& _to);
+
+	std::string cleanupCombinedExternalFunctionIdFunction();
+
+	/// @returns a function that combines the address and selector to a single value
+	/// for use in the ABI.
+	std::string combineExternalFunctionIdFunction();
+
+	/// @returns the name of the ABI encoding function with the given type
+	/// and queues the generation of the function to the requested functions.
+	/// @param _compacted if true, the input value was just loaded from storage
+	/// or memory and thus might be compacted into a single slot (depending on the type).
+	std::string abiEncodingFunction(
+		Type const& _givenType,
+		Type const& _targetType,
+		bool _encodeAsLibraryTypes,
+		bool _compacted
+	);
+	/// Part of @a abiEncodingFunction for array target type and given calldata array.
+	std::string abiEncodingFunctionCalldataArray(
+		Type const& _givenType,
+		Type const& _targetType,
+		bool _encodeAsLibraryTypes
+	);
+	/// Part of @a abiEncodingFunction for array target type and given memory array or
+	/// a given storage array with one item per slot.
+	std::string abiEncodingFunctionSimpleArray(
+		ArrayType const& _givenType,
+		ArrayType const& _targetType,
+		bool _encodeAsLibraryTypes
+	);
+	std::string abiEncodingFunctionMemoryByteArray(
+		ArrayType const& _givenType,
+		ArrayType const& _targetType,
+		bool _encodeAsLibraryTypes
+	);
+	/// Part of @a abiEncodingFunction for array target type and given storage array
+	/// where multiple items are packed into the same storage slot.
+	std::string abiEncodingFunctionCompactStorageArray(
+		ArrayType const& _givenType,
+		ArrayType const& _targetType,
+		bool _encodeAsLibraryTypes
+	);
+
+	// @returns the name of the ABI encoding function with the given type
+	// and queues the generation of the function to the requested functions.
+	// Case for _givenType being a string literal
+	std::string abiEncodingFunctionStringLiteral(
+		Type const& _givenType,
+		Type const& _targetType,
+		bool _encodeAsLibraryTypes
+	);
+
+	std::string abiEncodingFunctionFunctionType(
+		FunctionType const& _from,
+		Type const& _to,
+		bool _encodeAsLibraryTypes,
+		bool _compacted
+	);
+
+	/// @returns a function that copies raw bytes of dynamic length from calldata
+	/// or memory to memory.
+	/// Pads with zeros and might write more than exactly length.
+	std::string copyToMemoryFunction(bool _fromCalldata);
+
+	std::string shiftLeftFunction(size_t _numBits);
+	std::string shiftRightFunction(size_t _numBits, bool _signed);
+	/// @returns the name of a function that rounds its input to the next multiple
+	/// of 32 or the input if it is a multiple of 32.
+	std::string roundUpFunction();
+
+	std::string arrayLengthFunction(ArrayType const& _type);
+	/// @returns the name of a function that converts a storage slot number
+	/// or a memory pointer to the slot number / memory pointer for the data position of an array
+	/// which is stored in that slot / memory area.
+	std::string arrayDataAreaFunction(ArrayType const& _type);
+	/// @returns the name of a function that advances an array data pointer to the next element.
+	/// Only works for memory arrays and storage arrays that store one item per slot.
+	std::string nextArrayElementFunction(ArrayType const& _type);
+
+	/// Helper function that uses @a _creator to create a function and add it to
+	/// @a m_requestedFunctions if it has not been created yet and returns @a _name in both
+	/// cases.
+	std::string createFunction(std::string const& _name, std::function<std::string()> const& _creator);
+
+	/// @returns the size of the static part of the encoding of the given types.
+	size_t headSize(TypePointers const& _targetTypes);
+
+	/// Map from function name to code for a multi-use function.
+	std::map<std::string, std::string> m_requestedFunctions;
+};
+
+}
+}