diff options
| -rw-r--r-- | docs/control-structures.rst | 37 | ||||
| -rw-r--r-- | libsolidity/codegen/ExpressionCompiler.cpp | 3 | ||||
| -rw-r--r-- | test/libsolidity/SolidityEndToEndTest.cpp | 27 |
3 files changed, 67 insertions, 0 deletions
diff --git a/docs/control-structures.rst b/docs/control-structures.rst index e03d8d6a..6fa04715 100644 --- a/docs/control-structures.rst +++ b/docs/control-structures.rst @@ -106,6 +106,43 @@ of unused parameters (especially return parameters) can be omitted. } } +.. index:: ! new, contracts;creating + +.. _creating-contracts: + +Creating Contracts via new +========================== + +A contract can create a new contract using the ``new`` keyword. The full +code of the contract to be created has to be known and thus recursive +creation-dependencies are now possible. + +:: + + contract D { + uint x; + function D(uint a) { + x = a; + } + } + contract C { + D d = new D(4); // will be executed as part of C's constructor + + function createD(uint arg) { + D newD = new D(arg); + } + + function createAndEndowD(uint arg, uint amount) { + // Send ether along with the creation + D newD = (new D).value(amount)(arg); + } + } + +As seen in the example, it is possible to forward Ether to the creation, +but it is not possible to limit the amount of gas. If the creation fails +(due to out-of-stack, not enough balance or other problems), an exception +is thrown. + Order of Evaluation of Expressions ================================== diff --git a/libsolidity/codegen/ExpressionCompiler.cpp b/libsolidity/codegen/ExpressionCompiler.cpp index 1d574556..3fbf27ce 100644 --- a/libsolidity/codegen/ExpressionCompiler.cpp +++ b/libsolidity/codegen/ExpressionCompiler.cpp @@ -533,6 +533,9 @@ bool ExpressionCompiler::visit(FunctionCall const& _functionCall) else m_context << u256(0); m_context << Instruction::CREATE; + // Check if zero (out of stack or not enough balance). + m_context << Instruction::DUP1 << Instruction::ISZERO; + m_context.appendConditionalJumpTo(m_context.errorTag()); if (function.valueSet()) m_context << swapInstruction(1) << Instruction::POP; break; diff --git a/test/libsolidity/SolidityEndToEndTest.cpp b/test/libsolidity/SolidityEndToEndTest.cpp index 1b7c5ea4..46756493 100644 --- a/test/libsolidity/SolidityEndToEndTest.cpp +++ b/test/libsolidity/SolidityEndToEndTest.cpp @@ -6839,6 +6839,33 @@ BOOST_AUTO_TEST_CASE(skip_dynamic_types_for_structs) BOOST_CHECK(callContractFunction("g()") == encodeArgs(u256(2), u256(6))); } +BOOST_AUTO_TEST_CASE(failed_create) +{ + char const* sourceCode = R"( + contract D { } + contract C { + uint public x; + function f(uint amount) returns (address) { + x++; + return (new D).value(amount)(); + } + function stack(uint depth) returns (address) { + if (depth < 1024) + return this.stack(depth - 1); + else + return f(0); + } + } + )"; + compileAndRun(sourceCode, 20, "C"); + BOOST_CHECK(callContractFunction("f(uint256)", 20) != encodeArgs(u256(0))); + BOOST_CHECK(callContractFunction("x()") == encodeArgs(u256(1))); + BOOST_CHECK(callContractFunction("f(uint256)", 20) == encodeArgs()); + BOOST_CHECK(callContractFunction("x()") == encodeArgs(u256(1))); + BOOST_CHECK(callContractFunction("stack(uint256)", 1023) == encodeArgs()); + BOOST_CHECK(callContractFunction("x()") == encodeArgs(u256(1))); +} + BOOST_AUTO_TEST_CASE(create_dynamic_array_with_zero_length) { char const* sourceCode = R"( |