From 554511b68e69ac88b1535a8f87075e1fe87d4278 Mon Sep 17 00:00:00 2001
From: Alex Beregszaszi <alex@rtfs.hu>
Date: Tue, 22 Jan 2019 11:41:21 +0000
Subject: [PATCH] Introduce solidity_free in libsolc

---
 Changelog.md                 | 1 +
 libsolc/libsolc.cpp          | 4 ++++
 libsolc/libsolc.h            | 5 +++++
 test/libsolidity/LibSolc.cpp | 3 +++
 test/tools/fuzzer_common.cpp | 4 ++++
 5 files changed, 17 insertions(+)

diff --git a/Changelog.md b/Changelog.md
index d3172cb06..86787337e 100644
--- a/Changelog.md
+++ b/Changelog.md
@@ -10,6 +10,7 @@ Language Features:
 
 
 Compiler Features:
+ * C API (``libsolc`` / raw ``soljson.js``): Introduce ``solidity_free`` method which releases all internal buffers to save memory.
 
 
 Bugfixes:
diff --git a/libsolc/libsolc.cpp b/libsolc/libsolc.cpp
index 766e1c0cd..f20b50d46 100644
--- a/libsolc/libsolc.cpp
+++ b/libsolc/libsolc.cpp
@@ -98,4 +98,8 @@ extern char const* solidity_compile(char const* _input, CStyleReadFileCallback _
 	s_outputBuffer = compile(_input, _readCallback);
 	return s_outputBuffer.c_str();
 }
+extern void solidity_free() noexcept
+{
+	s_outputBuffer.clear();
+}
 }
diff --git a/libsolc/libsolc.h b/libsolc/libsolc.h
index baa39fd44..2c55c2342 100644
--- a/libsolc/libsolc.h
+++ b/libsolc/libsolc.h
@@ -55,6 +55,11 @@ char const* solidity_version() SOLC_NOEXCEPT;
 /// The pointer returned must not be freed by the caller.
 char const* solidity_compile(char const* _input, CStyleReadFileCallback _readCallback) SOLC_NOEXCEPT;
 
+/// Frees up any allocated memory.
+///
+/// NOTE: the pointer returned by solidity_compile is invalid after calling this!
+void solidity_free() SOLC_NOEXCEPT;
+
 #ifdef __cplusplus
 }
 #endif
diff --git a/test/libsolidity/LibSolc.cpp b/test/libsolidity/LibSolc.cpp
index ec97f22f0..62ec32f76 100644
--- a/test/libsolidity/LibSolc.cpp
+++ b/test/libsolidity/LibSolc.cpp
@@ -45,6 +45,7 @@ Json::Value compile(string const& _input)
 	string output(solidity_compile(_input.c_str(), nullptr));
 	Json::Value ret;
 	BOOST_REQUIRE(jsonParseStrict(output, ret));
+	solidity_free();
 	return ret;
 }
 
@@ -56,12 +57,14 @@ BOOST_AUTO_TEST_CASE(read_version)
 {
 	string output(solidity_version());
 	BOOST_CHECK(output.find(VersionString) == 0);
+	solidity_free();
 }
 
 BOOST_AUTO_TEST_CASE(read_license)
 {
 	string output(solidity_license());
 	BOOST_CHECK(output.find("GNU GENERAL PUBLIC LICENSE") != string::npos);
+	solidity_free();
 }
 
 BOOST_AUTO_TEST_CASE(standard_compilation)
diff --git a/test/tools/fuzzer_common.cpp b/test/tools/fuzzer_common.cpp
index b661cb54f..0ad86e6ea 100644
--- a/test/tools/fuzzer_common.cpp
+++ b/test/tools/fuzzer_common.cpp
@@ -35,6 +35,10 @@ void FuzzerUtil::runCompiler(string const& _input, bool _quiet)
 	string outputString(solidity_compile(_input.c_str(), nullptr));
 	if (!_quiet)
 		cout << "Output JSON: " << outputString << endl;
+
+	// This should be safe given the above copies the output.
+	solidity_free();
+
 	Json::Value output;
 	if (!jsonParseStrict(outputString, output))
 	{