Merge #9387: [Refactor] RAII of libevent stuff using unique ptrs with deleters

05a55a6 Added EVENT_CFLAGS to test makefile to explicitly include libevent headers. (Karl-Johan Alm)
280a559 Added some simple tests for the RAII-style events. (Karl-Johan Alm)
7f7f102 Switched bitcoin-cli.cpp to use RAII unique pointers with deleters. (Karl-Johan Alm)
e5534d2 Added std::unique_ptr<> wrappers with deleters for libevent modules. (Karl-Johan Alm)

src/Makefile.am

@@ -135,6 +135,7 @@ BITCOIN_CORE_H = \
   support/allocators/secure.h \
   support/allocators/zeroafterfree.h \
   support/cleanse.h \
+  support/events.h \
   support/lockedpool.h \
   sync.h \
   threadsafety.h \

src/Makefile.test.include

@@ -88,6 +88,7 @@ BITCOIN_TESTS =\
   test/policyestimator_tests.cpp \
   test/pow_tests.cpp \
   test/prevector_tests.cpp \
+  test/raii_event_tests.cpp \
   test/reverselock_tests.cpp \
   test/rpc_tests.cpp \
   test/sanity_tests.cpp \
@@ -123,9 +124,9 @@ BITCOIN_TESTS += \
 endif
 
 test_test_bitcoin_SOURCES = $(BITCOIN_TESTS) $(JSON_TEST_FILES) $(RAW_TEST_FILES)
-test_test_bitcoin_CPPFLAGS = $(AM_CPPFLAGS) $(BITCOIN_INCLUDES) -I$(builddir)/test/ $(TESTDEFS)
+test_test_bitcoin_CPPFLAGS = $(AM_CPPFLAGS) $(BITCOIN_INCLUDES) -I$(builddir)/test/ $(TESTDEFS) $(EVENT_CFLAGS)
 test_test_bitcoin_LDADD = $(LIBBITCOIN_SERVER) $(LIBBITCOIN_CLI) $(LIBBITCOIN_COMMON) $(LIBBITCOIN_UTIL) $(LIBBITCOIN_CONSENSUS) $(LIBBITCOIN_CRYPTO) $(LIBUNIVALUE) $(LIBLEVELDB) $(LIBMEMENV) \
-  $(BOOST_LIBS) $(BOOST_UNIT_TEST_FRAMEWORK_LIB) $(LIBSECP256K1)
+  $(BOOST_LIBS) $(BOOST_UNIT_TEST_FRAMEWORK_LIB) $(LIBSECP256K1) $(EVENT_LIBS)
 test_test_bitcoin_CXXFLAGS = $(AM_CXXFLAGS) $(PIE_FLAGS)
 if ENABLE_WALLET
 test_test_bitcoin_LDADD += $(LIBBITCOIN_WALLET)

src/bitcoin-cli.cpp

@@ -17,10 +17,9 @@
 #include <boost/filesystem/operations.hpp>
 #include <stdio.h>
 
-#include <event2/event.h>
-#include <event2/http.h>
 #include <event2/buffer.h>
 #include <event2/keyvalq_struct.h>
+#include "support/events.h"
 
 #include <univalue.h>
 
@@ -190,23 +189,19 @@ UniValue CallRPC(const std::string& strMethod, const UniValue& params)
     std::string host = GetArg("-rpcconnect", DEFAULT_RPCCONNECT);
     int port = GetArg("-rpcport", BaseParams().RPCPort());
 
-    // Create event base
+    // Obtain event base
-    struct event_base *base = event_base_new(); // TODO RAII
+    raii_event_base base = obtain_event_base();
-    if (!base)
-        throw std::runtime_error("cannot create event_base");
 
     // Synchronously look up hostname
-    struct evhttp_connection *evcon = evhttp_connection_base_new(base, NULL, host.c_str(), port); // TODO RAII
+    raii_evhttp_connection evcon = obtain_evhttp_connection_base(base.get(), host, port);
-    if (evcon == NULL)
+    evhttp_connection_set_timeout(evcon.get(), GetArg("-rpcclienttimeout", DEFAULT_HTTP_CLIENT_TIMEOUT));
-        throw std::runtime_error("create connection failed");
-    evhttp_connection_set_timeout(evcon, GetArg("-rpcclienttimeout", DEFAULT_HTTP_CLIENT_TIMEOUT));
 
     HTTPReply response;
-    struct evhttp_request *req = evhttp_request_new(http_request_done, (void*)&response); // TODO RAII
+    raii_evhttp_request req = obtain_evhttp_request(http_request_done, (void*)&response);
     if (req == NULL)
         throw std::runtime_error("create http request failed");
 #if LIBEVENT_VERSION_NUMBER >= 0x02010300
-    evhttp_request_set_error_cb(req, http_error_cb);
+    evhttp_request_set_error_cb(req.get(), http_error_cb);
 #endif
 
     // Get credentials
@@ -223,7 +218,7 @@ UniValue CallRPC(const std::string& strMethod, const UniValue& params)
         strRPCUserColonPass = GetArg("-rpcuser", "") + ":" + GetArg("-rpcpassword", "");
     }
 
-    struct evkeyvalq *output_headers = evhttp_request_get_output_headers(req);
+    struct evkeyvalq* output_headers = evhttp_request_get_output_headers(req.get());
     assert(output_headers);
     evhttp_add_header(output_headers, "Host", host.c_str());
     evhttp_add_header(output_headers, "Connection", "close");
@@ -231,20 +226,17 @@ UniValue CallRPC(const std::string& strMethod, const UniValue& params)
 
     // Attach request data
     std::string strRequest = JSONRPCRequestObj(strMethod, params, 1).write() + "\n";
-    struct evbuffer * output_buffer = evhttp_request_get_output_buffer(req);
+    struct evbuffer* output_buffer = evhttp_request_get_output_buffer(req.get());
     assert(output_buffer);
     evbuffer_add(output_buffer, strRequest.data(), strRequest.size());
 
-    int r = evhttp_make_request(evcon, req, EVHTTP_REQ_POST, "/");
+    int r = evhttp_make_request(evcon.get(), req.get(), EVHTTP_REQ_POST, "/");
+    req.release(); // ownership moved to evcon in above call
     if (r != 0) {
-        evhttp_connection_free(evcon);
-        event_base_free(base);
         throw CConnectionFailed("send http request failed");
     }
 
-    event_base_dispatch(base);
+    event_base_dispatch(base.get());
-    evhttp_connection_free(evcon);
-    event_base_free(base);
 
     if (response.status == 0)
         throw CConnectionFailed(strprintf("couldn't connect to server: %s (code %d)\n(make sure server is running and you are connecting to the correct RPC port)", http_errorstring(response.error), response.error));

src/support/events.h

@@ -0,0 +1,56 @@
+// Copyright (c) 2016 The Bitcoin Core developers
+// Distributed under the MIT software license, see the accompanying
+// file COPYING or http://www.opensource.org/licenses/mit-license.php.
+
+#ifndef BITCOIN_SUPPORT_EVENTS_H
+#define BITCOIN_SUPPORT_EVENTS_H
+
+#include <ios>
+#include <memory>
+
+#include <event2/event.h>
+#include <event2/http.h>
+
+#define MAKE_RAII(type) \
+/* deleter */\
+struct type##_deleter {\
+    void operator()(struct type* ob) {\
+        type##_free(ob);\
+    }\
+};\
+/* unique ptr typedef */\
+typedef std::unique_ptr<struct type, type##_deleter> raii_##type
+
+MAKE_RAII(event_base);
+MAKE_RAII(event);
+MAKE_RAII(evhttp);
+MAKE_RAII(evhttp_request);
+MAKE_RAII(evhttp_connection);
+
+raii_event_base obtain_event_base() {
+    auto result = raii_event_base(event_base_new());
+    if (!result.get())
+        throw std::runtime_error("cannot create event_base");
+    return result;
+}
+
+raii_event obtain_event(struct event_base* base, evutil_socket_t s, short events, event_callback_fn cb, void* arg) {
+    return raii_event(event_new(base, s, events, cb, arg));
+}
+
+raii_evhttp obtain_evhttp(struct event_base* base) {
+    return raii_evhttp(evhttp_new(base));
+}
+
+raii_evhttp_request obtain_evhttp_request(void(*cb)(struct evhttp_request *, void *), void *arg) {
+    return raii_evhttp_request(evhttp_request_new(cb, arg));
+}
+
+raii_evhttp_connection obtain_evhttp_connection_base(struct event_base* base, std::string host, uint16_t port) {
+    auto result = raii_evhttp_connection(evhttp_connection_base_new(base, NULL, host.c_str(), port));
+    if (!result.get())
+        throw std::runtime_error("create connection failed");
+    return result;
+}
+
+#endif // BITCOIN_SUPPORT_EVENTS_H

src/test/raii_event_tests.cpp

@@ -0,0 +1,88 @@
+// Copyright (c) 2016 The Bitcoin Core developers
+// Distributed under the MIT software license, see the accompanying
+// file COPYING or http://www.opensource.org/licenses/mit-license.php.
+
+#include <event2/event.h>
+#include <map>
+#include <stdlib.h>
+
+#include "support/events.h"
+
+#include "test/test_bitcoin.h"
+
+#include <vector>
+
+#include <boost/test/unit_test.hpp>
+
+static std::map<void*, short> tags;
+static std::map<void*, uint16_t> orders;
+static uint16_t tagSequence = 0;
+
+static void* tag_malloc(size_t sz) {
+    void* mem = malloc(sz);
+    if (!mem) return mem;
+    tags[mem]++;
+    orders[mem] = tagSequence++;
+    return mem;
+}
+
+static void tag_free(void* mem) {
+    tags[mem]--;
+    orders[mem] = tagSequence++;
+    free(mem);
+}
+
+BOOST_FIXTURE_TEST_SUITE(raii_event_tests, BasicTestingSetup)
+
+BOOST_AUTO_TEST_CASE(raii_event_creation)
+{
+    event_set_mem_functions(tag_malloc, realloc, tag_free);
+    
+    void* base_ptr = NULL;
+    {
+        auto base = obtain_event_base();
+        base_ptr = (void*)base.get();
+        BOOST_CHECK(tags[base_ptr] == 1);
+    }
+    BOOST_CHECK(tags[base_ptr] == 0);
+    
+    void* event_ptr = NULL;
+    {
+        auto base = obtain_event_base();
+        auto event = obtain_event(base.get(), -1, 0, NULL, NULL);
+
+        base_ptr = (void*)base.get();
+        event_ptr = (void*)event.get();
+
+        BOOST_CHECK(tags[base_ptr] == 1);
+        BOOST_CHECK(tags[event_ptr] == 1);
+    }
+    BOOST_CHECK(tags[base_ptr] == 0);
+    BOOST_CHECK(tags[event_ptr] == 0);
+    
+    event_set_mem_functions(malloc, realloc, free);
+}
+
+BOOST_AUTO_TEST_CASE(raii_event_order)
+{
+    event_set_mem_functions(tag_malloc, realloc, tag_free);
+    
+    void* base_ptr = NULL;
+    void* event_ptr = NULL;
+    {
+        auto base = obtain_event_base();
+        auto event = obtain_event(base.get(), -1, 0, NULL, NULL);
+
+        base_ptr = (void*)base.get();
+        event_ptr = (void*)event.get();
+
+        // base should have allocated before event
+        BOOST_CHECK(orders[base_ptr] < orders[event_ptr]);
+    }
+    // base should be freed after event
+    BOOST_CHECK(orders[base_ptr] > orders[event_ptr]);
+
+    event_set_mem_functions(malloc, realloc, free);
+}
+
+BOOST_AUTO_TEST_SUITE_END()