Merge #8421: httpserver: drop boost (#8023 dependency)

7e87033 httpserver: replace boost threads with std (Cory Fields)
d3773ca httpserver: explicitly detach worker threads (Cory Fields)
755aa05 httpserver: use a future rather than relying on boost's try_join_for (Cory Fields)

Author: laanwj

src/httpserver.cpp

@@ -19,6 +19,7 @@
 #include <sys/types.h>
 #include <sys/stat.h>
 #include <signal.h>
+#include <future>
 
 #include <event2/event.h>
 #include <event2/http.h>
@@ -34,9 +35,6 @@
 #endif
 #endif
 
-#include <boost/algorithm/string/case_conv.hpp> // for to_lower()
-#include <boost/foreach.hpp>
-
 /** Maximum size of http request (request line + headers) */
 static const size_t MAX_HEADERS_SIZE = 8192;
 
@@ -68,8 +66,8 @@ class WorkQueue
 {
 private:
     /** Mutex protects entire object */
-    CWaitableCriticalSection cs;
-    CConditionVariable cond;
+    std::mutex cs;
+    std::condition_variable cond;
     std::deque<std::unique_ptr<WorkItem>> queue;
     bool running;
     size_t maxDepth;
@@ -82,12 +80,12 @@ class WorkQueue
         WorkQueue &wq;
         ThreadCounter(WorkQueue &w): wq(w)
         {
-            boost::lock_guard<boost::mutex> lock(wq.cs);
+            std::lock_guard<std::mutex> lock(wq.cs);
             wq.numThreads += 1;
         }
         ~ThreadCounter()
         {
-            boost::lock_guard<boost::mutex> lock(wq.cs);
+            std::lock_guard<std::mutex> lock(wq.cs);
             wq.numThreads -= 1;
             wq.cond.notify_all();
         }
@@ -108,7 +106,7 @@ class WorkQueue
     /** Enqueue a work item */
     bool Enqueue(WorkItem* item)
     {
-        boost::unique_lock<boost::mutex> lock(cs);
+        std::unique_lock<std::mutex> lock(cs);
         if (queue.size() >= maxDepth) {
             return false;
         }
@@ -123,7 +121,7 @@ class WorkQueue
         while (running) {
             std::unique_ptr<WorkItem> i;
             {
-                boost::unique_lock<boost::mutex> lock(cs);
+                std::unique_lock<std::mutex> lock(cs);
                 while (running && queue.empty())
                     cond.wait(lock);
                 if (!running)
@@ -137,22 +135,22 @@ class WorkQueue
     /** Interrupt and exit loops */
     void Interrupt()
     {
-        boost::unique_lock<boost::mutex> lock(cs);
+        std::unique_lock<std::mutex> lock(cs);
         running = false;
         cond.notify_all();
     }
     /** Wait for worker threads to exit */
     void WaitExit()
     {
-        boost::unique_lock<boost::mutex> lock(cs);
+        std::unique_lock<std::mutex> lock(cs);
         while (numThreads > 0)
             cond.wait(lock);
     }
 
     /** Return current depth of queue */
     size_t Depth()
     {
-        boost::unique_lock<boost::mutex> lock(cs);
+        std::unique_lock<std::mutex> lock(cs);
         return queue.size();
     }
 };
@@ -189,7 +187,7 @@ static bool ClientAllowed(const CNetAddr& netaddr)
 {
     if (!netaddr.IsValid())
         return false;
-    BOOST_FOREACH (const CSubNet& subnet, rpc_allow_subnets)
+    for(const CSubNet& subnet : rpc_allow_subnets)
         if (subnet.Match(netaddr))
             return true;
     return false;
@@ -203,7 +201,7 @@ static bool InitHTTPAllowList()
     rpc_allow_subnets.push_back(CSubNet("::1"));         // always allow IPv6 localhost
     if (mapMultiArgs.count("-rpcallowip")) {
         const std::vector<std::string>& vAllow = mapMultiArgs["-rpcallowip"];
-        BOOST_FOREACH (std::string strAllow, vAllow) {
+        for (std::string strAllow : vAllow) {
             CSubNet subnet(strAllow);
             if (!subnet.IsValid()) {
                 uiInterface.ThreadSafeMessageBox(
@@ -215,7 +213,7 @@ static bool InitHTTPAllowList()
         }
     }
     std::string strAllowed;
-    BOOST_FOREACH (const CSubNet& subnet, rpc_allow_subnets)
+    for (const CSubNet& subnet : rpc_allow_subnets)
         strAllowed += subnet.ToString() + " ";
     LogPrint("http", "Allowing HTTP connections from: %s\n", strAllowed);
     return true;
@@ -302,13 +300,14 @@ static void http_reject_request_cb(struct evhttp_request* req, void*)
 }
 
 /** Event dispatcher thread */
-static void ThreadHTTP(struct event_base* base, struct evhttp* http)
+static bool ThreadHTTP(struct event_base* base, struct evhttp* http)
 {
     RenameThread("bitcoin-http");
     LogPrint("http", "Entering http event loop\n");
     event_base_dispatch(base);
     // Event loop will be interrupted by InterruptHTTPServer()
     LogPrint("http", "Exited http event loop\n");
+    return event_base_got_break(base) == 0;
 }
 
 /** Bind HTTP server to specified addresses */
@@ -437,17 +436,22 @@ bool InitHTTPServer()
     return true;
 }
 
-boost::thread threadHTTP;
+std::thread threadHTTP;
+std::future<bool> threadResult;
 
 bool StartHTTPServer()
 {
     LogPrint("http", "Starting HTTP server\n");
     int rpcThreads = std::max((long)GetArg("-rpcthreads", DEFAULT_HTTP_THREADS), 1L);
     LogPrintf("HTTP: starting %d worker threads\n", rpcThreads);
-    threadHTTP = boost::thread(boost::bind(&ThreadHTTP, eventBase, eventHTTP));
+    std::packaged_task<bool(event_base*, evhttp*)> task(ThreadHTTP);
+    threadResult = task.get_future();
+    threadHTTP = std::thread(std::move(task), eventBase, eventHTTP);
 
-    for (int i = 0; i < rpcThreads; i++)
-        boost::thread(boost::bind(&HTTPWorkQueueRun, workQueue));
+    for (int i = 0; i < rpcThreads; i++) {
+        std::thread rpc_worker(HTTPWorkQueueRun, workQueue);
+        rpc_worker.detach();
+    }
     return true;
 }
 
@@ -456,7 +460,7 @@ void InterruptHTTPServer()
     LogPrint("http", "Interrupting HTTP server\n");
     if (eventHTTP) {
         // Unlisten sockets
-        BOOST_FOREACH (evhttp_bound_socket *socket, boundSockets) {
+        for (evhttp_bound_socket *socket : boundSockets) {
             evhttp_del_accept_socket(eventHTTP, socket);
         }
         // Reject requests on current connections
@@ -482,15 +486,11 @@ void StopHTTPServer()
         // master that appears to be solved, so in the future that solution
         // could be used again (if desirable).
         // (see discussion in https://github.com/bitcoin/bitcoin/pull/6990)
-#if BOOST_VERSION >= 105000
-        if (!threadHTTP.try_join_for(boost::chrono::milliseconds(2000))) {
-#else
-        if (!threadHTTP.timed_join(boost::posix_time::milliseconds(2000))) {
-#endif
+        if (threadResult.valid() && threadResult.wait_for(std::chrono::milliseconds(2000)) == std::future_status::timeout) {
             LogPrintf("HTTP event loop did not exit within allotted time, sending loopbreak\n");
             event_base_loopbreak(eventBase);
-            threadHTTP.join();
         }
+        threadHTTP.join();
     }
     if (eventHTTP) {
         evhttp_free(eventHTTP);
@@ -517,7 +517,7 @@ static void httpevent_callback_fn(evutil_socket_t, short, void* data)
         delete self;
 }
 
-HTTPEvent::HTTPEvent(struct event_base* base, bool deleteWhenTriggered, const boost::function<void(void)>& handler):
+HTTPEvent::HTTPEvent(struct event_base* base, bool deleteWhenTriggered, const std::function<void(void)>& handler):
     deleteWhenTriggered(deleteWhenTriggered), handler(handler)
 {
     ev = event_new(base, -1, 0, httpevent_callback_fn, this);
@@ -599,7 +599,7 @@ void HTTPRequest::WriteReply(int nStatus, const std::string& strReply)
     assert(evb);
     evbuffer_add(evb, strReply.data(), strReply.size());
     HTTPEvent* ev = new HTTPEvent(eventBase, true,
-        boost::bind(evhttp_send_reply, req, nStatus, (const char*)NULL, (struct evbuffer *)NULL));
+        std::bind(evhttp_send_reply, req, nStatus, (const char*)NULL, (struct evbuffer *)NULL));
     ev->trigger(0);
     replySent = true;
     req = 0; // transferred back to main thread

src/httpserver.h

@@ -7,9 +7,7 @@
 
 #include <string>
 #include <stdint.h>
-#include <boost/thread.hpp>
-#include <boost/scoped_ptr.hpp>
-#include <boost/function.hpp>
+#include <functional>
 
 static const int DEFAULT_HTTP_THREADS=4;
 static const int DEFAULT_HTTP_WORKQUEUE=16;
@@ -35,7 +33,7 @@ void InterruptHTTPServer();
 void StopHTTPServer();
 
 /** Handler for requests to a certain HTTP path */
-typedef boost::function<void(HTTPRequest* req, const std::string &)> HTTPRequestHandler;
+typedef std::function<void(HTTPRequest* req, const std::string &)> HTTPRequestHandler;
 /** Register handler for prefix.
  * If multiple handlers match a prefix, the first-registered one will
  * be invoked.
@@ -132,7 +130,7 @@ class HTTPEvent
      * deleteWhenTriggered deletes this event object after the event is triggered (and the handler called)
      * handler is the handler to call when the event is triggered.
      */
-    HTTPEvent(struct event_base* base, bool deleteWhenTriggered, const boost::function<void(void)>& handler);
+    HTTPEvent(struct event_base* base, bool deleteWhenTriggered, const std::function<void(void)>& handler);
     ~HTTPEvent();
 
     /** Trigger the event. If tv is 0, trigger it immediately. Otherwise trigger it after
@@ -141,7 +139,7 @@ class HTTPEvent
     void trigger(struct timeval* tv);
 
     bool deleteWhenTriggered;
-    boost::function<void(void)> handler;
+    std::function<void(void)> handler;
 private:
     struct event* ev;
 };