Merge bitcoin#7966: http: Do a pending c++11 simplification handling work items

f0188f9 http: use std::move to move HTTPRequest into HTTPWorkItem (Wladimir J. van der Laan)
37b2137 http: Change boost::scoped_ptr to std::unique_ptr in HTTPRequest (Wladimir J. van der Laan)
f97b410 http: Add log message when work queue is full (Wladimir J. van der Laan)
091d6e0 http: Do a pending c++11 simplification (Wladimir J. van der Laan)

Author: laanwj

src/httpserver.cpp

@@ -36,7 +36,6 @@
 
 #include <boost/algorithm/string/case_conv.hpp> // for to_lower()
 #include <boost/foreach.hpp>
-#include <boost/scoped_ptr.hpp>
 
 /** Maximum size of http request (request line + headers) */
 static const size_t MAX_HEADERS_SIZE = 8192;
@@ -45,16 +44,16 @@ static const size_t MAX_HEADERS_SIZE = 8192;
 class HTTPWorkItem : public HTTPClosure
 {
 public:
-    HTTPWorkItem(HTTPRequest* req, const std::string &path, const HTTPRequestHandler& func):
-        req(req), path(path), func(func)
+    HTTPWorkItem(std::unique_ptr<HTTPRequest> req, const std::string &path, const HTTPRequestHandler& func):
+        req(std::move(req)), path(path), func(func)
     {
     }
     void operator()()
     {
         func(req.get(), path);
     }
 
-    boost::scoped_ptr<HTTPRequest> req;
+    std::unique_ptr<HTTPRequest> req;
 
 private:
     std::string path;
@@ -71,8 +70,7 @@ class WorkQueue
     /** Mutex protects entire object */
     CWaitableCriticalSection cs;
     CConditionVariable cond;
-    /* XXX in C++11 we can use std::unique_ptr here and avoid manual cleanup */
-    std::deque<WorkItem*> queue;
+    std::deque<std::unique_ptr<WorkItem>> queue;
     bool running;
     size_t maxDepth;
     int numThreads;
@@ -101,15 +99,11 @@ class WorkQueue
                                  numThreads(0)
     {
     }
-    /*( Precondition: worker threads have all stopped
+    /** Precondition: worker threads have all stopped
      * (call WaitExit)
      */
     ~WorkQueue()
     {
-        while (!queue.empty()) {
-            delete queue.front();
-            queue.pop_front();
-        }
     }
     /** Enqueue a work item */
     bool Enqueue(WorkItem* item)
@@ -118,7 +112,7 @@ class WorkQueue
         if (queue.size() >= maxDepth) {
             return false;
         }
-        queue.push_back(item);
+        queue.emplace_back(std::unique_ptr<WorkItem>(item));
         cond.notify_one();
         return true;
     }
@@ -127,18 +121,17 @@ class WorkQueue
     {
         ThreadCounter count(*this);
         while (true) {
-            WorkItem* i = 0;
+            std::unique_ptr<WorkItem> i;
             {
                 boost::unique_lock<boost::mutex> lock(cs);
                 while (running && queue.empty())
                     cond.wait(lock);
                 if (!running)
                     break;
-                i = queue.front();
+                i = std::move(queue.front());
                 queue.pop_front();
             }
             (*i)();
-            delete i;
         }
     }
     /** Interrupt and exit loops */
@@ -294,12 +287,14 @@ static void http_request_cb(struct evhttp_request* req, void* arg)
 
     // Dispatch to worker thread
     if (i != iend) {
-        std::unique_ptr<HTTPWorkItem> item(new HTTPWorkItem(hreq.release(), path, i->handler));
+        std::unique_ptr<HTTPWorkItem> item(new HTTPWorkItem(std::move(hreq), path, i->handler));
         assert(workQueue);
         if (workQueue->Enqueue(item.get()))
             item.release(); /* if true, queue took ownership */
-        else
+        else {
+            LogPrintf("WARNING: request rejected because http work queue depth exceeded, it can be increased with the -rpcworkqueue= setting\n");
             item->req->WriteReply(HTTP_INTERNAL, "Work queue depth exceeded");
+        }
     } else {
         hreq->WriteReply(HTTP_NOTFOUND);
     }