From 091d6e04998d2c88dd7f42ad2d90929f428764c2 Mon Sep 17 00:00:00 2001
From: "Wladimir J. van der Laan" <laanwj@gmail.com>
Date: Thu, 28 Apr 2016 19:03:05 +0200
Subject: [PATCH 1/4] http: Do a pending c++11 simplification

Use std::unique_ptr for handling work items.

This makes the code more RAII and, as mentioned in the comment, is what
I planned when I wrote the code in the first place.
---
 src/httpserver.cpp | 16 +++++-----------
 1 file changed, 5 insertions(+), 11 deletions(-)

diff --git a/src/httpserver.cpp b/src/httpserver.cpp
index a98eff7c1..8297b6f75 100644
--- a/src/httpserver.cpp
+++ b/src/httpserver.cpp
@@ -71,8 +71,7 @@ private:
     /** 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 +100,11 @@ public:
                                  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 +113,7 @@ public:
         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 +122,17 @@ public:
     {
         ThreadCounter count(*this);
         while (running) {
-            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 */

From f97b410fdd57743f9a26ea49086534000eb9626a Mon Sep 17 00:00:00 2001
From: "Wladimir J. van der Laan" <laanwj@gmail.com>
Date: Wed, 4 May 2016 15:37:26 +0200
Subject: [PATCH 2/4] http: Add log message when work queue is full

More useful error reporting.
---
 src/httpserver.cpp | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/src/httpserver.cpp b/src/httpserver.cpp
index 8297b6f75..67a9e1e92 100644
--- a/src/httpserver.cpp
+++ b/src/httpserver.cpp
@@ -286,8 +286,10 @@ static void http_request_cb(struct evhttp_request* req, void* arg)
         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);
     }

From 37b21372a0a3e5d876a87f03c8cbef2e02d8dc92 Mon Sep 17 00:00:00 2001
From: "Wladimir J. van der Laan" <laanwj@gmail.com>
Date: Wed, 4 May 2016 15:55:23 +0200
Subject: [PATCH 3/4] http: Change boost::scoped_ptr to std::unique_ptr in
 HTTPRequest

No need for boost here.
---
 src/httpserver.cpp | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/httpserver.cpp b/src/httpserver.cpp
index 67a9e1e92..c193d2af1 100644
--- a/src/httpserver.cpp
+++ b/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;
@@ -54,7 +53,7 @@ public:
         func(req.get(), path);
     }
 
-    boost::scoped_ptr<HTTPRequest> req;
+    std::unique_ptr<HTTPRequest> req;
 
 private:
     std::string path;

From f0188f9178a22fd493ed228c008d4cc25ac2952d Mon Sep 17 00:00:00 2001
From: "Wladimir J. van der Laan" <laanwj@gmail.com>
Date: Wed, 4 May 2016 16:05:17 +0200
Subject: [PATCH 4/4] http: use std::move to move HTTPRequest into HTTPWorkItem

Thanks to Cory Fields for the idea.
---
 src/httpserver.cpp | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/src/httpserver.cpp b/src/httpserver.cpp
index c193d2af1..812940eaf 100644
--- a/src/httpserver.cpp
+++ b/src/httpserver.cpp
@@ -44,8 +44,8 @@ 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()()
@@ -281,7 +281,7 @@ 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 */