Merge pull request #6561

7bd57bb Add limitedmap test (Casey Rodarmor)
8b06894 Disallow unlimited limited maps (Casey Rodarmor)
fd2d862 Make limited map actually respect max size (Casey Rodarmor)

Author: laanwj

src/Makefile.test.include

@@ -52,6 +52,7 @@ BITCOIN_TESTS =\
   test/getarg_tests.cpp \
   test/hash_tests.cpp \
   test/key_tests.cpp \
+  test/limitedmap_tests.cpp \
   test/main_tests.cpp \
   test/mempool_tests.cpp \
   test/miner_tests.cpp \

src/limitedmap.h

@@ -27,7 +27,11 @@ class limitedmap
     size_type nMaxSize;
 
 public:
-    limitedmap(size_type nMaxSizeIn = 0) { nMaxSize = nMaxSizeIn; }
+    limitedmap(size_type nMaxSizeIn)
+    {
+        assert(nMaxSizeIn > 0);
+        nMaxSize = nMaxSizeIn;
+    }
     const_iterator begin() const { return map.begin(); }
     const_iterator end() const { return map.end(); }
     size_type size() const { return map.size(); }
@@ -38,13 +42,12 @@ class limitedmap
     {
         std::pair<iterator, bool> ret = map.insert(x);
         if (ret.second) {
-            if (nMaxSize && map.size() == nMaxSize) {
+            if (map.size() > nMaxSize) {
                 map.erase(rmap.begin()->second);
                 rmap.erase(rmap.begin());
             }
             rmap.insert(make_pair(x.second, ret.first));
         }
-        return;
     }
     void erase(const key_type& k)
     {
@@ -81,11 +84,11 @@ class limitedmap
     size_type max_size() const { return nMaxSize; }
     size_type max_size(size_type s)
     {
-        if (s)
-            while (map.size() > s) {
-                map.erase(rmap.begin()->second);
-                rmap.erase(rmap.begin());
-            }
+        assert(s > 0);
+        while (map.size() > s) {
+            map.erase(rmap.begin()->second);
+            rmap.erase(rmap.begin());
+        }
         nMaxSize = s;
         return nMaxSize;
     }

src/test/limitedmap_tests.cpp

@@ -0,0 +1,101 @@
+// Copyright (c) 2012-2015 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 "limitedmap.h"
+
+#include "test/test_bitcoin.h"
+
+#include <boost/test/unit_test.hpp>
+
+BOOST_FIXTURE_TEST_SUITE(limitedmap_tests, BasicTestingSetup)
+
+BOOST_AUTO_TEST_CASE(limitedmap_test)
+{
+    // create a limitedmap capped at 10 items
+    limitedmap<int, int> map(10);
+
+    // check that the max size is 10
+    BOOST_CHECK(map.max_size() == 10);
+
+    // check that it's empty
+    BOOST_CHECK(map.size() == 0);
+
+    // insert (-1, -1)
+    map.insert(std::pair<int, int>(-1, -1));
+
+    // make sure that the size is updated
+    BOOST_CHECK(map.size() == 1);
+
+    // make sure that the new items is in the map
+    BOOST_CHECK(map.count(-1) == 1);
+
+    // insert 10 new items
+    for (int i = 0; i < 10; i++) {
+        map.insert(std::pair<int, int>(i, i + 1));
+    }
+
+    // make sure that the map now contains 10 items...
+    BOOST_CHECK(map.size() == 10);
+
+    // ...and that the first item has been discarded
+    BOOST_CHECK(map.count(-1) == 0);
+
+    // iterate over the map, both with an index and an iterator
+    limitedmap<int, int>::const_iterator it = map.begin();
+    for (int i = 0; i < 10; i++) {
+        // make sure the item is present
+        BOOST_CHECK(map.count(i) == 1);
+
+        // use the iterator to check for the expected key adn value
+        BOOST_CHECK(it->first == i);
+        BOOST_CHECK(it->second == i + 1);
+        
+        // use find to check for the value
+        BOOST_CHECK(map.find(i)->second == i + 1);
+        
+        // update and recheck
+        map.update(it, i + 2);
+        BOOST_CHECK(map.find(i)->second == i + 2);
+
+        it++;
+    }
+
+    // check that we've exhausted the iterator
+    BOOST_CHECK(it == map.end());
+
+    // resize the map to 5 items
+    map.max_size(5);
+
+    // check that the max size and size are now 5
+    BOOST_CHECK(map.max_size() == 5);
+    BOOST_CHECK(map.size() == 5);
+
+    // check that items less than 5 have been discarded
+    // and items greater than 5 are retained
+    for (int i = 0; i < 10; i++) {
+        if (i < 5) {
+            BOOST_CHECK(map.count(i) == 0);
+        } else {
+            BOOST_CHECK(map.count(i) == 1);
+        }
+    }
+
+    // erase some items not in the map
+    for (int i = 100; i < 1000; i += 100) {
+        map.erase(i);
+    }
+
+    // check that the size is unaffected
+    BOOST_CHECK(map.size() == 5);
+
+    // erase the remaining elements
+    for (int i = 5; i < 10; i++) {
+        map.erase(i);
+    }
+
+    // check that the map is now empty
+    BOOST_CHECK(map.empty());
+}
+
+BOOST_AUTO_TEST_SUITE_END()