allow for deleting array position in agency kv-store

arangod/Agency/Node.cpp

@@ -464,24 +464,55 @@ bool Node::handle<PUSH>(VPackSlice const& slice) {
   return true;
 }
 
-/// Remove element from any place in array by value array
+/// Remove element from any place in array by value or position
-template <>
+template <> bool Node::handle<ERASE>(VPackSlice const& slice) {
-bool Node::handle<ERASE>(VPackSlice const& slice) {
+  bool haveVal = slice.hasKey("val");
-  if (!slice.hasKey("val")) {
+  bool havePos = slice.hasKey("pos");
+
+  if (!haveVal && !havePos) {
     LOG_TOPIC(WARN, Logger::AGENCY)
-        << "Operator erase without value to be erased: " << slice.toJson();
+      << "Operator erase without value or position to be erased is illegal: "
+      << slice.toJson();
     return false;
+  } else if (haveVal && havePos) {
+    LOG_TOPIC(WARN, Logger::AGENCY)
+      << "Operator erase with value and position to be erased is illegal: "
+      << slice.toJson();
+    return false;
+  } else if (havePos &&
+             (!slice.get("pos").isUInt() && !slice.get("pos").isSmallInt())) {
+    LOG_TOPIC(WARN, Logger::AGENCY)
+      << "Operator erase with non-positive integer position is illegal: "
+      << slice.toJson();
   }
+  
   Builder tmp;
   { VPackArrayBuilder t(&tmp);
+    
     if (this->slice().isArray()) {
-      for (auto const& old : VPackArrayIterator(this->slice())) {
+      if (haveVal) {
-        if (old != slice.get("val")) {
+        for (auto const& old : VPackArrayIterator(this->slice())) {
-          tmp.add(old);
+          if (old != slice.get("val")) {
+            tmp.add(old);
+          }
+        }
+      } else {
+        size_t pos = slice.get("pos").getNumber<size_t>();
+        if (pos >= this->slice().length()) {
+          return false;
+        }
+        size_t n = 0;
+        for (const auto& old : VPackArrayIterator(this->slice())) {
+          if (n != pos) {
+            tmp.add(old);
+          }
+          ++n;
         }
       }
     }
+    
   }
+  
   *this = tmp.slice();
   return true;
 }

js/client/tests/agency/agency-test.js

@@ -605,7 +605,9 @@ function agencyTestSuite () {
 ////////////////////////////////////////////////////////////////////////////////
 
     testOpErase : function () {
+      
       writeAndCheck([[{"/version":{"op":"delete"}}]]);
+      
       writeAndCheck([[{"/a":[0,1,2,3,4,5,6,7,8,9]}]]); // none before
       assertEqual(readAndCheck([["/a"]]), [{a:[0,1,2,3,4,5,6,7,8,9]}]);
       writeAndCheck([[{"a":{"op":"erase","val":3}}]]);
@@ -629,6 +631,28 @@ function agencyTestSuite () {
       writeAndCheck([[{"a":{"op":"erase","val":6}}],
                      [{"a":{"op":"erase","val":8}}]]);
       assertEqual(readAndCheck([["/a"]]), [{a:[]}]);
+      
+      writeAndCheck([[{"/a":[0,1,2,3,4,5,6,7,8,9]}]]); // none before
+      assertEqual(readAndCheck([["/a"]]), [{a:[0,1,2,3,4,5,6,7,8,9]}]);
+      writeAndCheck([[{"a":{"op":"erase","pos":3}}]]);
+      assertEqual(readAndCheck([["/a"]]), [{a:[0,1,2,4,5,6,7,8,9]}]);
+      writeAndCheck([[{"a":{"op":"erase","pos":0}}]]);
+      assertEqual(readAndCheck([["/a"]]), [{a:[1,2,4,5,6,7,8,9]}]);
+      writeAndCheck([[{"a":{"op":"erase","pos":0}}]]);
+      assertEqual(readAndCheck([["/a"]]), [{a:[2,4,5,6,7,8,9]}]);
+      writeAndCheck([[{"a":{"op":"erase","pos":2}}]]);
+      assertEqual(readAndCheck([["/a"]]), [{a:[2,4,6,7,8,9]}]);
+      writeAndCheck([[{"a":{"op":"erase","pos":4}}]]);
+      assertEqual(readAndCheck([["/a"]]), [{a:[2,4,6,7,9]}]);
+      writeAndCheck([[{"a":{"op":"erase","pos":2}}]]);
+      assertEqual(readAndCheck([["/a"]]), [{a:[2,4,7,9]}]);
+      writeAndCheck([[{"a":{"op":"erase","pos":2}}]]);
+      assertEqual(readAndCheck([["/a"]]), [{a:[2,4,9]}]);
+      writeAndCheck([[{"a":{"op":"erase","pos":0}}]]);
+      assertEqual(readAndCheck([["/a"]]), [{a:[4,9]}]);
+      writeAndCheck([[{"a":{"op":"erase","pos":1}}],
+                     [{"a":{"op":"erase","pos":0}}]]);
+      assertEqual(readAndCheck([["/a"]]), [{a:[]}]);      
     },
 
 ////////////////////////////////////////////////////////////////////////////////