From 86c21eb733346b6825947d40b44cc732442ba24c Mon Sep 17 00:00:00 2001
From: Jan Christoph Uhde <Jan@UhdeJC.com>
Date: Tue, 29 Nov 2016 14:13:35 +0100
Subject: [PATCH] make use of geo index cursor api

---
 arangod/Indexes/GeoIndex.cpp | 58 ++++++++++++++++++++++++++----------
 arangod/Indexes/GeoIndex.h   | 17 +++++++----
 2 files changed, 53 insertions(+), 22 deletions(-)

diff --git a/arangod/Indexes/GeoIndex.cpp b/arangod/Indexes/GeoIndex.cpp
index 911ab6f952..8e941bf237 100644
--- a/arangod/Indexes/GeoIndex.cpp
+++ b/arangod/Indexes/GeoIndex.cpp
@@ -26,6 +26,7 @@
 #include "Basics/StringRef.h"
 #include "Basics/VelocyPackHelper.h"
 #include "VocBase/transaction.h"
+#include "Indexes/GeoIndex.h"
 
 using namespace arangodb;
 GeoIndexIterator::GeoIndexIterator(LogicalCollection* collection,
@@ -39,28 +40,54 @@ GeoIndexIterator::GeoIndexIterator(LogicalCollection* collection,
       // lookup will hold the inforamtion if this is a cursor for
       // near/within and the reference point
       //_lookups(trx, node, reference, index->fields()),
-      _lookupResult(nullptr),
-      _posInBuffer(0) {
-    //_index->lookup(_trx, _lookups.lookup(), _buffer);
-}
+      _cursor(nullptr)
+    {}
 
 IndexLookupResult GeoIndexIterator::next() {
-  if (!_lookupResult){
-    _lookupResult = _index->nearQuery(_trx,0,0,10);
+  if (!_cursor){
+    createCursor(0,0);
   }
-  //implement
-  if (_posInBuffer < _lookupResult->length){
-    //is data the revision id?
-    return IndexLookupResult(GeoIndex::toRevision(_lookupResult->coordinates[_posInBuffer++].data));
+
+  auto coords = std::unique_ptr<GeoCoordinates>(::GeoIndex_ReadCursor(_cursor,1));
+  if(coords && coords->length){
+    auto revision = ::GeoIndex::toRevision(coords->coordinates[0].data);
+    return IndexLookupResult{revision};
   }
   // if there are no more results we return the default constructed IndexLookupResult
   return IndexLookupResult{};
 }
 
-// optional
-// void GeoIndexIterator::nextBabies(std::vector<IndexLookupResult>& result, size_t atMost) {
-//   //implement provide fast implementation
-// }
+void GeoIndexIterator::nextBabies(std::vector<IndexLookupResult>& result, size_t batchSize) {
+  if (!_cursor){
+    createCursor(0,0);
+  }
+
+  result.clear();
+  if (batchSize > 0) {
+    auto coords = std::unique_ptr<GeoCoordinates>(::GeoIndex_ReadCursor(_cursor,batchSize));
+    size_t length = coords ? coords->length : 0;
+    if (!length){
+      return;
+    }
+
+    for(std::size_t index = 0; index < length; ++index){
+      result.emplace_back(IndexLookupResult(::GeoIndex::toRevision(coords->coordinates[index].data)));
+    }
+  }
+}
+ 
+::GeoCursor* GeoIndexIterator::replaceCursor(::GeoCursor* c){
+  if(_cursor){
+    ::GeoIndex_CursorFree(_cursor);
+  }
+ _cursor = c;
+ return _cursor;
+}
+
+::GeoCursor* GeoIndexIterator::createCursor(double lat, double lon){
+  ::GeoCoordinate coor{lat, lon, 0};
+  return replaceCursor(::GeoIndex_NewCursor(_index->_geoIndex, &coor));
+}
 
 /// @brief creates an IndexIterator for the given Condition
 IndexIterator* GeoIndex::iteratorForCondition(
@@ -76,8 +103,7 @@ IndexIterator* GeoIndex::iteratorForCondition(
 
 
 void GeoIndexIterator::reset() {
-  _lookupResult = nullptr;
-  _posInBuffer = 0;
+  replaceCursor(nullptr);
 }
 
 GeoIndex::GeoIndex(TRI_idx_iid_t iid, arangodb::LogicalCollection* collection,
diff --git a/arangod/Indexes/GeoIndex.h b/arangod/Indexes/GeoIndex.h
index 3d0d309778..daa0a26a93 100644
--- a/arangod/Indexes/GeoIndex.h
+++ b/arangod/Indexes/GeoIndex.h
@@ -42,7 +42,7 @@ class GeoIndex;
 
 class GeoIndexIterator final : public IndexIterator {
  public:
-  
+
 /// @brief Construct an GeoIndexIterator based on Ast Conditions
   GeoIndexIterator(LogicalCollection* collection, arangodb::Transaction* trx, 
                     ManagedDocumentResult* mmdr,
@@ -50,24 +50,29 @@ class GeoIndexIterator final : public IndexIterator {
                     arangodb::aql::AstNode const*,
                     arangodb::aql::Variable const*);
 
-  ~GeoIndexIterator() = default;
-  
+  ~GeoIndexIterator() {
+    replaceCursor(nullptr);
+  };
+
   char const* typeName() const override { return "geo-index-iterator"; }
 
   IndexLookupResult next() override;
 
-  //void nextBabies(std::vector<IndexLookupResult>&, size_t) override;
+  void nextBabies(std::vector<IndexLookupResult>&, size_t) override;
 
   void reset() override;
 
  private:
+  ::GeoCursor* replaceCursor(::GeoCursor* c);
+  ::GeoCursor* createCursor(double lat, double lon);
+
   GeoIndex const* _index;
+  ::GeoCursor* _cursor;
   //LookupBuilder _lookups;
-  GeoCoordinates* _lookupResult;
-  size_t _posInBuffer;
 };
 
 class GeoIndex final : public Index {
+friend class GeoIndexIterator;
  public:
   GeoIndex() = delete;