RethinkDB native connector work, minor fixes.

ext/librethinkdbxx/src/cursor.h

@@ -0,0 +1,76 @@
+#pragma once
+
+#include "connection.h"
+
+namespace RethinkDB {
+
+// The response from the server, as returned by run.
+// The response is either a single datum or a stream:
+//  * If it is a stream, the cursor represents each element of the stream.
+//    - Batches are fetched from the server as needed.
+//  * If it is a single datum, is_single() returns true.
+//    - If it is an array, the cursor represents each element of that array
+//    - Otherwise, to_datum() returns the datum and iteration throws an exception.
+// The cursor can only be iterated over once, it discards data that has already been read.
+class CursorPrivate;
+class Cursor {
+public:
+    Cursor() = delete;
+    ~Cursor();
+
+    Cursor(Cursor&&);                   // movable
+    Cursor& operator=(Cursor&&);
+    Cursor(const Cursor&) = delete;     // not copyable
+    Cursor& operator=(const Cursor&) = delete;
+
+    // Returned by begin() and end()
+    class iterator {
+    public:
+        iterator(Cursor*);
+        iterator& operator++ ();
+        Datum& operator* ();
+        bool operator!= (const iterator&) const;
+
+    private:
+        Cursor *cursor;
+    };
+
+    // Consume the next element
+    Datum& next(double wait = FOREVER) const;
+
+    // Peek at the next element
+    Datum& peek(double wait = FOREVER) const;
+
+    // Call f on every element of the Cursor
+    void each(std::function<void(Datum&&)> f, double wait = FOREVER) const;
+
+    // Consume and return all elements
+    Array&& to_array() &&;
+
+    // If is_single(), returns the single datum. Otherwise returns to_array().
+    Datum to_datum() &&;
+    Datum to_datum() const &;
+
+    // Efficiently consume and return all elements
+    Array to_array() const &;
+
+    // Close the cursor
+    void close() const;
+
+    // Returns false if there are no more elements
+    bool has_next(double wait = FOREVER) const;
+
+    // Returns false if the cursor is a stream
+    bool is_single() const;
+
+    iterator begin();
+    iterator end();
+
+private:
+    explicit Cursor(CursorPrivate *dd);
+    std::unique_ptr<CursorPrivate> d;
+
+    friend class Connection;
+};
+
+}