removal of aggregate_legacy + new cursor interface

o made aggregate work for wire_version 0 or 2
o Added in mongoc_cursor_interface_t and a synthetic cursor stub to
  handle the aggregate modes.

Author: hanumantmk

doc/mongoc_api.txt

@@ -4,8 +4,7 @@ mongoc_collection_aggregate(3)
 
 NAME
 ----
-mongoc_collection_aggregate, mongoc_collection_aggregate_legacy - Execute an
-'aggregation' query
+mongoc_collection_aggregate - Execute an 'aggregation' query
 
 
 SYNOPSIS
@@ -17,14 +16,6 @@ mongoc_collection_aggregate (mongoc_collection_t       *collection,
                              mongoc_query_flags_t       flags,
                              const bson_t              *pipeline,
                              const mongoc_read_prefs_t *read_prefs)
-
-bson_bool_t
-mongoc_collection_aggregate_legacy (mongoc_collection_t       *collection,
-                                    mongoc_query_flags_t       flags,
-                                    const bson_t              *pipeline,
-                                    const mongoc_read_prefs_t *read_prefs,
-                                    bson_t                    *reply,
-                                    bson_error_t              *error);
 -----------------------
 
 
@@ -35,26 +26,23 @@ on the underlying 'collection'.  The bson 'pipeline' is not validated, simply
 passed along as appropriate to the server.  As such, compatibility and errors
 should be validated in the appropriate server documentation.
 
-'flags' are the same as in linkmongoc:mongoc_collection_find[3].
+In the case of older server versions, < v2.5, the returned cursor is a
+synthetic iterator over the result set.  This provides a limitation insofar as
+returned documents can be no larger than 16MB.  When connecting to newer
+servers this limitation doesn't exist.  The specific test is for wire_version >
+0.
 
-The difference between _mongoc_collection_aggregate()_ and
-_mongoc_collection_aggregate_legacy()_ has to do with currenly non-discoverable
-changes in the aggegation api between mongodb 2.4 and 2.6.  The legacy api
-returns values in 'reply', the non-legacy version returns a cursor.
+'flags' are the same as in linkmongoc:mongoc_collection_find[3].
 
 RETURN VALUE
 ------------
 The _mongoc_collection_aggregate()_ function returns a new
 linkmongoc:mongoc_cursor[7] if successful.  It returns NULL in the event of
 failure.
 
-The _mongoc_collection_aggregate_legacy()_ function returns true if successful
-and places the output value in 'reply'.
-
 ERRORS
 ------
-errors are detected through active use of the linkmongoc:mongoc_cursor[7] or
-through 'error'.
+errors are detected through active use of the linkmongoc:mongoc_cursor[7].
 
 
 SEE ALSO

doc/mongoc_collection_aggregate.txt

@@ -52,6 +52,8 @@ NOINST_H_FILES = \
 	mongoc/mongoc-collection-private.h \
 	mongoc/mongoc-counters-private.h \
 	mongoc/mongoc-cursor-private.h \
+	mongoc/mongoc-cursor-array-private.h \
+	mongoc/mongoc-cursor-cursorid-private.h \
 	mongoc/mongoc-cluster-private.h \
 	mongoc/mongoc-database-private.h \
 	mongoc/mongoc-init-private.h \
@@ -84,6 +86,8 @@ libmongoc_priv_la_SOURCES = \
 	mongoc/mongoc-collection.c \
 	mongoc/mongoc-counters.c \
 	mongoc/mongoc-cursor.c \
+	mongoc/mongoc-cursor-array.c \
+	mongoc/mongoc-cursor-cursorid.c \
 	mongoc/mongoc-database.c \
 	mongoc/mongoc-init.c \
 	mongoc/mongoc-gridfs.c \

doc/mongoc_collection_aggregate_legacy.txt

@@ -18,7 +18,6 @@ mongoc_client_set_read_prefs
 mongoc_client_set_ssl_opts
 mongoc_client_set_write_concern
 mongoc_collection_aggregate
-mongoc_collection_aggregate_legacy
 mongoc_collection_command
 mongoc_collection_command_simple
 mongoc_collection_count

doc/mongoc_symbols.txt

@@ -43,7 +43,7 @@
 
 
 #define MIN_WIRE_VERSION 0
-#define MAX_WIRE_VERSION 0
+#define MAX_WIRE_VERSION 2
 
 
 #ifndef DEFAULT_SOCKET_TIMEOUT_MSEC
@@ -113,13 +113,15 @@ _mongoc_cluster_negotiate_wire_version (mongoc_cluster_t *cluster)
    for (i = 0; i < MONGOC_CLUSTER_MAX_NODES; i++) {
       node = &cluster->nodes[i];
 
-      if ((node->min_wire_version > max_wire_version) ||
-          (node->max_wire_version < min_wire_version)) {
-         RETURN (FALSE);
-      }
+      if (node->stream) {
+         if ((node->min_wire_version > max_wire_version) ||
+             (node->max_wire_version < min_wire_version)) {
+            RETURN (FALSE);
+         }
 
-      min_wire_version = MAX (min_wire_version, node->min_wire_version);
-      max_wire_version = MIN (max_wire_version, node->max_wire_version);
+         min_wire_version = MAX (min_wire_version, node->min_wire_version);
+         max_wire_version = MIN (max_wire_version, node->max_wire_version);
+      }
    }
 
    BSON_ASSERT (min_wire_version <= max_wire_version);