From 4350dacd31d3fe1adf51a07cf3d59406fa2351e3 Mon Sep 17 00:00:00 2001
From: Ben Shteinfeld <ben.shteinfeld@mongodb.com>
Date: Tue, 27 Dec 2022 18:38:00 +0000
Subject: SERVER-71943 Move ABT translation to new visitor mechanism

---
 .../db/pipeline/visitors/document_source_visitor.h | 140 ---------------------
 .../document_source_visitor_registry_mongod.h      |  10 +-
 .../pipeline/visitors/document_source_walker.cpp   | 114 -----------------
 .../db/pipeline/visitors/document_source_walker.h  |  22 ----
 4 files changed, 8 insertions(+), 278 deletions(-)
 delete mode 100644 src/mongo/db/pipeline/visitors/document_source_visitor.h

(limited to 'src/mongo/db/pipeline/visitors')

diff --git a/src/mongo/db/pipeline/visitors/document_source_visitor.h b/src/mongo/db/pipeline/visitors/document_source_visitor.h
deleted file mode 100644
index 13180f1f42d..00000000000
--- a/src/mongo/db/pipeline/visitors/document_source_visitor.h
+++ /dev/null
@@ -1,140 +0,0 @@
-/**
- *    Copyright (C) 2022-present MongoDB, Inc.
- *
- *    This program is free software: you can redistribute it and/or modify
- *    it under the terms of the Server Side Public License, version 1,
- *    as published by MongoDB, Inc.
- *
- *    This program is distributed in the hope that it will be useful,
- *    but WITHOUT ANY WARRANTY; without even the implied warranty of
- *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- *    Server Side Public License for more details.
- *
- *    You should have received a copy of the Server Side Public License
- *    along with this program. If not, see
- *    <http://www.mongodb.com/licensing/server-side-public-license>.
- *
- *    As a special exception, the copyright holders give permission to link the
- *    code of portions of this program with the OpenSSL library under certain
- *    conditions as described in each individual source file and distribute
- *    linked combinations including the program with the OpenSSL library. You
- *    must comply with the Server Side Public License in all respects for
- *    all of the code used other than as permitted herein. If you modify file(s)
- *    with this exception, you may extend this exception to your version of the
- *    file(s), but you are not obligated to do so. If you do not wish to do so,
- *    delete this exception statement from your version. If you delete this
- *    exception statement from all source files in the program, then also delete
- *    it in the license file.
- */
-
-#pragma once
-
-#include "mongo/db/query/tree_walker.h"
-
-namespace mongo {
-
-class DocumentSourceBucketAuto;
-class DocumentSourceCollStats;
-class DocumentSourceCurrentOp;
-class DocumentSourceCursor;
-class DocumentSourceExchange;
-class DocumentSourceFacet;
-class DocumentSourceGeoNear;
-class DocumentSourceGeoNearCursor;
-class DocumentSourceGraphLookUp;
-class DocumentSourceGroup;
-class DocumentSourceIndexStats;
-class DocumentSourceInternalInhibitOptimization;
-class DocumentSourceInternalShardFilter;
-class DocumentSourceInternalSplitPipeline;
-class DocumentSourceInternalUnpackBucket;
-class DocumentSourceLimit;
-class DocumentSourceListCachedAndActiveUsers;
-class DocumentSourceListLocalSessions;
-class DocumentSourceListSessions;
-class DocumentSourceLookUp;
-class DocumentSourceMatch;
-class DocumentSourceMerge;
-class DocumentSourceMergeCursors;
-class DocumentSourceOperationMetrics;
-class DocumentSourceOut;
-class DocumentSourcePlanCacheStats;
-class DocumentSourceQueue;
-class DocumentSourceRedact;
-class DocumentSourceSample;
-class DocumentSourceSampleFromRandomCursor;
-class DocumentSourceSequentialDocumentCache;
-class DocumentSourceSingleDocumentTransformation;
-class DocumentSourceSkip;
-class DocumentSourceSort;
-class DocumentSourceTeeConsumer;
-class DocumentSourceTelemetry;
-class DocumentSourceUnionWith;
-class DocumentSourceUnwind;
-
-/**
- * Visitor pattern for pipeline document sources.
- *
- * This code is not responsible for traversing the tree, only for performing the double-dispatch.
- *
- * If the visitor doesn't intend to modify the tree, then the template argument 'IsConst' should be
- * set to 'true'. In this case all 'visit()' methods will take a const pointer to a visiting node.
- */
-template <bool IsConst = false>
-class DocumentSourceVisitor {
-public:
-    virtual void visit(tree_walker::MaybeConstPtr<IsConst, DocumentSourceBucketAuto> source) = 0;
-    virtual void visit(tree_walker::MaybeConstPtr<IsConst, DocumentSourceCollStats> source) = 0;
-    virtual void visit(tree_walker::MaybeConstPtr<IsConst, DocumentSourceCurrentOp> source) = 0;
-    virtual void visit(tree_walker::MaybeConstPtr<IsConst, DocumentSourceCursor> source) = 0;
-    virtual void visit(tree_walker::MaybeConstPtr<IsConst, DocumentSourceExchange> source) = 0;
-    virtual void visit(tree_walker::MaybeConstPtr<IsConst, DocumentSourceFacet> source) = 0;
-    virtual void visit(tree_walker::MaybeConstPtr<IsConst, DocumentSourceGeoNear> source) = 0;
-    virtual void visit(tree_walker::MaybeConstPtr<IsConst, DocumentSourceGeoNearCursor> source) = 0;
-    virtual void visit(tree_walker::MaybeConstPtr<IsConst, DocumentSourceGraphLookUp> source) = 0;
-    virtual void visit(tree_walker::MaybeConstPtr<IsConst, DocumentSourceGroup> source) = 0;
-    virtual void visit(tree_walker::MaybeConstPtr<IsConst, DocumentSourceIndexStats> source) = 0;
-    virtual void visit(
-        tree_walker::MaybeConstPtr<IsConst, DocumentSourceInternalInhibitOptimization> source) = 0;
-    virtual void visit(
-        tree_walker::MaybeConstPtr<IsConst, DocumentSourceInternalShardFilter> source) = 0;
-    virtual void visit(
-        tree_walker::MaybeConstPtr<IsConst, DocumentSourceInternalSplitPipeline> source) = 0;
-    virtual void visit(
-        tree_walker::MaybeConstPtr<IsConst, DocumentSourceInternalUnpackBucket> source) = 0;
-    virtual void visit(tree_walker::MaybeConstPtr<IsConst, DocumentSourceLimit> source) = 0;
-    virtual void visit(
-        tree_walker::MaybeConstPtr<IsConst, DocumentSourceListCachedAndActiveUsers> source) = 0;
-    virtual void visit(
-        tree_walker::MaybeConstPtr<IsConst, DocumentSourceListLocalSessions> source) = 0;
-    virtual void visit(tree_walker::MaybeConstPtr<IsConst, DocumentSourceListSessions> source) = 0;
-    virtual void visit(tree_walker::MaybeConstPtr<IsConst, DocumentSourceLookUp> source) = 0;
-    virtual void visit(tree_walker::MaybeConstPtr<IsConst, DocumentSourceMatch> source) = 0;
-    virtual void visit(tree_walker::MaybeConstPtr<IsConst, DocumentSourceMerge> source) = 0;
-    virtual void visit(tree_walker::MaybeConstPtr<IsConst, DocumentSourceMergeCursors> source) = 0;
-    virtual void visit(
-        tree_walker::MaybeConstPtr<IsConst, DocumentSourceOperationMetrics> source) = 0;
-    virtual void visit(tree_walker::MaybeConstPtr<IsConst, DocumentSourceOut> source) = 0;
-    virtual void visit(
-        tree_walker::MaybeConstPtr<IsConst, DocumentSourcePlanCacheStats> source) = 0;
-    virtual void visit(tree_walker::MaybeConstPtr<IsConst, DocumentSourceQueue> source) = 0;
-    virtual void visit(tree_walker::MaybeConstPtr<IsConst, DocumentSourceRedact> source) = 0;
-    virtual void visit(tree_walker::MaybeConstPtr<IsConst, DocumentSourceSample> source) = 0;
-    virtual void visit(
-        tree_walker::MaybeConstPtr<IsConst, DocumentSourceSampleFromRandomCursor> source) = 0;
-    virtual void visit(
-        tree_walker::MaybeConstPtr<IsConst, DocumentSourceSequentialDocumentCache> source) = 0;
-    virtual void visit(
-        tree_walker::MaybeConstPtr<IsConst, DocumentSourceSingleDocumentTransformation> source) = 0;
-    virtual void visit(tree_walker::MaybeConstPtr<IsConst, DocumentSourceSkip> source) = 0;
-    virtual void visit(tree_walker::MaybeConstPtr<IsConst, DocumentSourceSort> source) = 0;
-    virtual void visit(tree_walker::MaybeConstPtr<IsConst, DocumentSourceTeeConsumer> source) = 0;
-    virtual void visit(tree_walker::MaybeConstPtr<IsConst, DocumentSourceTelemetry> source) = 0;
-    virtual void visit(tree_walker::MaybeConstPtr<IsConst, DocumentSourceUnionWith> source) = 0;
-    virtual void visit(tree_walker::MaybeConstPtr<IsConst, DocumentSourceUnwind> source) = 0;
-};
-
-using DocumentSourceMutableVisitor = DocumentSourceVisitor<false>;
-using DocumentSourceConstVisitor = DocumentSourceVisitor<true>;
-
-}  // namespace mongo
diff --git a/src/mongo/db/pipeline/visitors/document_source_visitor_registry_mongod.h b/src/mongo/db/pipeline/visitors/document_source_visitor_registry_mongod.h
index b586feffa5f..3056584979e 100644
--- a/src/mongo/db/pipeline/visitors/document_source_visitor_registry_mongod.h
+++ b/src/mongo/db/pipeline/visitors/document_source_visitor_registry_mongod.h
@@ -109,6 +109,14 @@ template <typename T>
 void registerMongodVisitor(ServiceContext* service) {
     auto& registry = getDocumentSourceVisitorRegistry(service);
     registerVisitFuncs<T,
+                       // These document sources are defined in the 'query_exec' library, so having
+                       // them here causes a circular dependency. We should ideally factor them out
+                       // into their own library (or as part of libpipeline) but this requires a
+                       // large refactor of the 'query_exec' library.
+                       // It should be safe to ignore these for now as the only user of the visitor
+                       // is CQF, which won't encounter these DocumentSources.
+                       // DocumentSourceCursor,
+                       // DocumentSourceGeoNearCursor,
                        DocumentSourceBucketAuto,
                        DocumentSourceChangeStreamAddPostImage,
                        DocumentSourceChangeStreamAddPreImage,
@@ -120,12 +128,10 @@ void registerMongodVisitor(ServiceContext* service) {
                        DocumentSourceChangeStreamUnwindTransaction,
                        DocumentSourceCollStats,
                        DocumentSourceCurrentOp,
-                       DocumentSourceCursor,
                        DocumentSourceExchange,
                        DocumentSourceFacet,
                        DocumentSourceFindAndModifyImageLookup,
                        DocumentSourceGeoNear,
-                       DocumentSourceGeoNearCursor,
                        DocumentSourceGraphLookUp,
                        DocumentSourceGroup,
                        DocumentSourceIndexStats,
diff --git a/src/mongo/db/pipeline/visitors/document_source_walker.cpp b/src/mongo/db/pipeline/visitors/document_source_walker.cpp
index d10450649cc..6076aaf82e5 100644
--- a/src/mongo/db/pipeline/visitors/document_source_walker.cpp
+++ b/src/mongo/db/pipeline/visitors/document_source_walker.cpp
@@ -29,122 +29,8 @@
 
 #include "mongo/db/pipeline/visitors/document_source_walker.h"
 
-#include "mongo/base/error_codes.h"
-#include "mongo/db/pipeline/document_source_bucket_auto.h"
-#include "mongo/db/pipeline/document_source_coll_stats.h"
-#include "mongo/db/pipeline/document_source_current_op.h"
-#include "mongo/db/pipeline/document_source_cursor.h"
-#include "mongo/db/pipeline/document_source_exchange.h"
-#include "mongo/db/pipeline/document_source_facet.h"
-#include "mongo/db/pipeline/document_source_geo_near.h"
-#include "mongo/db/pipeline/document_source_geo_near_cursor.h"
-#include "mongo/db/pipeline/document_source_graph_lookup.h"
-#include "mongo/db/pipeline/document_source_group.h"
-#include "mongo/db/pipeline/document_source_index_stats.h"
-#include "mongo/db/pipeline/document_source_internal_inhibit_optimization.h"
-#include "mongo/db/pipeline/document_source_internal_shard_filter.h"
-#include "mongo/db/pipeline/document_source_internal_split_pipeline.h"
-#include "mongo/db/pipeline/document_source_internal_unpack_bucket.h"
-#include "mongo/db/pipeline/document_source_limit.h"
-#include "mongo/db/pipeline/document_source_list_cached_and_active_users.h"
-#include "mongo/db/pipeline/document_source_list_local_sessions.h"
-#include "mongo/db/pipeline/document_source_list_sessions.h"
-#include "mongo/db/pipeline/document_source_lookup.h"
-#include "mongo/db/pipeline/document_source_match.h"
-#include "mongo/db/pipeline/document_source_merge.h"
-#include "mongo/db/pipeline/document_source_operation_metrics.h"
-#include "mongo/db/pipeline/document_source_out.h"
-#include "mongo/db/pipeline/document_source_plan_cache_stats.h"
-#include "mongo/db/pipeline/document_source_queue.h"
-#include "mongo/db/pipeline/document_source_redact.h"
-#include "mongo/db/pipeline/document_source_sample.h"
-#include "mongo/db/pipeline/document_source_sample_from_random_cursor.h"
-#include "mongo/db/pipeline/document_source_sequential_document_cache.h"
-#include "mongo/db/pipeline/document_source_single_document_transformation.h"
-#include "mongo/db/pipeline/document_source_skip.h"
-#include "mongo/db/pipeline/document_source_sort.h"
-#include "mongo/db/pipeline/document_source_tee_consumer.h"
-#include "mongo/db/pipeline/document_source_telemetry.h"
-#include "mongo/db/pipeline/document_source_union_with.h"
-#include "mongo/db/pipeline/document_source_unwind.h"
-#include "mongo/s/query/document_source_merge_cursors.h"
-
 namespace mongo {
 
-template <class T>
-bool DocumentSourceWalkerLegacy::visitHelper(const DocumentSource* source) {
-    const T* concrete = dynamic_cast<const T*>(source);
-    if (concrete == nullptr) {
-        return false;
-    }
-
-    _postVisitor->visit(concrete);
-    return true;
-}
-
-void DocumentSourceWalkerLegacy::walk(const Pipeline& pipeline) {
-    const Pipeline::SourceContainer& sources = pipeline.getSources();
-
-    if (_postVisitor != nullptr) {
-        for (auto it = sources.begin(); it != sources.end(); it++) {
-            // TODO: use acceptVisitor method when DocumentSources get ability to visit.
-            // source->acceptVisitor(*_preVisitor);
-            //
-            // For now, however, we use a crutch walker which performs a series of dynamic casts.
-            // Some types are commented out because of dependency issues (e.g. not in pipeline
-            // target but in query_exec target)
-            const DocumentSource* ds = it->get();
-            const bool visited = visitHelper<DocumentSourceBucketAuto>(ds) ||
-                visitHelper<DocumentSourceBucketAuto>(ds) ||
-                visitHelper<DocumentSourceCollStats>(ds) ||
-                visitHelper<DocumentSourceCurrentOp>(ds) ||
-                // TODO: uncomment after fixing dependency
-                // visitHelper<DocumentSourceCursor>(ds) ||
-                visitHelper<DocumentSourceExchange>(ds) || visitHelper<DocumentSourceFacet>(ds) ||
-                visitHelper<DocumentSourceGeoNear>(ds) ||
-
-                // TODO: uncomment after fixing dependency
-                //! visitHelper<DocumentSourceGeoNearCursor>(ds) ||
-                visitHelper<DocumentSourceGraphLookUp>(ds) ||
-                visitHelper<DocumentSourceGroup>(ds) || visitHelper<DocumentSourceIndexStats>(ds) ||
-                visitHelper<DocumentSourceInternalInhibitOptimization>(ds) ||
-                visitHelper<DocumentSourceInternalShardFilter>(ds) ||
-                visitHelper<DocumentSourceInternalSplitPipeline>(ds) ||
-                visitHelper<DocumentSourceInternalUnpackBucket>(ds) ||
-                visitHelper<DocumentSourceLimit>(ds) ||
-                visitHelper<DocumentSourceListCachedAndActiveUsers>(ds) ||
-                visitHelper<DocumentSourceListLocalSessions>(ds) ||
-                visitHelper<DocumentSourceListSessions>(ds) ||
-                visitHelper<DocumentSourceLookUp>(ds) || visitHelper<DocumentSourceMatch>(ds) ||
-                visitHelper<DocumentSourceMerge>(ds) ||
-                // TODO: uncomment after fixing dependency
-                // visitHelper<DocumentSourceMergeCursors>(ds) ||
-                visitHelper<DocumentSourceOperationMetrics>(ds) ||
-                visitHelper<DocumentSourceOut>(ds) ||
-                visitHelper<DocumentSourcePlanCacheStats>(ds) ||
-                visitHelper<DocumentSourceQueue>(ds) || visitHelper<DocumentSourceRedact>(ds) ||
-                visitHelper<DocumentSourceSample>(ds) ||
-                visitHelper<DocumentSourceSampleFromRandomCursor>(ds) ||
-                visitHelper<DocumentSourceSequentialDocumentCache>(ds) ||
-                visitHelper<DocumentSourceSingleDocumentTransformation>(ds) ||
-                visitHelper<DocumentSourceSkip>(ds) || visitHelper<DocumentSourceSort>(ds) ||
-                visitHelper<DocumentSourceTeeConsumer>(ds) ||
-                visitHelper<DocumentSourceTelemetry>(ds) ||
-                visitHelper<DocumentSourceUnionWith>(ds) || visitHelper<DocumentSourceUnwind>(ds)
-                // TODO: uncomment after fixing dependency
-                //&& visitHelper<DocumentSourceUpdateOnAddShard>(ds)
-                ;
-
-            if (!visited) {
-                uasserted(ErrorCodes::InternalErrorNotSupported,
-                          str::stream() << "Stage is not supported: " << ds->getSourceName());
-            }
-        }
-    }
-
-    // TODO: reverse for pre-visitor
-}
-
 void DocumentSourceWalker::walk(const Pipeline& pipeline) {
     for (auto&& ds : pipeline.getSources()) {
         // Perform double-dispatch based on the visitor context and document source types by
diff --git a/src/mongo/db/pipeline/visitors/document_source_walker.h b/src/mongo/db/pipeline/visitors/document_source_walker.h
index 0c8702ce9ad..e13f1e38d30 100644
--- a/src/mongo/db/pipeline/visitors/document_source_walker.h
+++ b/src/mongo/db/pipeline/visitors/document_source_walker.h
@@ -31,32 +31,10 @@
 
 #include "mongo/db/pipeline/document_source.h"
 #include "mongo/db/pipeline/pipeline.h"
-#include "mongo/db/pipeline/visitors/document_source_visitor.h"
 #include "mongo/db/pipeline/visitors/document_source_visitor_registry.h"
 
 namespace mongo {
 
-/**
- * DEPRECATED: Use 'DocumentSourceWalker' instead.
- * A document source walker.
- * TODO SERVER-71943: Delete this class.
- */
-class DocumentSourceWalkerLegacy final {
-public:
-    DocumentSourceWalkerLegacy(DocumentSourceConstVisitor* preVisitor,
-                               DocumentSourceConstVisitor* postVisitor)
-        : _preVisitor{preVisitor}, _postVisitor{postVisitor} {}
-
-    void walk(const Pipeline& pipeline);
-
-private:
-    template <class T>
-    bool visitHelper(const DocumentSource* source);
-
-    DocumentSourceConstVisitor* _preVisitor;
-    DocumentSourceConstVisitor* _postVisitor;
-};
-
 /**
  * A walker over a DocumentSource pipeline. See the DocumentSourceVisitorRegistry header for details
  * about why this walker does not use the typical "visitor" interface.
-- 
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