Add FindVisitor (#947)

Co-authored-by: Yee <2520865+yixinglu@users.noreply.github.com>

src/util/ExpressionUtils.h

@@ -17,9 +17,8 @@
 #include "common/expression/PropertyExpression.h"
 #include "common/expression/TypeCastingExpression.h"
 #include "common/expression/UnaryExpression.h"
-#include "visitor/CollectAllExprsVisitor.h"
 #include "visitor/EvaluableExprVisitor.h"
-#include "visitor/FindAnyExprVisitor.h"
+#include "visitor/FindVisitor.h"
 #include "visitor/RewriteVisitor.h"
 
 namespace nebula {
@@ -37,19 +36,40 @@ class ExpressionUtils {
     // null for not found
     static const Expression* findAny(const Expression* self,
                                      const std::unordered_set<Expression::Kind>& expected) {
-        FindAnyExprVisitor visitor(expected);
+        auto finder = [](const Expression* expr,
+                         const std::unordered_set<Expression::Kind>& targets) -> bool {
+            if (targets.find(expr->kind()) != targets.end()) {
+                return true;
+            }
+            return false;
+        };
+        FindVisitor<Expression::Kind> visitor(finder, expected);
         const_cast<Expression*>(self)->accept(&visitor);
-        return visitor.expr();
+        auto res = visitor.results();
+
+        if (res.size() == 1) {
+            // findAny only produce one result
+            return res.front();
+        }
+
+        return nullptr;
     }
 
     // Find all expression fit any kind
     // Empty for not found any one
     static std::vector<const Expression*> collectAll(
         const Expression* self,
         const std::unordered_set<Expression::Kind>& expected) {
-        CollectAllExprsVisitor visitor(expected);
+        auto finder = [](const Expression* expr,
+                         const std::unordered_set<Expression::Kind>& targets) -> bool {
+            if (targets.find(expr->kind()) != targets.end()) {
+                return true;
+            }
+            return false;
+        };
+        FindVisitor<Expression::Kind> visitor(finder, expected, true);
         const_cast<Expression*>(self)->accept(&visitor);
-        return std::move(visitor).exprs();
+        return std::move(visitor).results();
     }
 
     static bool hasAny(const Expression* expr,

src/validator/GroupByValidator.cpp

@@ -9,7 +9,7 @@
 #include "util/AnonColGenerator.h"
 #include "util/AnonVarGenerator.h"
 #include "util/ExpressionUtils.h"
-#include "visitor/FindAnySubExprVisitor.h"
+#include "visitor/FindVisitor.h"
 
 namespace nebula {
 namespace graph {
@@ -147,13 +147,22 @@ Status GroupByValidator::groupClauseSemanticCheck() {
         groupKeys_ = yieldCols_;
     } else {
         std::unordered_set<Expression*> groupSet(groupKeys_.begin(), groupKeys_.end());
+        auto finder = [](const Expression* expr,
+                         const std::unordered_set<Expression*>& targets) -> bool {
+            for (auto* target : targets) {
+                if (*target == *expr) {
+                    return true;
+                }
+            }
+            return false;
+        };
         for (auto* expr : yieldCols_) {
             if (evaluableExpr(expr)) {
                 continue;
             }
-            FindAnySubExprVisitor groupVisitor(groupSet, true);
-            expr->accept(&groupVisitor);
-            if (!groupVisitor.found()) {
+            FindVisitor<Expression*> visitor(finder, groupSet);
+            expr->accept(&visitor);
+            if (!visitor.found()) {
                 return Status::SemanticError("Yield non-agg expression `%s' must be"
                                              " functionally dependent on items in GROUP BY clause",
                                              expr->toString().c_str());

src/visitor/CMakeLists.txt

@@ -6,13 +6,10 @@
 nebula_add_library(
     expr_visitor_obj OBJECT
     ExprVisitorImpl.cpp
-    CollectAllExprsVisitor.cpp
     DeducePropsVisitor.cpp
     DeduceTypeVisitor.cpp
     ExtractPropExprVisitor.cpp
     ExtractFilterExprVisitor.cpp
-    FindAnyExprVisitor.cpp
-    FindAnySubExprVisitor.cpp
     FoldConstantExprVisitor.cpp
     RewriteSymExprVisitor.cpp
     RewriteVisitor.cpp