SERVER-30967 Add $binarySize expression

1 files changed, 39 insertions, 7 deletions

diff --git a/src/mongo/db/pipeline/expression.cpp b/src/mongo/db/pipeline/expression.cpp
index 19658f2e005..ee960534f0e 100644
--- a/src/mongo/db/pipeline/expression.cpp
+++ b/src/mongo/db/pipeline/expression.cpp
@@ -4416,20 +4416,26 @@ const char* ExpressionSubstrCP::getOpName() const {
 
 /* ----------------------- ExpressionStrLenBytes ------------------------- */
 
+namespace {
+Value strLenBytes(StringData str) {
+    size_t strLen = str.size();
+
+    uassert(34470,
+            "string length could not be represented as an int.",
+            strLen <= std::numeric_limits<int>::max());
+    return Value(static_cast<int>(strLen));
+}
+}  // namespace
+
 Value ExpressionStrLenBytes::evaluate(const Document& root, Variables* variables) const {
     Value str(_children[0]->evaluate(root, variables));
 
     uassert(34473,
             str::stream() << "$strLenBytes requires a string argument, found: "
                           << typeName(str.getType()),
-            str.getType() == String);
-
-    size_t strLen = str.getString().size();
+            str.getType() == BSONType::String);
 
-    uassert(34470,
-            "string length could not be represented as an int.",
-            strLen <= std::numeric_limits<int>::max());
-    return Value(static_cast<int>(strLen));
+    return strLenBytes(str.getStringData());
 }
 
 REGISTER_EXPRESSION(strLenBytes, ExpressionStrLenBytes::parse);
@@ -4437,6 +4443,32 @@ const char* ExpressionStrLenBytes::getOpName() const {
     return "$strLenBytes";
 }
 
+/* -------------------------- ExpressionBinarySize ------------------------------ */
+
+Value ExpressionBinarySize::evaluate(const Document& root, Variables* variables) const {
+    Value arg = _children[0]->evaluate(root, variables);
+    if (arg.nullish()) {
+        return Value(BSONNULL);
+    }
+
+    uassert(51276,
+            str::stream() << "$binarySize requires a string or BinData argument, found: "
+                          << typeName(arg.getType()),
+            arg.getType() == BSONType::BinData || arg.getType() == BSONType::String);
+
+    if (arg.getType() == BSONType::String) {
+        return strLenBytes(arg.getStringData());
+    }
+
+    BSONBinData binData = arg.getBinData();
+    return Value(binData.length);
+}
+
+REGISTER_EXPRESSION(binarySize, ExpressionBinarySize::parse);
+const char* ExpressionBinarySize::getOpName() const {
+    return "$binarySize";
+}
+
 /* ----------------------- ExpressionStrLenCP ------------------------- */
 
 Value ExpressionStrLenCP::evaluate(const Document& root, Variables* variables) const {