Require names to be null-terminated

Summary:
It is conveinent to cast these to c-style strings (e.g. to pass into DebugProtocol::writeFieldBegin)

This diff adds a requirement that names contained within SyntaxGraph are null-terminated.

Reviewed By: iahs

Differential Revision: D73053809

fbshipit-source-id: 8e4eb9a839338849ba9e74f933d965695a40f8b4

Author: Pranav Thulasiram Bhat

thrift/lib/cpp2/schema/SyntaxGraph.cpp

@@ -84,6 +84,12 @@ class DefinitionKeyEqual : public std::equal_to<type::DefinitionKey> {
 
 } // namespace
 
+WithName::WithName(std::string_view name) : name_(name) {
+  FOLLY_SAFE_DCHECK(
+      name_.data()[name_.size()] == '\0',
+      "name must be backed by a null-terminated string!");
+}
+
 class Resolver final {
  private:
   friend class ::apache::thrift::schema::SyntaxGraph;

thrift/lib/cpp2/schema/SyntaxGraph.h

@@ -387,10 +387,13 @@ class Lazy {
  */
 class WithName {
  protected:
-  explicit WithName(std::string_view name) : name_(name) {}
+  // Requirement: `name` is backed by a null-terminated string (e.g. static
+  // string or std::string)
+  explicit WithName(std::string_view name);
 
   /**
    * The scoped name of this graph node.
+   * Can be assumed to be null-terminated
    */
   std::string_view name() const { return name_; }
 

thrift/lib/cpp2/schema/test/SyntaxGraphTest.cpp

@@ -173,6 +173,7 @@ TEST_F(ServiceSchemaTest, Struct) {
   EXPECT_EQ(&testStruct->program(), program.unwrap());
   EXPECT_EQ(testStruct->kind(), DefinitionNode::Kind::STRUCT);
   EXPECT_EQ(testStruct->name(), "TestStruct");
+  EXPECT_STREQ(testStruct->name().data(), "TestStruct");
   const StructNode& s = testStruct->asStruct();
   EXPECT_EQ(&s.definition(), testStruct.unwrap());
   EXPECT_EQ(s.uri(), "");
@@ -184,6 +185,7 @@ TEST_F(ServiceSchemaTest, Struct) {
       s.fields()[0].presence(), FieldNode::PresenceQualifier::UNQUALIFIED);
   EXPECT_EQ(s.fields()[0].type().asPrimitive(), Primitive::I32);
   EXPECT_EQ(s.fields()[0].name(), "field1");
+  EXPECT_STREQ(s.fields()[0].name().data(), "field1");
   EXPECT_EQ(s.fields()[0].customDefault()->as_i32(), 10);
 
   EXPECT_EQ(s.fields()[1].id(), FieldId{2});
@@ -192,6 +194,7 @@ TEST_F(ServiceSchemaTest, Struct) {
       &s.fields()[1].type().asEnum(),
       &program->definitionsByName().at("TestEnum")->asEnum());
   EXPECT_EQ(s.fields()[1].name(), "field2");
+  EXPECT_STREQ(s.fields()[1].name().data(), "field2");
   EXPECT_EQ(s.fields()[1].customDefault(), nullptr);
 }
 
@@ -204,6 +207,7 @@ TEST_F(ServiceSchemaTest, Union) {
   EXPECT_EQ(&testUnion->program(), program.unwrap());
   EXPECT_EQ(testUnion->kind(), DefinitionNode::Kind::UNION);
   EXPECT_EQ(testUnion->name(), "TestUnion");
+  EXPECT_STREQ(testUnion->name().data(), "TestUnion");
   const UnionNode& u = testUnion->asUnion();
 
   EXPECT_EQ(u.fields().size(), 2);