YAML I/O add support for validate()

MappingTrait template specializations can now have a validate() method which 
performs semantic checking. For details, see <http://llvm.org/docs/YamlIO.html>.

llvm-svn: 195286

1 files changed, 43 insertions, 3 deletions

diff --git a/llvm/unittests/Support/YAMLIOTest.cpp b/llvm/unittests/Support/YAMLIOTest.cpp
index 07d70459fb8..52a8f6b88c2 100644
--- a/llvm/unittests/Support/YAMLIOTest.cpp
+++ b/llvm/unittests/Support/YAMLIOTest.cpp
@@ -27,6 +27,13 @@ using llvm::yaml::Hex32;
 using llvm::yaml::Hex64;
 
 
+
+
+static void suppressErrorMessages(const llvm::SMDiagnostic &, void *) {
+}
+
+
+
 //===----------------------------------------------------------------------===//
 //  Test MappingTraits
 //===----------------------------------------------------------------------===//
@@ -1115,18 +1122,51 @@ TEST(YAMLIO, TestTaggedDocumentsWriteAndRead) {
 }
 
 
-
 //===----------------------------------------------------------------------===//
-//  Test error handling
+//  Test mapping validation
 //===----------------------------------------------------------------------===//
 
+struct MyValidation {
+  double value;
+};
 
+LLVM_YAML_IS_DOCUMENT_LIST_VECTOR(MyValidation)
 
-static void suppressErrorMessages(const llvm::SMDiagnostic &, void *) {
+namespace llvm {
+namespace yaml {
+  template <>
+  struct MappingTraits<MyValidation> {
+    static void mapping(IO &io, MyValidation &d) {
+        io.mapRequired("value", d.value);
+    }
+    static StringRef validate(IO &io, MyValidation &d) {
+        if (d.value < 0)
+          return "negative value";
+        return StringRef();
+    }
+  };
+ }
 }
 
 
 //
+// Test that validate() is called and complains about the negative value.
+//
+TEST(YAMLIO, TestValidatingInput) {
+  std::vector<MyValidation> docList;
+  Input yin("--- \nvalue:  3.0\n"
+            "--- \nvalue:  -1.0\n...\n",
+            NULL, suppressErrorMessages);
+  yin >> docList;
+  EXPECT_TRUE(yin.error());
+}
+
+
+//===----------------------------------------------------------------------===//
+//  Test error handling
+//===----------------------------------------------------------------------===//
+
+//
 // Test error handling of unknown enumerated scalar
 //
 TEST(YAMLIO, TestColorsReadError) {