Reader type enforcement

Robert Guo · rozza · commit 992fa34b8732 · 2014-08-14T16:49:18.000+01:00
Enforces getBsonType() only gets called when state is TYPE in the BsonDocumentReader. This ensures the
DocumentReader, BinaryReader and JsonReader behave the same way.
diff --git a/bson/src/main/org/bson/BsonDocumentReader.java b/bson/src/main/org/bson/BsonDocumentReader.java
@@ -169,6 +169,10 @@ public BsonType readBsonType() {
             return getCurrentBsonType();
         }
 
+        if (getState() != State.TYPE) {
+            throwInvalidState("ReadBSONType", State.TYPE);
+        }
+
         switch (getContext().getContextType()) {
             case ARRAY:
                 currentValue = getContext().getNextValue();
diff --git a/bson/src/test/org/bson/BsonDocumentReaderSpecification.groovy b/bson/src/test/org/bson/BsonDocumentReaderSpecification.groovy
@@ -19,9 +19,20 @@ package org.bson
 import org.bson.codecs.BsonDocumentCodec
 import org.bson.codecs.DecoderContext
 import org.bson.types.ObjectId
+import spock.lang.Shared
 import spock.lang.Specification
 
 class BsonDocumentReaderSpecification extends Specification {
+
+    @Shared BsonDocument nullDoc
+
+    def setup() {
+        nullDoc = new BsonDocument([
+                new BsonElement('null', new BsonNull())
+        ])
+    }
+
+
     def 'should read all types'() {
         given:
         def doc = new BsonDocument(
@@ -50,13 +61,39 @@ class BsonDocumentReaderSpecification extends Specification {
                         new BsonElement('document', new BsonDocument('a', new BsonInt32(1)))
                 ])
 
-
         when:
         def decodedDoc = new BsonDocumentCodec().decode(new BsonDocumentReader(doc), DecoderContext.builder().build())
 
         then:
         decodedDoc == doc
     }
 
+    def 'should fail, ReadBSONType can only be called when State is TYPE, not VALUE'() {
+        given:
+        def reader = new BsonDocumentReader(nullDoc)
+
+        when:
+        reader.readStartDocument()
+        reader.readBsonType()
+        reader.readName()
+        reader.readBsonType()
+
+        then:
+        thrown(BsonInvalidOperationException)
+    }
+
+    def 'should fail, ReadBSONType can only be called when State is TYPE, not NAME'() {
+        given:
+        def reader = new BsonDocumentReader(nullDoc)
+
+        when:
+        reader.readStartDocument()
+        reader.readBsonType()
+        reader.readBsonType()
+
+        then:
+        thrown(BsonInvalidOperationException)
+    }
+
 
 }
