Merge pull request #177 from NordicSemiconductor/bugfix/canonical-cbor

Fixed encoding CBOR in canonical format

mcumgr-core/build.gradle

@@ -53,8 +53,11 @@ dependencies {
 
     // Import CBOR parser - version 2.14+ requires Android 8
     // See: https://github.com/NordicSemiconductor/Android-nRF-Connect-Device-Manager/issues/135
+    //noinspection GradleDependency
     implementation 'com.fasterxml.jackson.dataformat:jackson-dataformat-cbor:2.13.5' // don't update
+    //noinspection GradleDependency
     implementation 'com.fasterxml.jackson.core:jackson-core:2.13.5' // don't update
+    //noinspection GradleDependency
     implementation 'com.fasterxml.jackson.core:jackson-databind:2.13.5' // don't update
 
     // Test

mcumgr-core/src/main/java/io/runtime/mcumgr/util/CBOR.java

@@ -20,7 +20,7 @@
 
 @SuppressWarnings("unused")
 public class CBOR {
-    private final static CBORFactory sFactory = new CBORFactory();
+    private final static CBORFactory sFactory = new CanonicalCBORFactory();
 
     public static byte[] toBytes(Object obj) throws IOException {
         ObjectMapper mapper = new ObjectMapper(sFactory);

mcumgr-core/src/main/java/io/runtime/mcumgr/util/CanonicalCBORFactory.java

@@ -0,0 +1,53 @@
+package io.runtime.mcumgr.util;
+
+import com.fasterxml.jackson.core.JsonEncoding;
+import com.fasterxml.jackson.core.ObjectCodec;
+import com.fasterxml.jackson.core.io.IOContext;
+import com.fasterxml.jackson.dataformat.cbor.CBORConstants;
+import com.fasterxml.jackson.dataformat.cbor.CBORFactory;
+import com.fasterxml.jackson.dataformat.cbor.CBORGenerator;
+
+import java.io.IOException;
+import java.io.OutputStream;
+
+/**
+ * This class is a copy of {@link CBORFactory} with the only difference
+ * that it returns {@link CanonicalCBORGenerator} instead of {@link CBORGenerator}.
+ */
+public class CanonicalCBORFactory extends CBORFactory {
+
+    @Override
+    public CBORGenerator createGenerator(OutputStream out, JsonEncoding enc) throws IOException {
+        final IOContext ctxt = _createContext(_createContentReference(out), false);
+        return _createCBORGenerator(ctxt,
+                _generatorFeatures, _formatGeneratorFeatures, _objectCodec,
+                _decorate(out, ctxt));
+    }
+
+    @Override
+    public CBORGenerator createGenerator(OutputStream out) throws IOException {
+        final IOContext ctxt = _createContext(_createContentReference(out), false);
+        return _createCBORGenerator(ctxt,
+                _generatorFeatures, _formatGeneratorFeatures, _objectCodec,
+                _decorate(out, ctxt));
+    }
+
+    @Override
+    protected CBORGenerator _createUTF8Generator(OutputStream out, IOContext ctxt) throws IOException {
+        return _createCBORGenerator(ctxt,
+                _generatorFeatures, _formatGeneratorFeatures, _objectCodec, out);
+    }
+
+    // These methods are required to make the overriding class to work:
+
+    private CBORGenerator _createCBORGenerator(IOContext ctxt,
+                                               int stdFeat, int formatFeat, ObjectCodec codec, OutputStream out) throws IOException
+    {
+        // false -> we won't manage the stream unless explicitly directed to
+        CanonicalCBORGenerator gen = new CanonicalCBORGenerator(ctxt, stdFeat, formatFeat, _objectCodec, out);
+        if (CBORGenerator.Feature.WRITE_TYPE_HEADER.enabledIn(formatFeat)) {
+            gen.writeTag(CBORConstants.TAG_ID_SELF_DESCRIBE);
+        }
+        return gen;
+    }
+}

mcumgr-core/src/main/java/io/runtime/mcumgr/util/CanonicalCBORGenerator.java

@@ -0,0 +1,83 @@
+package io.runtime.mcumgr.util;
+
+import static com.fasterxml.jackson.dataformat.cbor.CBORConstants.PREFIX_TYPE_OBJECT;
+import static com.fasterxml.jackson.dataformat.cbor.CBORConstants.SUFFIX_UINT16_ELEMENTS;
+import static com.fasterxml.jackson.dataformat.cbor.CBORConstants.SUFFIX_UINT32_ELEMENTS;
+import static com.fasterxml.jackson.dataformat.cbor.CBORConstants.SUFFIX_UINT8_ELEMENTS;
+
+import com.fasterxml.jackson.core.ObjectCodec;
+import com.fasterxml.jackson.core.io.IOContext;
+import com.fasterxml.jackson.dataformat.cbor.CBORGenerator;
+
+import java.io.IOException;
+import java.io.OutputStream;
+import java.util.Arrays;
+
+/**
+ * This class is a copy of {@link CBORGenerator} with the only difference
+ * that it writes maps in canonical form.
+ * <p>
+ * The implementation is copied from {@link CBORGenerator} at version 2.17.1, which cannot be used
+ * as 2.14+ support only Android 8+.
+ */
+public class CanonicalCBORGenerator extends CBORGenerator {
+
+    public CanonicalCBORGenerator(IOContext ctxt, int stdFeatures, int formatFeatures, ObjectCodec codec, OutputStream out) {
+        super(ctxt, stdFeatures, formatFeatures, codec, out);
+    }
+
+    public CanonicalCBORGenerator(IOContext ctxt, int stdFeatures, int formatFeatures, ObjectCodec codec, OutputStream out, byte[] outputBuffer, int offset, boolean bufferRecyclable) {
+        super(ctxt, stdFeatures, formatFeatures, codec, out, outputBuffer, offset, bufferRecyclable);
+    }
+
+    @Override
+    public void writeStartObject(Object forValue, int elementsToWrite) throws IOException {
+        _verifyValueWrite("start an object");
+        _streamWriteContext = _streamWriteContext.createChildObjectContext(forValue);
+        _pushRemainingElements();
+        _currentRemainingElements = elementsToWrite;
+        _writeLengthMarker(PREFIX_TYPE_OBJECT, elementsToWrite);
+    }
+
+    // These methods are required to make the overriding class to work:
+
+    private void _pushRemainingElements() {
+        if (_elementCounts.length == _elementCountsPtr) { // initially, as well as if full
+            _elementCounts = Arrays.copyOf(_elementCounts, _elementCounts.length+10);
+        }
+        _elementCounts[_elementCountsPtr++] = _currentRemainingElements;
+    }
+
+    private void _writeLengthMarker(int majorType, int i)
+            throws IOException {
+        _ensureRoomForOutput(5);
+        if (i < 24) {
+            _outputBuffer[_outputTail++] = (byte) (majorType + i);
+            return;
+        }
+        if (i <= 0xFF) {
+            _outputBuffer[_outputTail++] = (byte) (majorType + SUFFIX_UINT8_ELEMENTS);
+            _outputBuffer[_outputTail++] = (byte) i;
+            return;
+        }
+        final byte b0 = (byte) i;
+        i >>= 8;
+        if (i <= 0xFF) {
+            _outputBuffer[_outputTail++] = (byte) (majorType + SUFFIX_UINT16_ELEMENTS);
+            _outputBuffer[_outputTail++] = (byte) i;
+            _outputBuffer[_outputTail++] = b0;
+            return;
+        }
+        _outputBuffer[_outputTail++] = (byte) (majorType + SUFFIX_UINT32_ELEMENTS);
+        _outputBuffer[_outputTail++] = (byte) (i >> 16);
+        _outputBuffer[_outputTail++] = (byte) (i >> 8);
+        _outputBuffer[_outputTail++] = (byte) i;
+        _outputBuffer[_outputTail++] = b0;
+    }
+
+    private void _ensureRoomForOutput(int needed) throws IOException {
+        if ((_outputTail + needed) >= _outputEnd) {
+            _flushBuffer();
+        }
+    }
+}