add NonBlockingByteBufferJsonParser (and refactor some NonBlockingJsonParser code to make it more extensible) (#795)

Author: pjfanning

src/main/java/com/fasterxml/jackson/core/JsonFactory.java

@@ -12,6 +12,7 @@
 import com.fasterxml.jackson.core.format.MatchStrength;
 import com.fasterxml.jackson.core.io.*;
 import com.fasterxml.jackson.core.json.*;
+import com.fasterxml.jackson.core.json.async.NonBlockingByteBufferJsonParser;
 import com.fasterxml.jackson.core.json.async.NonBlockingJsonParser;
 import com.fasterxml.jackson.core.sym.ByteQuadsCanonicalizer;
 import com.fasterxml.jackson.core.sym.CharsToNameCanonicalizer;
@@ -1241,6 +1242,33 @@ public JsonParser createNonBlockingByteArrayParser() throws IOException
         return new NonBlockingJsonParser(ctxt, _parserFeatures, can);
     }
 
+    /**
+     * Optional method for constructing parser for non-blocking parsing
+     * via {@link com.fasterxml.jackson.core.async.ByteBufferFeeder}
+     * interface (accessed using {@link JsonParser#getNonBlockingInputFeeder()}
+     * from constructed instance).
+     *<p>
+     * If this factory does not support non-blocking parsing (either at all,
+     * or from byte array),
+     * will throw {@link UnsupportedOperationException}.
+     *<p>
+     * Note that JSON-backed factory only supports parsing of UTF-8 encoded JSON content
+     * (and US-ASCII since it is proper subset); other encodings are not supported
+     * at this point.
+     *
+     * @since 2.14
+     */
+    @Override
+    public JsonParser createNonBlockingByteBufferParser() throws IOException
+    {
+        // 17-May-2017, tatu: Need to take care not to accidentally create JSON parser
+        //   for non-JSON input:
+        _requireJSONFactory("Non-blocking source not (yet?) supported for this format (%s)");
+        IOContext ctxt = _createNonBlockingContext(null);
+        ByteQuadsCanonicalizer can = _byteSymbolCanonicalizer.makeChild(_factoryFeatures);
+        return new NonBlockingByteBufferJsonParser(ctxt, _parserFeatures, can);
+    }
+
     /*
     /**********************************************************
     /* Generator factories

src/main/java/com/fasterxml/jackson/core/TokenStreamFactory.java

@@ -154,8 +154,42 @@ public abstract class TokenStreamFactory
     public abstract JsonParser createParser(String content) throws IOException;
     public abstract JsonParser createParser(URL url) throws IOException;
 
+    /**
+     * Optional method for constructing parser for non-blocking parsing
+     * via {@link com.fasterxml.jackson.core.async.ByteArrayFeeder}
+     * interface (accessed using {@link JsonParser#getNonBlockingInputFeeder()}
+     * from constructed instance).
+     *<p>
+     * If this factory does not support non-blocking parsing (either at all,
+     * or from byte array),
+     * will throw {@link UnsupportedOperationException}.
+     *<p>
+     * Note that JSON-backed factory only supports parsing of UTF-8 encoded JSON content
+     * (and US-ASCII since it is proper subset); other encodings are not supported
+     * at this point.
+     *
+     * @since 2.9
+     */
     public abstract JsonParser createNonBlockingByteArrayParser() throws IOException;
 
+    /**
+     * Optional method for constructing parser for non-blocking parsing
+     * via {@link com.fasterxml.jackson.core.async.ByteBufferFeeder}
+     * interface (accessed using {@link JsonParser#getNonBlockingInputFeeder()}
+     * from constructed instance).
+     *<p>
+     * If this factory does not support non-blocking parsing (either at all,
+     * or from byte array),
+     * will throw {@link UnsupportedOperationException}.
+     *<p>
+     * Note that JSON-backed factory only supports parsing of UTF-8 encoded JSON content
+     * (and US-ASCII since it is proper subset); other encodings are not supported
+     * at this point.
+     *
+     * @since 2.14
+     */
+    public abstract JsonParser createNonBlockingByteBufferParser() throws IOException;
+
     /*
     /**********************************************************************
     /* Factory methods, generators

src/main/java/com/fasterxml/jackson/core/json/async/NonBlockingByteBufferJsonParser.java

@@ -0,0 +1,91 @@
+package com.fasterxml.jackson.core.json.async;
+
+import com.fasterxml.jackson.core.async.ByteBufferFeeder;
+import com.fasterxml.jackson.core.async.NonBlockingInputFeeder;
+import com.fasterxml.jackson.core.io.IOContext;
+import com.fasterxml.jackson.core.sym.ByteQuadsCanonicalizer;
+
+import java.io.IOException;
+import java.io.OutputStream;
+import java.nio.ByteBuffer;
+import java.nio.channels.Channels;
+import java.nio.channels.WritableByteChannel;
+
+/**
+ * Non-blocking parser implementation for JSON content.
+ *<p>
+ * NOTE: only supports parsing of UTF-8 encoded content (and 7-bit US-ASCII since
+ * it is strict subset of UTF-8): other encodings are not supported.
+ */
+public class NonBlockingByteBufferJsonParser
+        extends NonBlockingUtf8JsonParserBase
+        implements ByteBufferFeeder {
+
+    private ByteBuffer _inputBuffer = ByteBuffer.wrap(NO_BYTES);
+
+    public NonBlockingByteBufferJsonParser(IOContext ctxt, int parserFeatures,
+                                           ByteQuadsCanonicalizer sym) {
+        super(ctxt, parserFeatures, sym);
+    }
+
+    @Override
+    public NonBlockingInputFeeder getNonBlockingInputFeeder() {
+        return this;
+    }
+
+    @Override
+    public void feedInput(final ByteBuffer byteBuffer) throws IOException {
+        // Must not have remaining input
+        if (_inputPtr < _inputEnd) {
+            _reportError("Still have %d undecoded bytes, should not call 'feedInput'", _inputEnd - _inputPtr);
+        }
+
+        final int start = byteBuffer.position();
+        final int end = byteBuffer.limit();
+
+        if (end < start) {
+            _reportError("Input end (%d) may not be before start (%d)", end, start);
+        }
+        // and shouldn't have been marked as end-of-input
+        if (_endOfInput) {
+            _reportError("Already closed, can not feed more input");
+        }
+        // Time to update pointers first
+        _currInputProcessed += _origBufferLen;
+
+        // Also need to adjust row start, to work as if it extended into the past wrt new buffer
+        _currInputRowStart = start - (_inputEnd - _currInputRowStart);
+
+        // And then update buffer settings
+        _currBufferStart = start;
+        _inputBuffer = byteBuffer;
+        _inputPtr = start;
+        _inputEnd = end;
+        _origBufferLen = end - start;
+    }
+
+    @Override
+    public int releaseBuffered(final OutputStream out) throws IOException {
+        final int avail = _inputEnd - _inputPtr;
+        if (avail > 0) {
+            final WritableByteChannel channel = Channels.newChannel(out);
+            channel.write(_inputBuffer);
+        }
+        return avail;
+    }
+
+    @Override
+    protected byte getNextSignedByteFromBuffer() {
+        return _inputBuffer.get(_inputPtr++);
+    }
+
+    @Override
+    protected int getNextUnsignedByteFromBuffer() {
+        return _inputBuffer.get(_inputPtr++) & 0xFF;
+    }
+
+    @Override
+    protected byte getByteFromBuffer(final int ptr) {
+        return _inputBuffer.get(ptr);
+    }
+}