Port Slime injection to Java

4 files changed, 227 insertions, 9 deletions

diff --git a/vespajlib/src/main/java/com/yahoo/slime/Injector.java b/vespajlib/src/main/java/com/yahoo/slime/Injector.java
new file mode 100644
index 00000000000..3e507cf29c2
--- /dev/null
+++ b/vespajlib/src/main/java/com/yahoo/slime/Injector.java
@@ -0,0 +1,84 @@
+// Copyright 2019 Oath Inc. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
+package com.yahoo.slime;
+
+/**
+ * @author hakonhall
+ */
+public class Injector {
+    /**
+     * Inject a slime sub-structure described by an Inspector into a slime
+     * structure where the insertion point is described by an
+     * Inserter. This will copy all the values represented by the
+     * Inspector into the position described by the Inserter. Note that
+     * this can be used to either copy data from one Slime structure to
+     * another, or to copy data internally within a single slime
+     * structure. If the Inspector contains the insertion point it will
+     * only be expanded once to avoid infinite recursion.
+     *
+     * @param inspector what to inject
+     * @param inserter where to inject
+     **/
+    public void inject(Inspector inspector, Inserter inserter) {
+        if (inspector.valid()) {
+            injectValue(inserter, inspector, null);
+        }
+    }
+
+    private void injectValue(Inserter inserter, Inspector inspector, Inspector guard) {
+        switch (inspector.type()) {
+            case NIX:    inserter.insertNIX(); break;
+            case BOOL:   inserter.insertBOOL(inspector.asBool()); break;
+            case LONG:   inserter.insertLONG(inspector.asLong()); break;
+            case DOUBLE: inserter.insertDOUBLE(inspector.asDouble()); break;
+            case STRING: inserter.insertSTRING(inspector.asString()); break;
+            case DATA:   inserter.insertDATA(inspector.asData()); break;
+            case ARRAY:  injectArray(inserter, inspector, guard); break;
+            case OBJECT: injectObject(inserter, inspector, guard); break;
+            default:     throw new IllegalArgumentException("Unknown type " + inspector.type());
+        }
+    }
+
+    private void injectArray(Inserter inserter, Inspector inspector, Inspector guard) {
+        Cursor cursor = inserter.insertARRAY();
+        ArrayTraverser arrayTraverser = new NestedInjector(cursor, guard != null ? guard : cursor);
+        inspector.traverse(arrayTraverser);
+    }
+
+    private void injectObject(Inserter inserter, Inspector inspector, Inspector guard) {
+        Cursor cursor = inserter.insertOBJECT();
+        ObjectTraverser objectTraverser = new NestedInjector(cursor, guard != null ? guard : cursor);
+        inspector.traverse(objectTraverser);
+    }
+
+    private class NestedInjector implements ArrayTraverser, ObjectTraverser {
+        private final Cursor cursor;
+        private final Inspector guard;
+
+        public NestedInjector(Cursor cursor, Inspector guard) {
+            this.cursor = cursor;
+            this.guard = guard;
+        }
+
+        @Override
+        public void entry(int idx, Inspector inspector) {
+            if (inspector == guard) {
+                return;
+            }
+
+            var inserter = new ArrayInserter();
+            inserter.adjust(cursor);
+            injectValue(inserter, inspector, guard);
+        }
+
+        @Override
+        public void field(String name, Inspector inspector) {
+            if (inspector == guard) {
+                return;
+            }
+
+            var inserter = new ObjectInserter();
+            inserter.adjust(cursor, name);
+            injectValue(inserter, inspector, guard);
+        }
+    }
+}
diff --git a/vespajlib/src/main/java/com/yahoo/slime/Inspector.java b/vespajlib/src/main/java/com/yahoo/slime/Inspector.java
index 99489faca47..ca2e678c152 100644
--- a/vespajlib/src/main/java/com/yahoo/slime/Inspector.java
+++ b/vespajlib/src/main/java/com/yahoo/slime/Inspector.java
@@ -131,4 +131,11 @@ public interface Inspector {
      */
     Inspector field(String name);
 
+    /**
+     * Tests whether this is equal to Inspector.
+     *
+     * @param that inspector.
+     * @return true if they are equal.
+     */
+    boolean equalTo(Inspector that);
 }
diff --git a/vespajlib/src/main/java/com/yahoo/slime/ObjectInserter.java b/vespajlib/src/main/java/com/yahoo/slime/ObjectInserter.java
index 3e0073beccd..450b5271db4 100644
--- a/vespajlib/src/main/java/com/yahoo/slime/ObjectInserter.java
+++ b/vespajlib/src/main/java/com/yahoo/slime/ObjectInserter.java
@@ -1,6 +1,8 @@
 // Copyright 2017 Yahoo Holdings. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
 package com.yahoo.slime;
 
+import java.util.Optional;
+
 /**
  * Helper class for inserting values into an ObjectValue.
  * For justification read Inserter documentation.
@@ -8,18 +10,64 @@ package com.yahoo.slime;
 final class ObjectInserter implements Inserter {
     private Cursor target;
     private int symbol;
+    private Optional<String> symbolName = Optional.empty();
+
     public final ObjectInserter adjust(Cursor c, int sym) {
         target = c;
         symbol = sym;
+        symbolName = Optional.empty();
+        return this;
+    }
+
+    public final ObjectInserter adjust(Cursor c, String name) {
+        target = c;
+        symbol = -1;
+        symbolName = Optional.of(name);
         return this;
     }
-    public final Cursor insertNIX()                { return target.setNix(symbol); }
-    public final Cursor insertBOOL(boolean value)  { return target.setBool(symbol, value); }
-    public final Cursor insertLONG(long value)     { return target.setLong(symbol, value); }
-    public final Cursor insertDOUBLE(double value) { return target.setDouble(symbol, value); }
-    public final Cursor insertSTRING(String value) { return target.setString(symbol, value); }
-    public final Cursor insertSTRING(byte[] utf8)  { return target.setString(symbol, utf8); }
-    public final Cursor insertDATA(byte[] value)   { return target.setData(symbol, value); }
-    public final Cursor insertARRAY()              { return target.setArray(symbol); }
-    public final Cursor insertOBJECT()             { return target.setObject(symbol); }
+
+    public final Cursor insertNIX()                {
+        return symbolName.map(name -> target.setNix(name))
+                     .orElseGet(() -> target.setNix(symbol));
+    }
+
+    public final Cursor insertBOOL(boolean value)  {
+        return symbolName.map(name -> target.setBool(name, value))
+                     .orElseGet(() -> target.setBool(symbol, value));
+    }
+
+    public final Cursor insertLONG(long value)  {
+        return symbolName.map(name -> target.setLong(name, value))
+                     .orElseGet(() -> target.setLong(symbol, value));
+    }
+
+    public final Cursor insertDOUBLE(double value)  {
+        return symbolName.map(name -> target.setDouble(name, value))
+                     .orElseGet(() -> target.setDouble(symbol, value));
+    }
+
+    public final Cursor insertSTRING(String value)  {
+        return symbolName.map(name -> target.setString(name, value))
+                     .orElseGet(() -> target.setString(symbol, value));
+    }
+
+    public final Cursor insertSTRING(byte[] utf8)  {
+        return symbolName.map(name -> target.setString(name, utf8))
+                     .orElseGet(() -> target.setString(symbol, utf8));
+    }
+
+    public final Cursor insertDATA(byte[] value)  {
+        return symbolName.map(name -> target.setData(name, value))
+                     .orElseGet(() -> target.setData(symbol, value));
+    }
+
+    public final Cursor insertARRAY()  {
+        return symbolName.map(name -> target.setArray(name))
+                     .orElseGet(() -> target.setArray(symbol));
+    }
+
+    public final Cursor insertOBJECT()  {
+        return symbolName.map(name -> target.setObject(name))
+                     .orElseGet(() -> target.setObject(symbol));
+    }
 }
diff --git a/vespajlib/src/main/java/com/yahoo/slime/Value.java b/vespajlib/src/main/java/com/yahoo/slime/Value.java
index 51a8262333b..183c659c35a 100644
--- a/vespajlib/src/main/java/com/yahoo/slime/Value.java
+++ b/vespajlib/src/main/java/com/yahoo/slime/Value.java
@@ -3,6 +3,7 @@ package com.yahoo.slime;
 
 
 import java.io.ByteArrayOutputStream;
+import java.util.Arrays;
 
 /**
  * Common implementation for all value types.
@@ -84,4 +85,82 @@ abstract class Value implements Cursor {
             return "null";
         }
     }
+
+    private static class Equal {
+        protected final Inspector rhsInspector;
+
+        protected boolean equal = true;
+
+        public Equal(Inspector rhsInspector) { this.rhsInspector = rhsInspector; }
+
+        public boolean isEqual() { return equal; }
+    }
+
+    private static class EqualArray extends Equal implements ArrayTraverser {
+        public EqualArray(Inspector rhsInspector) { super(rhsInspector); }
+
+        @Override
+        public void entry(int idx, Inspector inspector) {
+            if (equal) {
+                equal = inspector.equalTo(rhsInspector.entry(idx));
+            }
+        }
+    }
+
+    private static class EqualObject extends Equal implements ObjectTraverser {
+        public EqualObject(Inspector rhsInspector) { super(rhsInspector); }
+
+        @Override
+        public void field(String name, Inspector inspector) {
+            if (equal) {
+                equal = inspector.equalTo(rhsInspector.field(name));
+            }
+        }
+    }
+
+    @Override
+    public boolean equalTo(Inspector that) {
+        boolean equal = type() == that.type();
+
+        if (equal) {
+            switch (type()) {
+                case NIX:
+                    break;
+                case BOOL:
+                    equal = asBool() == that.asBool();
+                    break;
+                case LONG:
+                    equal = asLong() == that.asLong();
+                    break;
+                case DOUBLE:
+                    equal = Double.compare(asDouble(), that.asDouble()) == 0;
+                    break;
+                case STRING:
+                    equal = asString().equals(that.asString());
+                    break;
+                case DATA:
+                    equal = Arrays.equals(asData(), that.asData());
+                    break;
+                case ARRAY:
+                {
+                    var traverser = new EqualArray(that);
+                    traverse(traverser);
+                    equal = traverser.isEqual() && (entries() == that.entries());
+                }
+                break;
+                case OBJECT:
+                {
+                    var traverser = new EqualObject(that);
+                    traverse(traverser);
+                    equal = traverser.isEqual() && (fields() == that.fields());
+                }
+                break;
+                default:
+                    assert(false);
+                    break;
+            }
+        }
+
+        return equal;
+    }
 }