Java indexer: emit snippets over entire surrounding statement

Summary:
Unlike the default line snippets that the Kythe server synthesizes,
these snippets may span over multiple lines to give a broader context.

Reviewers: shahms, zarko

Reviewed By: zarko

Projects: #java

Differential Revision: https://phabricator-dot-kythe-repo.appspot.com/D576

RELEASES.md

@@ -6,6 +6,9 @@ Notable changes:
  - Use proto3 JSON mapping for web requests: https://developers.google.com/protocol-buffers/docs/proto3#json
  - Java indexer: report error when indexing from compilation's source root
 
+Notable additions:
+ - Java indexer: emit (possibly multi-line) snippets over entire surrounding statement
+
 ## v0.0.15
 
 Notable changes:

kythe/java/com/google/devtools/kythe/analyzers/base/KytheEntrySets.java

@@ -22,6 +22,7 @@
 import com.google.devtools.kythe.proto.Analysis.CompilationUnit.FileInput;
 import com.google.devtools.kythe.proto.Storage.VName;
 import com.google.devtools.kythe.util.KytheURI;
+import com.google.devtools.kythe.util.Span;
 
 import java.nio.file.Path;
 import java.nio.file.Paths;
@@ -112,18 +113,31 @@ public EntrySet getBuiltin(String name) {
   }
 
   /** Returns (and emits) a new anchor node at the given location in the file. */
-  public EntrySet getAnchor(VName fileVName, int start, int end) {
-    if (start > end || start < 0) {
+  public EntrySet getAnchor(VName fileVName, Span loc) {
+    return getAnchor(fileVName, loc, null);
+  }
+
+  /**
+   * Returns (and emits) a new anchor node at the given location in the file with an optional
+   * snippet span.
+   */
+  public EntrySet getAnchor(VName fileVName, Span loc, Span snippet) {
+    if (loc == null || !loc.valid()) {
       // TODO(schroederc): reduce number of invalid anchors
       return null;
     }
-    EntrySet anchor =
+    EntrySet.Builder builder =
         newNode(NodeKind.ANCHOR)
             .setCorpusPath(CorpusPath.fromVName(fileVName))
             .addSignatureSalt(fileVName)
-            .setProperty("loc/start", "" + start)
-            .setProperty("loc/end", "" + end)
-            .build();
+            .setProperty("loc/start", "" + loc.getStart())
+            .setProperty("loc/end", "" + loc.getEnd());
+    if (snippet != null && snippet.valid()) {
+      builder
+          .setProperty("snippet/start", "" + snippet.getStart())
+          .setProperty("snippet/end", "" + snippet.getEnd());
+    }
+    EntrySet anchor = builder.build();
     emitEdge(anchor.getVName(), EdgeKind.CHILDOF, fileVName);
     return emitAndReturn(anchor);
   }

kythe/java/com/google/devtools/kythe/analyzers/java/JavaEntrySets.java

@@ -131,21 +131,25 @@ public EntrySet getWildcardNode(JCTree.JCWildcard wild) {
 
   /** Returns and emits a Java anchor for the given {@link JCTree}. */
   public EntrySet getAnchor(Positions filePositions, JCTree tree) {
-    return getAnchor(filePositions, filePositions.getStart(tree), filePositions.getEnd(tree));
+    return getAnchor(filePositions, filePositions.getSpan(tree));
   }
 
   /** Returns and emits a Java anchor for the given offset span. */
-  public EntrySet getAnchor(Positions filePositions, int start, int end) {
-    return getAnchor(lookupVName(getDigest(filePositions.getSourceFile())), start, end);
+  public EntrySet getAnchor(Positions filePositions, Span loc) {
+    return getAnchor(filePositions, loc, null);
+  }
+
+  /** Returns and emits a Java anchor for the given offset span. */
+  public EntrySet getAnchor(Positions filePositions, Span loc, Span snippet) {
+    return getAnchor(lookupVName(getDigest(filePositions.getSourceFile())), loc, snippet);
   }
 
   /** Returns and emits a Java anchor for the given identifier. */
-  public EntrySet getAnchor(Positions filePositions, Name name, int startOffset) {
+  public EntrySet getAnchor(Positions filePositions, Name name, int startOffset, Span snippet) {
     Span span = filePositions.findIdentifier(name, startOffset);
     return span == null
         ? null
-        : getAnchor(
-            lookupVName(getDigest(filePositions.getSourceFile())), span.getStart(), span.getEnd());
+        : getAnchor(lookupVName(getDigest(filePositions.getSourceFile())), span, snippet);
   }
 
   /** Returns the equivalent {@link NodeKind} for the given {@link ElementKind}. */