Remove Path from Location, ParserInputSource and bunch of other low-level classes.

This makes the code cleaner because a lot of places never read the file and thus never needed a Path in the first place. I got to this change in a bit convoluted way:

- I wanted the default tools in Android rules to point to //external:
- I wanted to make sure that that doesn't cause an error is no Android rules are built, thus I had to add some binding for them in the default WORKSPACE file
- I wanted the Android rules not to depend on Bazel core with an eye towards eventually moving them to a separate jar / Skylark code
- The default WORKSPACE file is currently composed from files extracted by the Bazel launcher which would make the Android rules depend on a very core mechanism
- I couldn't simply pass in jdk.WORKSPACE as a String because Location, ParserInputSource and a bunch of other things needed a Path, which a simple string doesn't have.

Thus, this change.

--
MOS_MIGRATED_REVID=95828839

9 files changed, 50 insertions, 52 deletions

diff --git a/src/main/java/com/google/devtools/build/lib/events/Location.java b/src/main/java/com/google/devtools/build/lib/events/Location.java
index c16c244c5d..160d4a586d 100644
--- a/src/main/java/com/google/devtools/build/lib/events/Location.java
+++ b/src/main/java/com/google/devtools/build/lib/events/Location.java
@@ -23,11 +23,11 @@ import java.io.Serializable;
 /**
  * A Location is a range of characters within a file.
  *
- * The start and end locations may be the same, in which case the Location
+ * <p>The start and end locations may be the same, in which case the Location
  * denotes a point in the file, not a range.  The path may be null, indicating
  * an unknown file.
  *
- * Implementations of Location should be optimised for speed of construction,
+ * <p>Implementations of Location should be optimised for speed of construction,
  * not speed of attribute access, as far more Locations are created during
  * parsing than are ever used to display error messages.
  */
@@ -38,10 +38,10 @@ public abstract class Location implements Serializable {
     private final PathFragment path;
     private final LineAndColumn startLineAndColumn;
 
-    private LocationWithPathAndStartColumn(Path path, int startOffSet, int endOffSet,
+    private LocationWithPathAndStartColumn(PathFragment path, int startOffSet, int endOffSet,
         LineAndColumn startLineAndColumn) {
       super(startOffSet, endOffSet);
-      this.path = path != null ? path.asFragment() : null;
+      this.path = path;
       this.startLineAndColumn = startLineAndColumn;
     }
 
@@ -60,7 +60,7 @@ public abstract class Location implements Serializable {
   /**
    * Returns a Location with a given Path, start and end offset and start line and column info. 
    */
-  public static Location fromPathAndStartColumn(Path path,  int startOffSet, int endOffSet,
+  public static Location fromPathAndStartColumn(PathFragment path,  int startOffSet, int endOffSet,
       LineAndColumn startLineAndColumn) {
     return new LocationWithPathAndStartColumn(path, startOffSet, endOffSet, startLineAndColumn);
   }
@@ -70,14 +70,17 @@ public abstract class Location implements Serializable {
    * region within the file.  Try to use a more specific location if possible.
    */
   public static Location fromFile(Path path) {
-    return fromFileAndOffsets(path, 0, 0);
+    return fromFileAndOffsets(path.asFragment(), 0, 0);
   }
 
+  public static Location fromPathFragment(PathFragment path) {
+    return fromFileAndOffsets(path, 0, 0);
+  }
   /**
    * Returns a Location relating to the subset of file 'path', starting at
    * 'startOffset' and ending at 'endOffset'.
    */
-  public static Location fromFileAndOffsets(final Path path,
+  public static Location fromFileAndOffsets(final PathFragment path,
                                             int startOffset,
                                             int endOffset) {
     return new LocationWithPathAndStartColumn(path, startOffset, endOffset, null);
@@ -113,7 +116,7 @@ public abstract class Location implements Serializable {
    * Returns the path of the file to which the start/end offsets refer.  May be
    * null if the file name information is not available.
    *
-   * This method is intentionally abstract, as a space optimisation.  Some
+   * <p>This method is intentionally abstract, as a space optimisation.  Some
    * subclass instances implement sharing of common data (e.g. tables for
    * convering offsets into line numbers) and this enables them to share the
    * Path value in the same way.
diff --git a/src/main/java/com/google/devtools/build/lib/packages/PackageFactory.java b/src/main/java/com/google/devtools/build/lib/packages/PackageFactory.java
index 02c7f03d1f..871b3d7997 100644
--- a/src/main/java/com/google/devtools/build/lib/packages/PackageFactory.java
+++ b/src/main/java/com/google/devtools/build/lib/packages/PackageFactory.java
@@ -1097,7 +1097,7 @@ public final class PackageFactory {
       EventHandler eventHandler) throws InterruptedException {
     ParserInputSource inputSource = maybeGetParserInputSource(buildFile, eventHandler);
     if (inputSource == null) {
-      return Preprocessor.Result.transientError(buildFile);
+      return Preprocessor.Result.transientError(buildFile.asFragment());
     }
     Globber globber = createLegacyGlobber(buildFile.getParentDirectory(), packageId, locator);
     try {
@@ -1128,7 +1128,7 @@ public final class PackageFactory {
     } catch (IOException e) {
       eventHandler.handle(Event.error(Location.fromFile(buildFile),
                      "preprocessing failed: " + e.getMessage()));
-      return Preprocessor.Result.transientError(buildFile);
+      return Preprocessor.Result.transientError(buildFile.asFragment());
     } catch (InterruptedException e) {
       globber.onInterrupt();
       throw e;
diff --git a/src/main/java/com/google/devtools/build/lib/packages/Preprocessor.java b/src/main/java/com/google/devtools/build/lib/packages/Preprocessor.java
index 8eda1e9dec..834fcaef36 100644
--- a/src/main/java/com/google/devtools/build/lib/packages/Preprocessor.java
+++ b/src/main/java/com/google/devtools/build/lib/packages/Preprocessor.java
@@ -17,7 +17,7 @@ import com.google.devtools.build.lib.events.EventHandler;
 import com.google.devtools.build.lib.packages.PackageFactory.Globber;
 import com.google.devtools.build.lib.syntax.Environment;
 import com.google.devtools.build.lib.syntax.ParserInputSource;
-import com.google.devtools.build.lib.vfs.Path;
+import com.google.devtools.build.lib.vfs.PathFragment;
 
 import java.io.IOException;
 import java.util.Set;
@@ -119,12 +119,12 @@ public interface Preprocessor {
           /*containsTransientErrors=*/false);
     }
 
-    public static Result invalidSyntax(Path buildFile) {
+    public static Result invalidSyntax(PathFragment buildFile) {
       return new Result(ParserInputSource.create("", buildFile), /*preprocessed=*/true,
           /*containsPersistentErrors=*/true, /*containsTransientErrors=*/false);
     }
 
-    public static Result transientError(Path buildFile) {
+    public static Result transientError(PathFragment buildFile) {
       return new Result(ParserInputSource.create("", buildFile), /*preprocessed=*/false,
           /*containsPersistentErrors=*/false, /*containsTransientErrors=*/true);
     }
diff --git a/src/main/java/com/google/devtools/build/lib/skyframe/PackageFunction.java b/src/main/java/com/google/devtools/build/lib/skyframe/PackageFunction.java
index 862e87b4fb..8aac499d6e 100644
--- a/src/main/java/com/google/devtools/build/lib/skyframe/PackageFunction.java
+++ b/src/main/java/com/google/devtools/build/lib/skyframe/PackageFunction.java
@@ -712,7 +712,7 @@ public class PackageFunction implements SkyFunction {
       List<Statement> preludeStatements, SkylarkImportResult importResult)
           throws InterruptedException {
     ParserInputSource replacementSource = replacementContents == null ? null
-        : ParserInputSource.create(replacementContents, buildFilePath);
+        : ParserInputSource.create(replacementContents, buildFilePath.asFragment());
     Package.LegacyBuilder pkgBuilder = packageFunctionCache.getIfPresent(packageId);
     if (pkgBuilder == null) {
       profiler.startTask(ProfilerTask.CREATE_PACKAGE, packageId.toString());
diff --git a/src/main/java/com/google/devtools/build/lib/syntax/BuildFileAST.java b/src/main/java/com/google/devtools/build/lib/syntax/BuildFileAST.java
index 0645cb3983..800aa65535 100644
--- a/src/main/java/com/google/devtools/build/lib/syntax/BuildFileAST.java
+++ b/src/main/java/com/google/devtools/build/lib/syntax/BuildFileAST.java
@@ -16,6 +16,7 @@ package com.google.devtools.build.lib.syntax;
 import com.google.common.collect.ImmutableCollection;
 import com.google.common.collect.ImmutableList;
 import com.google.common.collect.ImmutableSet;
+import com.google.common.hash.HashCode;
 import com.google.devtools.build.lib.events.Event;
 import com.google.devtools.build.lib.events.EventHandler;
 import com.google.devtools.build.lib.events.Location;
@@ -67,7 +68,7 @@ public class BuildFileAST extends ASTNode {
           result.statements.get(0).getLocation().getStartOffset(),
           result.statements.get(result.statements.size() - 1).getLocation().getEndOffset()));
     } else {
-      setLocation(Location.fromFile(lexer.getFilename()));
+      setLocation(Location.fromPathFragment(lexer.getFilename()));
     }
   }
 
@@ -222,7 +223,8 @@ public class BuildFileAST extends ASTNode {
     Lexer lexer = new Lexer(input, eventHandler, false);
     Parser.ParseResult result =
         Parser.parseFileForSkylark(lexer, eventHandler, locator, validationEnvironment);
-    return new BuildFileAST(lexer, ImmutableList.<Statement>of(), result, input.contentHashCode());
+    return new BuildFileAST(lexer, ImmutableList.<Statement>of(), result,
+        HashCode.fromBytes(file.getMD5Digest()).toString());
   }
 
   /**
diff --git a/src/main/java/com/google/devtools/build/lib/syntax/Lexer.java b/src/main/java/com/google/devtools/build/lib/syntax/Lexer.java
index 77cdf3f5ee..5f6c769ebb 100644
--- a/src/main/java/com/google/devtools/build/lib/syntax/Lexer.java
+++ b/src/main/java/com/google/devtools/build/lib/syntax/Lexer.java
@@ -20,7 +20,6 @@ import com.google.devtools.build.lib.events.Event;
 import com.google.devtools.build.lib.events.EventHandler;
 import com.google.devtools.build.lib.events.Location;
 import com.google.devtools.build.lib.util.Pair;
-import com.google.devtools.build.lib.vfs.Path;
 import com.google.devtools.build.lib.vfs.PathFragment;
 
 import java.util.ArrayList;
@@ -62,8 +61,8 @@ public final class Lexer {
    */
   private static class LocationInfo {
     final LineNumberTable lineNumberTable;
-    final Path filename;
-    LocationInfo(Path filename, LineNumberTable lineNumberTable) {
+    final PathFragment filename;
+    LocationInfo(PathFragment filename, LineNumberTable lineNumberTable) {
       this.filename = filename;
       this.lineNumberTable = lineNumberTable;
     }
@@ -94,8 +93,8 @@ public final class Lexer {
     this.pos = 0;
     this.parsePython = parsePython;
     this.eventHandler = eventHandler;
-    this.locationInfo = new LocationInfo(input.getPath(),
-        LineNumberTable.create(buffer, input.getPath()));
+    this.locationInfo =
+        new LocationInfo(input.getPath(), LineNumberTable.create(buffer, input.getPath()));
 
     indentStack.push(0);
     tokenize();
@@ -109,7 +108,7 @@ public final class Lexer {
    * Returns the filename from which the lexer's input came. Returns a dummy
    * value if the input came from a string.
    */
-  public Path getFilename() {
+  public PathFragment getFilename() {
     return locationInfo.filename;
   }
 
@@ -164,8 +163,8 @@ public final class Lexer {
 
     @Override
     public PathFragment getPath() {
-      Path path = lineNumberTable.getPath(getStartOffset());
-      return path != null ? path.asFragment() : null;
+      PathFragment path = lineNumberTable.getPath(getStartOffset());
+      return path;
     }
 
     @Override
diff --git a/src/main/java/com/google/devtools/build/lib/syntax/LineNumberTable.java b/src/main/java/com/google/devtools/build/lib/syntax/LineNumberTable.java
index c006bf9e5e..653abee1f6 100644
--- a/src/main/java/com/google/devtools/build/lib/syntax/LineNumberTable.java
+++ b/src/main/java/com/google/devtools/build/lib/syntax/LineNumberTable.java
@@ -20,7 +20,7 @@ import com.google.devtools.build.lib.concurrent.ThreadSafety.Immutable;
 import com.google.devtools.build.lib.events.Location.LineAndColumn;
 import com.google.devtools.build.lib.util.Pair;
 import com.google.devtools.build.lib.util.StringUtilities;
-import com.google.devtools.build.lib.vfs.Path;
+import com.google.devtools.build.lib.vfs.PathFragment;
 
 import java.io.Serializable;
 import java.util.ArrayList;
@@ -50,9 +50,9 @@ abstract class LineNumberTable implements Serializable {
   /**
    * Returns the path corresponding to the given offset.
    */
-  abstract Path getPath(int offset);
+  abstract PathFragment getPath(int offset);
 
-  static LineNumberTable create(char[] buffer, Path path) {
+  static LineNumberTable create(char[] buffer, PathFragment path) {
     // If #line appears within a BUILD file, we assume it has been preprocessed
     // by gconfig2blaze.  We ignore all actual newlines and compute the logical
     // LNT based only on the presence of #line markers.
@@ -72,10 +72,10 @@ abstract class LineNumberTable implements Serializable {
      * A mapping from line number (line >= 1) to character offset into the file.
      */
     private final int[] linestart;
-    private final Path path;
+    private final PathFragment path;
     private final int bufferLength;
 
-    private Regular(char[] buffer, Path path) {
+    private Regular(char[] buffer, PathFragment path) {
       // Compute the size.
       int size = 2;
       for (int i = 0; i < buffer.length; i++) {
@@ -132,7 +132,7 @@ abstract class LineNumberTable implements Serializable {
     }
 
     @Override
-    Path getPath(int offset) {
+    PathFragment getPath(int offset) {
       return path;
     }
 
@@ -161,9 +161,9 @@ abstract class LineNumberTable implements Serializable {
     private static class SingleHashLine implements Serializable {
       private final int offset;
       private final int line;
-      private final Path path;
+      private final PathFragment path;
 
-      SingleHashLine(int offset, int line, Path path) {
+      SingleHashLine(int offset, int line, PathFragment path) {
         this.offset = offset;
         this.line = line;
         this.path = path;
@@ -181,10 +181,10 @@ abstract class LineNumberTable implements Serializable {
     private static final Pattern pattern = Pattern.compile("\n#line ([0-9]+) \"([^\"\\n]+)\"");
 
     private final List<SingleHashLine> table;
-    private final Path defaultPath;
+    private final PathFragment defaultPath;
     private final int bufferLength;
 
-    private HashLine(char[] buffer, Path defaultPath) {
+    private HashLine(char[] buffer, PathFragment defaultPath) {
       // Not especially efficient, but that's fine: we just exec'd Python.
       String bufString = new String(buffer);
       Matcher m = pattern.matcher(bufString);
@@ -223,7 +223,7 @@ abstract class LineNumberTable implements Serializable {
     }
 
     @Override
-    Path getPath(int offset) {
+    PathFragment getPath(int offset) {
       SingleHashLine hashLine = getHashLine(offset);
       return hashLine == null ? defaultPath : hashLine.path;
     }
diff --git a/src/main/java/com/google/devtools/build/lib/syntax/Parser.java b/src/main/java/com/google/devtools/build/lib/syntax/Parser.java
index 71277a0b4c..8ea20eb7d3 100644
--- a/src/main/java/com/google/devtools/build/lib/syntax/Parser.java
+++ b/src/main/java/com/google/devtools/build/lib/syntax/Parser.java
@@ -31,6 +31,7 @@ import com.google.devtools.build.lib.packages.CachingPackageLocator;
 import com.google.devtools.build.lib.syntax.DictionaryLiteral.DictionaryEntryLiteral;
 import com.google.devtools.build.lib.syntax.IfStatement.ConditionalStatements;
 import com.google.devtools.build.lib.vfs.Path;
+import com.google.devtools.build.lib.vfs.PathFragment;
 
 import java.io.IOException;
 import java.util.ArrayList;
@@ -159,7 +160,7 @@ class Parser {
 
   private CachingPackageLocator locator;
 
-  private List<Path> includedFiles;
+  private List<PathFragment> includedFiles;
 
   private Parser(
       Lexer lexer,
@@ -252,7 +253,7 @@ class Parser {
     return result;
   }
 
-  private void addIncludedFiles(List<Path> files) {
+  private void addIncludedFiles(List<PathFragment> files) {
     this.includedFiles.addAll(files);
   }
 
@@ -622,7 +623,7 @@ class Parser {
       Path path = packagePath.getParentDirectory();
       Path file = path.getRelative(label.getName());
 
-      if (this.includedFiles.contains(file)) {
+      if (this.includedFiles.contains(file.asFragment())) {
         reportError(location, "Recursive inclusion of file '" + path + "'");
         return;
       }
diff --git a/src/main/java/com/google/devtools/build/lib/syntax/ParserInputSource.java b/src/main/java/com/google/devtools/build/lib/syntax/ParserInputSource.java
index e83cec639f..6cfdc94b00 100644
--- a/src/main/java/com/google/devtools/build/lib/syntax/ParserInputSource.java
+++ b/src/main/java/com/google/devtools/build/lib/syntax/ParserInputSource.java
@@ -13,9 +13,9 @@
 // limitations under the License.
 package com.google.devtools.build.lib.syntax;
 
-import com.google.common.hash.HashCode;
 import com.google.devtools.build.lib.vfs.FileSystemUtils;
 import com.google.devtools.build.lib.vfs.Path;
+import com.google.devtools.build.lib.vfs.PathFragment;
 
 import java.io.IOException;
 import java.io.InputStream;
@@ -37,7 +37,7 @@ public abstract class ParserInputSource {
    * Returns the path of the input source. Note: Once constructed, this object
    * will never re-read the content from path.
    */
-  public abstract Path getPath();
+  public abstract PathFragment getPath();
 
   /**
    * Create an input source instance by (eagerly) reading from the file at
@@ -53,7 +53,7 @@ public abstract class ParserInputSource {
       throw new IOException("Unexpected short read from file '" + path
           + "' (expected " + path.getFileSize() + ", got " + content.length + " bytes)");
     }
-    return create(content, path);
+    return create(content, path.asFragment());
   }
 
   /**
@@ -61,7 +61,7 @@ public abstract class ParserInputSource {
    * this source.  Path will be used in error messages etc. but we will *never*
    * attempt to read the content from path.
    */
-  public static ParserInputSource create(String content, Path path) {
+  public static ParserInputSource create(String content, PathFragment path) {
     return create(content.toCharArray(), path);
   }
 
@@ -70,7 +70,7 @@ public abstract class ParserInputSource {
    * this source.  Path will be used in error messages etc. but we will *never*
    * attempt to read the content from path.
    */
-  public static ParserInputSource create(final char[] content, final Path path) {
+  public static ParserInputSource create(final char[] content, final PathFragment path) {
     return new ParserInputSource() {
 
       @Override
@@ -79,7 +79,7 @@ public abstract class ParserInputSource {
       }
 
       @Override
-      public Path getPath() {
+      public PathFragment getPath() {
         return path;
       }
     };
@@ -97,16 +97,9 @@ public abstract class ParserInputSource {
    */
   public static ParserInputSource create(InputStream in, Path path) throws IOException {
     try {
-      return create(new String(FileSystemUtils.readContentAsLatin1(in)), path);
+      return create(new String(FileSystemUtils.readContentAsLatin1(in)), path.asFragment());
     } finally {
       in.close();
     }
   }
-
-  /**
-   * Returns a hash code calculated from the string content of this file.
-   */
-  public String contentHashCode() throws IOException {
-    return HashCode.fromBytes(getPath().getMD5Digest()).toString();
-  }
 }