Replace path implementation.

Path and PathFragment have been replaced with String-based implementations. They are pretty similar, but each method is dissimilar enough that I did not feel sharing code was appropriate.

A summary of changes:

PATH
====

* Subsumes LocalPath (deleted, its tests repurposed)
* Use a simple string to back Path
* Path instances are no longer interned; Reference equality will no longer work
* Always normalized (same as before)
* Some operations will now be slower, like instance compares (which were previously just a reference check)
* Multiple identical paths will now consume more memory since they are not interned

PATH FRAGMENT
=============

* Use a simple string to back PathFragment
* No more segment arrays with interned strings
* Always normalized
* Remove isNormalized
* Replace some isNormalizied uses with containsUpLevelReferences() to check if path fragments try to escape their scope
* To check if user input is normalized, supply static methods on PathFragment to validate the string before constructing a PathFragment
* Because PathFragments are always normalized, we have to replace checks for literal "." from PathFragment#getPathString to PathFragment#getSafePathString. The latter returns "." for the empty string.
* The previous implementation supported efficient segment semantics (segment count, iterating over segments). This is now expensive since we do longer have a segment array.

ARTIFACT
========

* Remove Path instance. It is instead dynamically constructed on request. This is necessary to avoid this CL becoming a memory regression.

RELNOTES: None
PiperOrigin-RevId: 185062932

1 files changed, 37 insertions, 1 deletions

diff --git a/src/main/java/com/google/devtools/build/lib/buildeventstream/transports/BuildEventTransportFactory.java b/src/main/java/com/google/devtools/build/lib/buildeventstream/transports/BuildEventTransportFactory.java
index d07f6a59ea..8c3921521e 100644
--- a/src/main/java/com/google/devtools/build/lib/buildeventstream/transports/BuildEventTransportFactory.java
+++ b/src/main/java/com/google/devtools/build/lib/buildeventstream/transports/BuildEventTransportFactory.java
@@ -22,6 +22,8 @@ import com.google.devtools.build.lib.buildeventstream.BuildEventTransport;
 import com.google.devtools.build.lib.buildeventstream.PathConverter;
 import com.google.devtools.build.lib.vfs.Path;
 import java.io.IOException;
+import java.net.URI;
+import java.net.URISyntaxException;
 
 /** Factory used to create a Set of BuildEventTransports from BuildEventStreamOptions. */
 public enum BuildEventTransportFactory {
@@ -101,7 +103,41 @@ public enum BuildEventTransportFactory {
   private static class NullPathConverter implements PathConverter {
     @Override
     public String apply(Path path) {
-      return path.toURI().toString();
+      return pathToUriString(path.getPathString());
+    }
+  }
+
+  /**
+   * Returns the path encoded as an {@link URI}.
+   *
+   * <p>This concrete implementation returns URIs with "file" as the scheme. For Example: - On Unix
+   * the path "/tmp/foo bar.txt" will be encoded as "file:///tmp/foo%20bar.txt". - On Windows the
+   * path "C:\Temp\Foo Bar.txt" will be encoded as "file:///C:/Temp/Foo%20Bar.txt"
+   *
+   * <p>Implementors extending this class for special filesystems will likely need to override this
+   * method.
+   *
+   * @throws URISyntaxException if the URI cannot be constructed.
+   */
+  static String pathToUriString(String path) {
+    if (!path.startsWith("/")) {
+      // On Windows URI's need to start with a '/'. i.e. C:\Foo\Bar would be file:///C:/Foo/Bar
+      path = "/" + path;
+    }
+    try {
+      return new URI(
+              "file",
+              // Needs to be "" instead of null, so that toString() will append "//" after the
+              // scheme.
+              // We need this for backwards compatibility reasons as some consumers of the BEP are
+              // broken.
+              "",
+              path,
+              null,
+              null)
+          .toString();
+    } catch (URISyntaxException e) {
+      throw new IllegalStateException(e);
     }
   }
 }