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, 1 insertions, 3 deletions

diff --git a/src/main/java/com/google/devtools/build/lib/windows/WindowsSubprocessFactory.java b/src/main/java/com/google/devtools/build/lib/windows/WindowsSubprocessFactory.java
index a69884066c..af591cc7e8 100644
--- a/src/main/java/com/google/devtools/build/lib/windows/WindowsSubprocessFactory.java
+++ b/src/main/java/com/google/devtools/build/lib/windows/WindowsSubprocessFactory.java
@@ -83,9 +83,7 @@ public class WindowsSubprocessFactory implements SubprocessFactory {
     // If it's not absolute, then it cannot be longer than MAX_PATH, since MAX_PATH also limits the
     // length of file names.
     PathFragment argv0fragment = PathFragment.create(argv0);
-    return (argv0fragment.isAbsolute())
-        ? argv0fragment.normalize().getPathString().replace('/', '\\')
-        : argv0;
+    return (argv0fragment.isAbsolute()) ? argv0fragment.getPathString().replace('/', '\\') : argv0;
   }
 
   private String getRedirectPath(StreamAction action, File file) {