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, 16 insertions, 18 deletions

diff --git a/src/main/java/com/google/devtools/build/lib/rules/cpp/CcCompilationHelper.java b/src/main/java/com/google/devtools/build/lib/rules/cpp/CcCompilationHelper.java
index d6464d1340..a7c1615d92 100644
--- a/src/main/java/com/google/devtools/build/lib/rules/cpp/CcCompilationHelper.java
+++ b/src/main/java/com/google/devtools/build/lib/rules/cpp/CcCompilationHelper.java
@@ -757,15 +757,25 @@ public final class CcCompilationHelper {
           null);
     }
 
-    PathFragment prefix =
-        ruleContext.attributes().isAttributeValueExplicitlySpecified("include_prefix")
-            ? PathFragment.create(ruleContext.attributes().get("include_prefix", Type.STRING))
-            : null;
+    PathFragment prefix = null;
+    if (ruleContext.attributes().isAttributeValueExplicitlySpecified("include_prefix")) {
+      String prefixAttr = ruleContext.attributes().get("include_prefix", Type.STRING);
+      prefix = PathFragment.create(prefixAttr);
+      if (PathFragment.containsUplevelReferences(prefixAttr)) {
+        ruleContext.attributeError("include_prefix", "should not contain uplevel references");
+      }
+      if (prefix.isAbsolute()) {
+        ruleContext.attributeError("include_prefix", "should be a relative path");
+      }
+    }
 
     PathFragment stripPrefix;
     if (ruleContext.attributes().isAttributeValueExplicitlySpecified("strip_include_prefix")) {
-      stripPrefix =
-          PathFragment.create(ruleContext.attributes().get("strip_include_prefix", Type.STRING));
+      String stripPrefixAttr = ruleContext.attributes().get("strip_include_prefix", Type.STRING);
+      if (PathFragment.containsUplevelReferences(stripPrefixAttr)) {
+        ruleContext.attributeError("strip_include_prefix", "should not contain uplevel references");
+      }
+      stripPrefix = PathFragment.create(stripPrefixAttr);
       if (stripPrefix.isAbsolute()) {
         stripPrefix =
             ruleContext
@@ -791,18 +801,6 @@ public final class CcCompilationHelper {
           null);
     }
 
-    if (stripPrefix.containsUplevelReferences()) {
-      ruleContext.attributeError("strip_include_prefix", "should not contain uplevel references");
-    }
-
-    if (prefix != null && prefix.containsUplevelReferences()) {
-      ruleContext.attributeError("include_prefix", "should not contain uplevel references");
-    }
-
-    if (prefix != null && prefix.isAbsolute()) {
-      ruleContext.attributeError("include_prefix", "should be a relative path");
-    }
-
     if (ruleContext.hasErrors()) {
       return new PublicHeaders(ImmutableList.<Artifact>of(), ImmutableList.<Artifact>of(), null);
     }