Add repository_ctx.which(str): returns the path of a command

This methods mimick the behavior of the `which` utility.

Issue #893: Step 4 of http://goo.gl/OZV3o0. See http://goo.gl/fD4ZsY.

--
MOS_MIGRATED_REVID=115050970

1 files changed, 19 insertions, 0 deletions

diff --git a/src/test/java/com/google/devtools/build/lib/bazel/repository/skylark/SkylarkRepositoryContextTest.java b/src/test/java/com/google/devtools/build/lib/bazel/repository/skylark/SkylarkRepositoryContextTest.java
index 2e782ef1cc..9d49587aca 100644
--- a/src/test/java/com/google/devtools/build/lib/bazel/repository/skylark/SkylarkRepositoryContextTest.java
+++ b/src/test/java/com/google/devtools/build/lib/bazel/repository/skylark/SkylarkRepositoryContextTest.java
@@ -28,6 +28,7 @@ import com.google.devtools.build.lib.syntax.Argument.Passed;
 import com.google.devtools.build.lib.syntax.BuiltinFunction;
 import com.google.devtools.build.lib.syntax.FuncallExpression;
 import com.google.devtools.build.lib.syntax.Identifier;
+import com.google.devtools.build.lib.syntax.Runtime;
 import com.google.devtools.build.lib.syntax.Type;
 import com.google.devtools.build.lib.testutil.Scratch;
 import com.google.devtools.build.lib.vfs.Path;
@@ -96,4 +97,22 @@ public class SkylarkRepositoryContextTest {
     assertThat(context.getAttr().getKeys()).contains("foo");
     assertThat(context.getAttr().getValue("foo")).isEqualTo("bar");
   }
+
+  @Test
+  public void testWhich() throws Exception {
+    setUpContexForRule("test");
+    SkylarkRepositoryContext.setPathEnvironment("/bin", "/path/sbin", ".");
+    scratch.file("/bin/true").setExecutable(true);
+    scratch.file("/path/sbin/true").setExecutable(true);
+    scratch.file("/path/sbin/false").setExecutable(true);
+    scratch.file("/path/bin/undef").setExecutable(true);
+    scratch.file("/path/bin/def").setExecutable(true);
+    scratch.file("/bin/undef");
+
+    assertThat(context.which("anything")).isEqualTo(Runtime.NONE);
+    assertThat(context.which("def")).isEqualTo(Runtime.NONE);
+    assertThat(context.which("undef")).isEqualTo(Runtime.NONE);
+    assertThat(context.which("true").toString()).isEqualTo("/bin/true");
+    assertThat(context.which("false").toString()).isEqualTo("/path/sbin/false");
+  }
 }