Rewrite AbstractSandboxSpawnRunner to use Subprocess

It was previously using Command. This change is in preparation for
merging the local sandboxed and non-sandboxed execution paths, in order
to simplify supporting async execution for both.

I copied over the equivalent code (with minor changes) from
LocalSpawnRunner with the intent of unifying the LocalSpawnRunner and
the AbstractSandboxSpawnRunner. It may be possible to extract this into
a common class rather than having two copies. TBD.

PiperOrigin-RevId: 262545190

src/main/java/com/google/devtools/build/lib/sandbox/AbstractSandboxSpawnRunner.java

@@ -32,14 +32,13 @@
 import com.google.devtools.build.lib.exec.SpawnRunner;
 import com.google.devtools.build.lib.exec.TreeDeleter;
 import com.google.devtools.build.lib.runtime.CommandEnvironment;
-import com.google.devtools.build.lib.shell.AbnormalTerminationException;
-import com.google.devtools.build.lib.shell.Command;
-import com.google.devtools.build.lib.shell.CommandException;
-import com.google.devtools.build.lib.shell.CommandResult;
 import com.google.devtools.build.lib.shell.ExecutionStatistics;
+import com.google.devtools.build.lib.shell.Subprocess;
+import com.google.devtools.build.lib.shell.SubprocessBuilder;
+import com.google.devtools.build.lib.shell.TerminationStatus;
 import com.google.devtools.build.lib.util.CommandFailureUtils;
 import com.google.devtools.build.lib.util.OS;
-import com.google.devtools.build.lib.util.io.OutErr;
+import com.google.devtools.build.lib.util.io.FileOutErr;
 import com.google.devtools.build.lib.vfs.FileSystem;
 import com.google.devtools.build.lib.vfs.Path;
 import java.io.IOException;
@@ -104,7 +103,7 @@ protected SpawnResult runSpawn(
       throws IOException, InterruptedException {
     try {
       sandbox.createFileSystem();
-      OutErr outErr = context.getFileOutErr();
+      FileOutErr outErr = context.getFileOutErr();
       context.prefetchInputs();
 
       SpawnResult result = run(originalSpawn, sandbox, outErr, timeout, statisticsPath);
@@ -127,14 +126,10 @@ protected SpawnResult runSpawn(
   private final SpawnResult run(
       Spawn originalSpawn,
       SandboxedSpawn sandbox,
-      OutErr outErr,
+      FileOutErr outErr,
       Duration timeout,
       Path statisticsPath)
       throws IOException, InterruptedException {
-    Command cmd = new Command(
-        sandbox.getArguments().toArray(new String[0]),
-        sandbox.getEnvironment(),
-        sandbox.getSandboxExecRoot().getPathFile());
     String failureMessage;
     if (sandboxOptions.sandboxDebug) {
       failureMessage =
@@ -155,23 +150,29 @@ private final SpawnResult run(
               + SANDBOX_DEBUG_SUGGESTION;
     }
 
+    SubprocessBuilder subprocessBuilder = new SubprocessBuilder();
+    subprocessBuilder.setWorkingDirectory(sandbox.getSandboxExecRoot().getPathFile());
+    subprocessBuilder.setStdout(outErr.getOutputPath().getPathFile());
+    subprocessBuilder.setStderr(outErr.getErrorPath().getPathFile());
+    subprocessBuilder.setEnv(sandbox.getEnvironment());
+    subprocessBuilder.setArgv(sandbox.getArguments());
     long startTime = System.currentTimeMillis();
-    CommandResult commandResult;
+    TerminationStatus terminationStatus;
     try {
-      commandResult = cmd.execute(outErr.getOutputStream(), outErr.getErrorStream());
-      if (Thread.currentThread().isInterrupted()) {
-        throw new InterruptedException();
-      }
-    } catch (AbnormalTerminationException e) {
-      if (Thread.currentThread().isInterrupted()) {
-        throw new InterruptedException();
+      Subprocess subprocess = subprocessBuilder.start();
+      subprocess.getOutputStream().close();
+      try {
+        subprocess.waitFor();
+        terminationStatus = new TerminationStatus(subprocess.exitValue(), subprocess.timedout());
+      } catch (InterruptedException e) {
+        subprocess.destroy();
+        throw e;
       }
-      commandResult = e.getResult();
-    } catch (CommandException e) {
-      // At the time this comment was written, this must be a ExecFailedException encapsulating an
-      // IOException from the underlying Subprocess.Factory.
+    } catch (IOException e) {
       String msg = e.getMessage() == null ? e.getClass().getName() : e.getMessage();
-      outErr.getErrorStream().write(("Action failed to execute: " + msg + "\n").getBytes(UTF_8));
+      outErr
+          .getErrorStream()
+          .write(("Action failed to execute: java.io.IOException: " + msg + "\n").getBytes(UTF_8));
       outErr.getErrorStream().flush();
       return new SpawnResult.Builder()
           .setRunnerName(getName())
@@ -183,11 +184,8 @@ private final SpawnResult run(
 
     // TODO(b/62588075): Calculate wall time inside commands instead?
     Duration wallTime = Duration.ofMillis(System.currentTimeMillis() - startTime);
-    boolean wasTimeout = wasTimeout(timeout, wallTime);
-    int exitCode =
-        wasTimeout
-            ? POSIX_TIMEOUT_EXIT_CODE
-            : commandResult.getTerminationStatus().getRawExitCode();
+    boolean wasTimeout = terminationStatus.timedOut() || wasTimeout(timeout, wallTime);
+    int exitCode = wasTimeout ? POSIX_TIMEOUT_EXIT_CODE : terminationStatus.getRawExitCode();
     Status status =
         wasTimeout
             ? Status.TIMEOUT