Introduce infrastructure for calling and testing nested

commands, error messages and exit codes.

Also:
- implements the -Xclang-path= flag as use case of calling
  a nested command.
- adds tests for forwarding errors, comparing against the
  old wrapper, and exit codes.
- captures the source locations of errors in error messages.
- compares exit codes of new wrapper and old wrapper.

BUG=chromium:773875
TEST=unit test

Change-Id: I919e58091d093d68939809f676f799a68ec7a34e
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/third_party/toolchain-utils/+/1676833
Reviewed-by: George Burgess <gbiv@chromium.org>
Tested-by: Tobias Bosch <tbosch@google.com>

1 files changed, 63 insertions, 1 deletions

diff --git a/compiler_wrapper/env.go b/compiler_wrapper/env.go
index 3c106d4a..6cf1a1b9 100644
--- a/compiler_wrapper/env.go
+++ b/compiler_wrapper/env.go
@@ -1,13 +1,20 @@
 package main
 
 import (
+	"bytes"
+	"io"
 	"os"
+	"syscall"
 )
 
 type env interface {
 	getenv(key string) string
 	environ() []string
 	getwd() string
+	stdout() io.Writer
+	stderr() io.Writer
+	run(cmd *command, stdout io.Writer, stderr io.Writer) error
+	exec(cmd *command) error
 }
 
 type processEnv struct {
@@ -17,7 +24,7 @@ type processEnv struct {
 func newProcessEnv() (env, error) {
 	wd, err := os.Getwd()
 	if err != nil {
-		return nil, err
+		return nil, wrapErrorwithSourceLocf(err, "failed to read working directory")
 	}
 	return &processEnv{wd: wd}, nil
 }
@@ -35,3 +42,58 @@ func (env *processEnv) environ() []string {
 func (env *processEnv) getwd() string {
 	return env.wd
 }
+
+func (env *processEnv) stdout() io.Writer {
+	return os.Stdout
+}
+
+func (env *processEnv) stderr() io.Writer {
+	return os.Stderr
+}
+
+func (env *processEnv) exec(cmd *command) error {
+	execCmd := newExecCmd(env, cmd)
+	return syscall.Exec(execCmd.Path, execCmd.Args, execCmd.Env)
+}
+
+func (env *processEnv) run(cmd *command, stdout io.Writer, stderr io.Writer) error {
+	execCmd := newExecCmd(env, cmd)
+	execCmd.Stdout = stdout
+	execCmd.Stderr = stderr
+	return execCmd.Run()
+}
+
+type commandRecordingEnv struct {
+	env
+	cmdResults []*commandResult
+}
+type commandResult struct {
+	cmd      *command
+	stdout   string
+	stderr   string
+	exitCode int
+}
+
+var _ env = (*commandRecordingEnv)(nil)
+
+func (env *commandRecordingEnv) exec(cmd *command) error {
+	// Note: We will only get here if the exec failed,
+	// e.g. when the underlying command could not be called.
+	// In this case, we don't compare commands, so nothing to record.
+	return env.exec(cmd)
+}
+
+func (env *commandRecordingEnv) run(cmd *command, stdout io.Writer, stderr io.Writer) error {
+	stdoutBuffer := &bytes.Buffer{}
+	stderrBuffer := &bytes.Buffer{}
+	err := env.env.run(cmd, io.MultiWriter(stdout, stdoutBuffer), io.MultiWriter(stderr, stderrBuffer))
+	if exitCode, ok := getExitCode(err); ok {
+		env.cmdResults = append(env.cmdResults, &commandResult{
+			cmd:      cmd,
+			stdout:   stdoutBuffer.String(),
+			stderr:   stderrBuffer.String(),
+			exitCode: exitCode,
+		})
+	}
+	return err
+}