vikunja-api/vendor/golang.org/x/tools/go/packages/external.go

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2019-02-18 20:32:41 +01:00
// Copyright 2018 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
// This file enables an external tool to intercept package requests.
// If the tool is present then its results are used in preference to
// the go list command.
package packages
import (
"bytes"
"encoding/json"
"fmt"
"os/exec"
"strings"
)
// findExternalTool returns the file path of a tool that supplies
// the build system package structure, or "" if not found."
// If GOPACKAGESDRIVER is set in the environment findExternalTool returns its
// value, otherwise it searches for a binary named gopackagesdriver on the PATH.
func findExternalDriver(cfg *Config) driver {
const toolPrefix = "GOPACKAGESDRIVER="
tool := ""
for _, env := range cfg.Env {
if val := strings.TrimPrefix(env, toolPrefix); val != env {
tool = val
}
}
if tool != "" && tool == "off" {
return nil
}
if tool == "" {
var err error
tool, err = exec.LookPath("gopackagesdriver")
if err != nil {
return nil
}
}
return func(cfg *Config, words ...string) (*driverResponse, error) {
buf := new(bytes.Buffer)
fullargs := []string{
"list",
fmt.Sprintf("-test=%t", cfg.Tests),
fmt.Sprintf("-export=%t", usesExportData(cfg)),
fmt.Sprintf("-deps=%t", cfg.Mode >= LoadImports),
}
for _, f := range cfg.BuildFlags {
fullargs = append(fullargs, fmt.Sprintf("-buildflag=%v", f))
}
fullargs = append(fullargs, "--")
fullargs = append(fullargs, words...)
cmd := exec.CommandContext(cfg.Context, tool, fullargs...)
cmd.Env = cfg.Env
cmd.Dir = cfg.Dir
cmd.Stdout = buf
cmd.Stderr = new(bytes.Buffer)
if err := cmd.Run(); err != nil {
return nil, fmt.Errorf("%v: %v: %s", tool, err, cmd.Stderr)
}
var response driverResponse
if err := json.Unmarshal(buf.Bytes(), &response); err != nil {
return nil, err
}
return &response, nil
}
}