// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

// Package codehost defines the interface implemented by a code hosting source,
// along with support code for use by implementations.
package codehost

import (
	"bytes"
	"context"
	"crypto/sha256"
	"fmt"
	"io"
	"io/fs"
	"os"
	"os/exec"
	"path/filepath"
	"strings"
	"sync"

	"cmd/go/internal/gover"
	"cmd/go/internal/modfetch/codehost"

	"golang.org/x/mod/modfile"
	"golang.org/x/mod/module"
	"golang.org/x/mod/semver"
	modzip "golang.org/x/mod/zip"
)

// A codeRepo implements modfetch.Repo using an underlying codehost.Repo.
type codeRepo struct {
	modPath string

	// code is the repository containing this module.
	code codehost.Repo
	// codeRoot is the import path at the root of code.

	if err != nil {
		return nil, err
	}
	return newCodeRepo(code, rr.Root, path)
}

func lookupCodeRepo(ctx context.Context, rr *vcs.RepoRoot) (codehost.Repo, error) {
	code, err := codehost.NewRepo(ctx, rr.VCS.Cmd, rr.Repo)
	if err != nil {
		if _, ok := err.(*codehost.VCSError); ok {
			return nil, err
		}
		return nil, fmt.Errorf("lookup %s: %v", rr.Root, err)
	}
	return code, nil
}

	"errors"
	"fmt"
	"io"
	"io/fs"
	"net/url"
	"path"
	pathpkg "path"
	"path/filepath"
	"strings"
	"sync"
	"time"

	"cmd/go/internal/base"
	"cmd/go/internal/cfg"
	"cmd/go/internal/modfetch/codehost"
	"cmd/go/internal/web"

	"golang.org/x/mod/module"
	"golang.org/x/mod/semver"
)

var HelpGoproxy = &base.Command{
	UsageLine: "goproxy",
	Short:     "module proxy protocol",
	Long: `

			}
		})
	}
}

// fixedTagsRepo is a fake codehost.Repo that returns a fixed list of tags
type fixedTagsRepo struct {
	tags []string
	codehost.Repo
}

func (ch *fixedTagsRepo) Tags(ctx context.Context, prefix string) (*codehost.Tags, error) {
	tags := &codehost.Tags{}
	for _, t := range ch.tags {
		tags.List = append(tags.List, codehost.Tag{Name: t})
	}
	return tags, nil
}

// returning either a new origin or one of its unmodified arguments.
// If the two origins conflict including if either is nil,
// mergeOrigin returns nil.
func mergeOrigin(m1, m2 *codehost.Origin) *codehost.Origin {
	if m1 == nil || m2 == nil {
		return nil
	}

	if m2.VCS != m1.VCS ||
		m2.URL != m1.URL ||
		m2.Subdir != m1.Subdir {
		return nil
	}

	merged := *m1

func checkReuse(ctx context.Context, m module.Version, old *codehost.Origin) error {
	return modfetch.TryProxies(func(proxy string) error {
		repo, err := lookupRepo(ctx, proxy, m.Path)
		if err != nil {
			return err
		}
		return checkReuseRepo(ctx, repo, m.Path, m.Version, old)
	})
}

func checkReuseRepo(ctx context.Context, repo versionRepo, path, query string, origin *codehost.Origin) error {
	if origin == nil {

	"errors"
	"flag"
	"fmt"
	"internal/txtar"
	"io"
	"io/fs"
	"log"
	"net"
	"net/http"
	"os"
	"path/filepath"
	"strconv"
	"strings"
	"sync"
	"testing"

	"cmd/go/internal/modfetch/codehost"
	"cmd/go/internal/par"

	"golang.org/x/mod/module"
	"golang.org/x/mod/semver"
	"golang.org/x/mod/sumdb"
	"golang.org/x/mod/sumdb/dirhash"
)

var (

import (
	"context"
	"encoding/json"
	"errors"
	"os"
	"runtime"
	"sync"

	"cmd/go/internal/base"
	"cmd/go/internal/cfg"
	"cmd/go/internal/gover"
	"cmd/go/internal/modfetch"
	"cmd/go/internal/modfetch/codehost"
	"cmd/go/internal/modload"
	"cmd/go/internal/toolchain"

	"golang.org/x/mod/module"
)

var cmdDownload = &base.Command{
	UsageLine: "go mod download [-x] [-json] [-reuse=old.json] [modules]",

	"math/rand"
	"os"
	"path/filepath"
	"strconv"
	"strings"
	"sync"

	"cmd/go/internal/base"
	"cmd/go/internal/cfg"
	"cmd/go/internal/gover"
	"cmd/go/internal/lockedfile"
	"cmd/go/internal/modfetch/codehost"
	"cmd/go/internal/par"
	"cmd/go/internal/robustio"
	"cmd/internal/telemetry"

	"golang.org/x/mod/module"
	"golang.org/x/mod/semver"
)

func cacheDir(ctx context.Context, path string) (string, error) {