1 files changed, 141 insertions, 0 deletions
diff --git a/core/command/pull.go b/core/command/pull.go
new file mode 100644
index 0000000..5644417
--- /dev/null
+++ b/core/command/pull.go
@@ -0,0 +1,141 @@
+package command
+
+import (
+	"os"
+	"strings"
+
+	gerr "github.com/isacikgoz/gitbatch/core/errors"
+	"github.com/isacikgoz/gitbatch/core/git"
+	log "github.com/sirupsen/logrus"
+	gogit "gopkg.in/src-d/go-git.v4"
+	"gopkg.in/src-d/go-git.v4/plumbing"
+	"gopkg.in/src-d/go-git.v4/plumbing/transport"
+	"gopkg.in/src-d/go-git.v4/plumbing/transport/http"
+	"gopkg.in/src-d/go-git.v4/storage/memory"
+)
+
+var (
+	pullCmdMode  string
+	pullTryCount int
+
+	pullCommand       = "pull"
+	pullCmdModeLegacy = "git"
+	pullCmdModeNative = "go-git"
+	pullMaxTry        = 1
+)
+
+// PullOptions defines the rules for pull operation
+type PullOptions struct {
+	// Name of the remote to fetch from. Defaults to origin.
+	RemoteName string
+	// ReferenceName Remote branch to clone. If empty, uses HEAD.
+	ReferenceName string
+	// Fetch only ReferenceName if true.
+	SingleBranch bool
+	// Credentials holds the user and pswd information
+	Credentials git.Credentials
+	// Process logs the output to stdout
+	Progress bool
+	// Force allows the pull to update a local branch even when the remote
+	// branch does not descend from it.
+	Force bool
+}
+
+// Pull ncorporates changes from a remote repository into the current branch.
+func Pull(r *git.Repository, options PullOptions) (err error) {
+	// here we configure pull operation
+	// default mode is go-git (this may be configured)
+	pullCmdMode = pullCmdModeNative
+	pullTryCount = 0
+
+	switch pullCmdMode {
+	case pullCmdModeLegacy:
+		err = pullWithGit(r, options)
+		return err
+	case pullCmdModeNative:
+		err = pullWithGoGit(r, options)
+		return err
+	}
+	return nil
+}
+
+func pullWithGit(r *git.Repository, options PullOptions) (err error) {
+	args := make([]string, 0)
+	args = append(args, pullCommand)
+	// parse options to command line arguments
+	if len(options.RemoteName) > 0 {
+		args = append(args, options.RemoteName)
+	}
+	if options.Force {
+		args = append(args, "-f")
+	}
+	if out, err := GenericGitCommandWithOutput(r.AbsPath, args); err != nil {
+		return gerr.ParseGitError(out, err)
+	}
+	r.SetWorkStatus(git.Success)
+	return r.Refresh()
+}
+
+func pullWithGoGit(r *git.Repository, options PullOptions) (err error) {
+	opt := &gogit.PullOptions{
+		RemoteName:   options.RemoteName,
+		SingleBranch: options.SingleBranch,
+		Force:        options.Force,
+	}
+	if len(options.ReferenceName) > 0 {
+		ref := plumbing.NewRemoteReferenceName(options.RemoteName, options.ReferenceName)
+		opt.ReferenceName = ref
+	}
+	// if any credential is given, let's add it to the git.PullOptions
+	if len(options.Credentials.User) > 0 {
+		protocol, err := git.AuthProtocol(r.State.Remote)
+		if err != nil {
+			return err
+		}
+		if protocol == git.AuthProtocolHTTP || protocol == git.AuthProtocolHTTPS {
+			opt.Auth = &http.BasicAuth{
+				Username: options.Credentials.User,
+				Password: options.Credentials.Password,
+			}
+		} else {
+			return gerr.ErrInvalidAuthMethod
+		}
+	}
+	if options.Progress {
+		opt.Progress = os.Stdout
+	}
+	w, err := r.Repo.Worktree()
+	if err != nil {
+		return err
+	}
+
+	if err = w.Pull(opt); err != nil {
+		if err == gogit.NoErrAlreadyUpToDate {
+			// log.Error("error: " + err.Error())
+			// Already up-to-date
+			log.Warn(err.Error())
+			// TODO: submit a PR for this kind of error, this type of catch is lame
+		} else if err == memory.ErrRefHasChanged && pullTryCount < pullMaxTry {
+			pullTryCount++
+			log.Error("trying to fetch")
+			if err := Fetch(r, FetchOptions{
+				RemoteName: options.RemoteName,
+			}); err != nil {
+				return err
+			}
+			return Pull(r, options)
+		} else if strings.Contains(err.Error(), "SSH_AUTH_SOCK") {
+			// The env variable SSH_AUTH_SOCK is not defined, maybe git can handle this
+			return pullWithGit(r, options)
+		} else if err == transport.ErrAuthenticationRequired {
+			log.Warn(err.Error())
+			return gerr.ErrAuthenticationRequired
+		} else {
+			log.Warn(err.Error())
+			return pullWithGit(r, options)
+		}
+	}
+
+	r.SetWorkStatus(git.Success)
+	return r.Refresh()
+}