Move newbranch to standalone package (#9627)

* Move newbranch to standalone package

* move branch functions to modules to avoid dependencies cycles

* fix tests

* fix lint

* fix lint

modules/repository/branch.go

@@ -0,0 +1,163 @@
+// Copyright 2020 The Gitea Authors. All rights reserved.
+// Use of this source code is governed by a MIT-style
+// license that can be found in the LICENSE file.
+
+package repository
+
+import (
+	"fmt"
+
+	"code.gitea.io/gitea/models"
+	"code.gitea.io/gitea/modules/git"
+	"code.gitea.io/gitea/modules/log"
+)
+
+// GetBranch returns a branch by its name
+func GetBranch(repo *models.Repository, branch string) (*git.Branch, error) {
+	gitRepo, err := git.OpenRepository(repo.RepoPath())
+	if err != nil {
+		return nil, err
+	}
+	defer gitRepo.Close()
+
+	return gitRepo.GetBranch(branch)
+}
+
+// GetBranches returns all the branches of a repository
+func GetBranches(repo *models.Repository) ([]*git.Branch, error) {
+	return git.GetBranchesByPath(repo.RepoPath())
+}
+
+// checkBranchName validates branch name with existing repository branches
+func checkBranchName(repo *models.Repository, name string) error {
+	gitRepo, err := git.OpenRepository(repo.RepoPath())
+	if err != nil {
+		return err
+	}
+	defer gitRepo.Close()
+
+	branches, err := GetBranches(repo)
+	if err != nil {
+		return err
+	}
+
+	for _, branch := range branches {
+		if branch.Name == name {
+			return models.ErrBranchAlreadyExists{
+				BranchName: branch.Name,
+			}
+		} else if (len(branch.Name) < len(name) && branch.Name+"/" == name[0:len(branch.Name)+1]) ||
+			(len(branch.Name) > len(name) && name+"/" == branch.Name[0:len(name)+1]) {
+			return models.ErrBranchNameConflict{
+				BranchName: branch.Name,
+			}
+		}
+	}
+
+	if _, err := gitRepo.GetTag(name); err == nil {
+		return models.ErrTagAlreadyExists{
+			TagName: name,
+		}
+	}
+
+	return nil
+}
+
+// CreateNewBranch creates a new repository branch
+func CreateNewBranch(doer *models.User, repo *models.Repository, oldBranchName, branchName string) (err error) {
+	// Check if branch name can be used
+	if err := checkBranchName(repo, branchName); err != nil {
+		return err
+	}
+
+	if !git.IsBranchExist(repo.RepoPath(), oldBranchName) {
+		return fmt.Errorf("OldBranch: %s does not exist. Cannot create new branch from this", oldBranchName)
+	}
+
+	basePath, err := models.CreateTemporaryPath("branch-maker")
+	if err != nil {
+		return err
+	}
+	defer func() {
+		if err := models.RemoveTemporaryPath(basePath); err != nil {
+			log.Error("CreateNewBranch: RemoveTemporaryPath: %s", err)
+		}
+	}()
+
+	if err := git.Clone(repo.RepoPath(), basePath, git.CloneRepoOptions{
+		Bare:   true,
+		Shared: true,
+	}); err != nil {
+		log.Error("Failed to clone repository: %s (%v)", repo.FullName(), err)
+		return fmt.Errorf("Failed to clone repository: %s (%v)", repo.FullName(), err)
+	}
+
+	gitRepo, err := git.OpenRepository(basePath)
+	if err != nil {
+		log.Error("Unable to open temporary repository: %s (%v)", basePath, err)
+		return fmt.Errorf("Failed to open new temporary repository in: %s %v", basePath, err)
+	}
+	defer gitRepo.Close()
+
+	if err = gitRepo.CreateBranch(branchName, oldBranchName); err != nil {
+		log.Error("Unable to create branch: %s from %s. (%v)", branchName, oldBranchName, err)
+		return fmt.Errorf("Unable to create branch: %s from %s. (%v)", branchName, oldBranchName, err)
+	}
+
+	if err = git.Push(basePath, git.PushOptions{
+		Remote: "origin",
+		Branch: branchName,
+		Env:    models.PushingEnvironment(doer, repo),
+	}); err != nil {
+		return fmt.Errorf("Push: %v", err)
+	}
+
+	return nil
+}
+
+// CreateNewBranchFromCommit creates a new repository branch
+func CreateNewBranchFromCommit(doer *models.User, repo *models.Repository, commit, branchName string) (err error) {
+	// Check if branch name can be used
+	if err := checkBranchName(repo, branchName); err != nil {
+		return err
+	}
+	basePath, err := models.CreateTemporaryPath("branch-maker")
+	if err != nil {
+		return err
+	}
+	defer func() {
+		if err := models.RemoveTemporaryPath(basePath); err != nil {
+			log.Error("CreateNewBranchFromCommit: RemoveTemporaryPath: %s", err)
+		}
+	}()
+
+	if err := git.Clone(repo.RepoPath(), basePath, git.CloneRepoOptions{
+		Bare:   true,
+		Shared: true,
+	}); err != nil {
+		log.Error("Failed to clone repository: %s (%v)", repo.FullName(), err)
+		return fmt.Errorf("Failed to clone repository: %s (%v)", repo.FullName(), err)
+	}
+
+	gitRepo, err := git.OpenRepository(basePath)
+	if err != nil {
+		log.Error("Unable to open temporary repository: %s (%v)", basePath, err)
+		return fmt.Errorf("Failed to open new temporary repository in: %s %v", basePath, err)
+	}
+	defer gitRepo.Close()
+
+	if err = gitRepo.CreateBranch(branchName, commit); err != nil {
+		log.Error("Unable to create branch: %s from %s. (%v)", branchName, commit, err)
+		return fmt.Errorf("Unable to create branch: %s from %s. (%v)", branchName, commit, err)
+	}
+
+	if err = git.Push(basePath, git.PushOptions{
+		Remote: "origin",
+		Branch: branchName,
+		Env:    models.PushingEnvironment(doer, repo),
+	}); err != nil {
+		return fmt.Errorf("Push: %v", err)
+	}
+
+	return nil
+}