Extract actions on new pull request from models to pulls service and move code.gitea.io/gitea/modules/pull to code.gitea.io/gitea/services/pull (#8218)

* extract actions on new pull request from models to pulls service

* improve code

* move code.gitea.io/gitea/modules/pull to code.gitea.io/gitea/services/pull

* fix fmt

* Rename pulls.go to pull.go

services/pull/commit_status.go

@@ -0,0 +1,70 @@
+// Copyright 2019 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 pull
+
+import (
+	"code.gitea.io/gitea/models"
+	"code.gitea.io/gitea/modules/git"
+
+	"github.com/pkg/errors"
+)
+
+// IsCommitStatusContextSuccess returns true if all required status check contexts succeed.
+func IsCommitStatusContextSuccess(commitStatuses []*models.CommitStatus, requiredContexts []string) bool {
+	for _, ctx := range requiredContexts {
+		var found bool
+		for _, commitStatus := range commitStatuses {
+			if commitStatus.Context == ctx {
+				if commitStatus.State != models.CommitStatusSuccess {
+					return false
+				}
+
+				found = true
+				break
+			}
+		}
+		if !found {
+			return false
+		}
+	}
+	return true
+}
+
+// IsPullCommitStatusPass returns if all required status checks PASS
+func IsPullCommitStatusPass(pr *models.PullRequest) (bool, error) {
+	if err := pr.LoadProtectedBranch(); err != nil {
+		return false, errors.Wrap(err, "GetLatestCommitStatus")
+	}
+	if pr.ProtectedBranch == nil || !pr.ProtectedBranch.EnableStatusCheck {
+		return true, nil
+	}
+
+	// check if all required status checks are successful
+	headGitRepo, err := git.OpenRepository(pr.HeadRepo.RepoPath())
+	if err != nil {
+		return false, errors.Wrap(err, "OpenRepository")
+	}
+
+	if !headGitRepo.IsBranchExist(pr.HeadBranch) {
+		return false, errors.New("Head branch does not exist, can not merge")
+	}
+
+	sha, err := headGitRepo.GetBranchCommitID(pr.HeadBranch)
+	if err != nil {
+		return false, errors.Wrap(err, "GetBranchCommitID")
+	}
+
+	if err := pr.LoadBaseRepo(); err != nil {
+		return false, errors.Wrap(err, "LoadBaseRepo")
+	}
+
+	commitStatuses, err := models.GetLatestCommitStatus(pr.BaseRepo, sha, 0)
+	if err != nil {
+		return false, errors.Wrap(err, "GetLatestCommitStatus")
+	}
+
+	return IsCommitStatusContextSuccess(commitStatuses, pr.ProtectedBranch.StatusCheckContexts), nil
+}