Merge branch 'main' into lunny/some_refactors

services/git/compare.go

@@ -0,0 +1,88 @@
+// Copyright 2025 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package git
+
+import (
+	"context"
+	"fmt"
+
+	repo_model "code.gitea.io/gitea/models/repo"
+	"code.gitea.io/gitea/modules/git"
+	"code.gitea.io/gitea/modules/gitrepo"
+)
+
+// CompareInfo represents needed information for comparing references.
+type CompareInfo struct {
+	BaseRepo         *repo_model.Repository
+	BaseRef          git.RefName
+	BaseCommitID     string
+	HeadRepo         *repo_model.Repository
+	HeadGitRepo      *git.Repository
+	HeadRef          git.RefName
+	HeadCommitID     string
+	DirectComparison bool
+	MergeBase        string
+	Commits          []*git.Commit
+	NumFiles         int
+}
+
+func (ci *CompareInfo) IsSameRepository() bool {
+	return ci.BaseRepo.ID == ci.HeadRepo.ID
+}
+
+func (ci *CompareInfo) IsSameRef() bool {
+	return ci.IsSameRepository() && ci.BaseRef == ci.HeadRef
+}
+
+// GetCompareInfo generates and returns compare information between base and head branches of repositories.
+func GetCompareInfo(ctx context.Context, baseRepo, headRepo *repo_model.Repository, headGitRepo *git.Repository, baseRef, headRef git.RefName, directComparison, fileOnly bool) (_ *CompareInfo, err error) {
+	compareInfo := new(CompareInfo)
+
+	compareInfo.HeadCommitID, err = gitrepo.GetFullCommitID(ctx, headRepo, headRef.String())
+	if err != nil {
+		compareInfo.HeadCommitID = headRef.String()
+	}
+	compareInfo.BaseCommitID, err = gitrepo.GetFullCommitID(ctx, baseRepo, baseRef.String())
+	if err != nil {
+		compareInfo.BaseCommitID = baseRef.String()
+	}
+
+	compareInfo.MergeBase, err = gitrepo.MergeBaseFromRemote(ctx, baseRepo, headRepo, compareInfo.BaseCommitID, compareInfo.HeadCommitID)
+	if err == nil {
+		separator := "..."
+		startCommitID := compareInfo.MergeBase
+		if directComparison {
+			separator = ".."
+			startCommitID = compareInfo.BaseCommitID
+		}
+
+		// We have a common base - therefore we know that ... should work
+		if !fileOnly {
+			compareInfo.Commits, err = headGitRepo.ShowPrettyFormatLogToList(ctx, startCommitID+separator+headRef.String())
+			if err != nil {
+				return nil, fmt.Errorf("ShowPrettyFormatLogToList: %w", err)
+			}
+		} else {
+			compareInfo.Commits = []*git.Commit{}
+		}
+	} else {
+		compareInfo.Commits = []*git.Commit{}
+		compareInfo.MergeBase = compareInfo.BaseCommitID
+	}
+
+	if baseRepo.ID != headRepo.ID {
+		if err := gitrepo.FetchRemoteCommit(ctx, headRepo, baseRepo, compareInfo.BaseCommitID); err != nil {
+			return nil, fmt.Errorf("FetchRemoteCommit: %w", err)
+		}
+	}
+
+	// Count number of changed files.
+	// This probably should be removed as we need to use shortstat elsewhere
+	// Now there is git diff --shortstat but this appears to be slower than simply iterating with --nameonly
+	compareInfo.NumFiles, err = headGitRepo.GetDiffNumChangedFiles(compareInfo.BaseCommitID, compareInfo.HeadCommitID, directComparison)
+	if err != nil {
+		return nil, err
+	}
+	return compareInfo, nil
+}