Allow to mark files in a PR as viewed (#19007)

Users can now mark files in PRs as viewed, resulting in them not being shown again by default when they reopen the PR again.

models/pull/review_state.go

@@ -0,0 +1,139 @@
+// Copyright 2022 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 (
+	"context"
+	"fmt"
+
+	"code.gitea.io/gitea/models/db"
+	"code.gitea.io/gitea/modules/log"
+	"code.gitea.io/gitea/modules/timeutil"
+)
+
+// ViewedState stores for a file in which state it is currently viewed
+type ViewedState uint8
+
+const (
+	Unviewed   ViewedState = iota
+	HasChanged             // cannot be set from the UI/ API, only internally
+	Viewed
+)
+
+func (viewedState ViewedState) String() string {
+	switch viewedState {
+	case Unviewed:
+		return "unviewed"
+	case HasChanged:
+		return "has-changed"
+	case Viewed:
+		return "viewed"
+	default:
+		return fmt.Sprintf("unknown(value=%d)", viewedState)
+	}
+}
+
+// ReviewState stores for a user-PR-commit combination which files the user has already viewed
+type ReviewState struct {
+	ID           int64                  `xorm:"pk autoincr"`
+	UserID       int64                  `xorm:"NOT NULL UNIQUE(pull_commit_user)"`
+	PullID       int64                  `xorm:"NOT NULL UNIQUE(pull_commit_user) DEFAULT 0"`   // Which PR was the review on?
+	CommitSHA    string                 `xorm:"NOT NULL VARCHAR(40) UNIQUE(pull_commit_user)"` // Which commit was the head commit for the review?
+	UpdatedFiles map[string]ViewedState `xorm:"NOT NULL LONGTEXT JSON"`                        // Stores for each of the changed files of a PR whether they have been viewed, changed since last viewed, or not viewed
+	UpdatedUnix  timeutil.TimeStamp     `xorm:"updated"`                                       // Is an accurate indicator of the order of commits as we do not expect it to be possible to make reviews on previous commits
+}
+
+func init() {
+	db.RegisterModel(new(ReviewState))
+}
+
+// GetReviewState returns the ReviewState with all given values prefilled, whether or not it exists in the database.
+// If the review didn't exist before in the database, it won't afterwards either.
+// The returned boolean shows whether the review exists in the database
+func GetReviewState(ctx context.Context, userID, pullID int64, commitSHA string) (*ReviewState, bool, error) {
+	review := &ReviewState{UserID: userID, PullID: pullID, CommitSHA: commitSHA}
+	has, err := db.GetEngine(ctx).Get(review)
+	return review, has, err
+}
+
+// UpdateReviewState updates the given review inside the database, regardless of whether it existed before or not
+// The given map of files with their viewed state will be merged with the previous review, if present
+func UpdateReviewState(ctx context.Context, userID, pullID int64, commitSHA string, updatedFiles map[string]ViewedState) error {
+	log.Trace("Updating review for user %d, repo %d, commit %s with the updated files %v.", userID, pullID, commitSHA, updatedFiles)
+
+	review, exists, err := GetReviewState(ctx, userID, pullID, commitSHA)
+	if err != nil {
+		return err
+	}
+
+	if exists {
+		review.UpdatedFiles = mergeFiles(review.UpdatedFiles, updatedFiles)
+	} else if previousReview, err := getNewestReviewStateApartFrom(ctx, userID, pullID, commitSHA); err != nil {
+		return err
+
+		// Overwrite the viewed files of the previous review if present
+	} else if previousReview != nil {
+		review.UpdatedFiles = mergeFiles(previousReview.UpdatedFiles, updatedFiles)
+	} else {
+		review.UpdatedFiles = updatedFiles
+	}
+
+	// Insert or Update review
+	engine := db.GetEngine(ctx)
+	if !exists {
+		log.Trace("Inserting new review for user %d, repo %d, commit %s with the updated files %v.", userID, pullID, commitSHA, review.UpdatedFiles)
+		_, err := engine.Insert(review)
+		return err
+	}
+	log.Trace("Updating already existing review with ID %d (user %d, repo %d, commit %s) with the updated files %v.", review.ID, userID, pullID, commitSHA, review.UpdatedFiles)
+	_, err = engine.ID(review.ID).Update(&ReviewState{UpdatedFiles: review.UpdatedFiles})
+	return err
+}
+
+// mergeFiles merges the given maps of files with their viewing state into one map.
+// Values from oldFiles will be overridden with values from newFiles
+func mergeFiles(oldFiles, newFiles map[string]ViewedState) map[string]ViewedState {
+	if oldFiles == nil {
+		return newFiles
+	} else if newFiles == nil {
+		return oldFiles
+	}
+
+	for file, viewed := range newFiles {
+		oldFiles[file] = viewed
+	}
+	return oldFiles
+}
+
+// GetNewestReviewState gets the newest review of the current user in the current PR.
+// The returned PR Review will be nil if the user has not yet reviewed this PR.
+func GetNewestReviewState(ctx context.Context, userID, pullID int64) (*ReviewState, error) {
+	var review ReviewState
+	has, err := db.GetEngine(ctx).Where("user_id = ?", userID).And("pull_id = ?", pullID).OrderBy("updated_unix DESC").Get(&review)
+	if err != nil || !has {
+		return nil, err
+	}
+	return &review, err
+}
+
+// getNewestReviewStateApartFrom is like GetNewestReview, except that the second newest review will be returned if the newest review points at the given commit.
+// The returned PR Review will be nil if the user has not yet reviewed this PR.
+func getNewestReviewStateApartFrom(ctx context.Context, userID, pullID int64, commitSHA string) (*ReviewState, error) {
+	var reviews []ReviewState
+	err := db.GetEngine(ctx).Where("user_id = ?", userID).And("pull_id = ?", pullID).OrderBy("updated_unix DESC").Limit(2).Find(&reviews)
+	// It would also be possible to use ".And("commit_sha != ?", commitSHA)" instead of the error handling below
+	// However, benchmarks show drastically improved performance by not doing that
+
+	// Error cases in which no review should be returned
+	if err != nil || len(reviews) == 0 || (len(reviews) == 1 && reviews[0].CommitSHA == commitSHA) {
+		return nil, err
+
+		// The first review points at the commit to exclude, hence skip to the second review
+	} else if len(reviews) >= 2 && reviews[0].CommitSHA == commitSHA {
+		return &reviews[1], nil
+	}
+
+	// As we have no error cases left, the result must be the first element in the list
+	return &reviews[0], nil
+}