gitserver: grpc: add new ChangedFiles method to gitserver client

cmd/gitserver/internal/server_grpc_logger.go

@@ -6,17 +6,15 @@ import (
 	"sync/atomic"
 	"time"
 
-	"google.golang.org/grpc/codes"
-
-	"github.com/sourcegraph/sourcegraph/cmd/gitserver/internal/urlredactor"
-	"github.com/sourcegraph/sourcegraph/internal/grpc/grpcutil"
-	"github.com/sourcegraph/sourcegraph/internal/vcs"
-
 	"github.com/sourcegraph/log"
+	"google.golang.org/grpc/codes"
 	"google.golang.org/grpc/status"
 
+	"github.com/sourcegraph/sourcegraph/cmd/gitserver/internal/urlredactor"
 	proto "github.com/sourcegraph/sourcegraph/internal/gitserver/v1"
+	"github.com/sourcegraph/sourcegraph/internal/grpc/grpcutil"
 	"github.com/sourcegraph/sourcegraph/internal/trace"
+	"github.com/sourcegraph/sourcegraph/internal/vcs"
 )
 
 // loggingGRPCServer is a wrapper around the provided GitserverServiceServer

internal/gitserver/client.go

@@ -6,6 +6,7 @@ import (
 	"io"
 	"io/fs"
 	"strings"
+	"sync"
 	"testing"
 	"time"
 
@@ -439,6 +440,14 @@ type Client interface {
 	// If the specified commit does not exist, a RevisionNotFoundError is returned.
 	NewFileReader(ctx context.Context, repo api.RepoName, commit api.CommitID, name string) (io.ReadCloser, error)
 
+	// ChangedFiles returns the list of files that have been added, modified, or
+	// deleted in the entire repository between the two given <tree-ish> identifiers (e.g., commit, branch, tag).
+	//
+	// If base is omitted, the parent of head is used as the base.
+	//
+	// If either the base or head <tree-ish> id does not exist, a gitdomain.RevisionNotFoundError is returned.
+	ChangedFiles(ctx context.Context, repo api.RepoName, base, head string) (ChangedFilesIterator, error)
+
 	// DiffSymbols performs a diff command which is expected to be parsed by our symbols package
 	DiffSymbols(ctx context.Context, repo api.RepoName, commitA, commitB api.CommitID) ([]byte, error)
 
@@ -1190,3 +1199,60 @@ func (c *clientImplementor) ListGitoliteRepos(ctx context.Context, gitoliteHost
 
 	return list, nil
 }
+
+// ChangedFilesIterator is an iterator for retrieving the status of changed files in a Git repository.
+// It allows iterating over the changed files and retrieving their paths and statuses.
+//
+// The caller must ensure that they call Close() when the iterator is no longer needed to release any associated resources.
+type ChangedFilesIterator interface {
+	// Next returns the next changed file's path and status.
+	//
+	// If there are no more changed files, Next returns an io.EOF error.
+	// If an error occurs during iteration, Next returns the error that occurred.
+	Next() (gitdomain.PathStatus, error)
+
+	// Close closes the iterator and releases any associated resources.
+	//
+	// It is important to call Close when the iterator is no longer needed to avoid resource leaks.
+	// After calling Close, any subsequent calls to Next will return an io.EOF error.
+	Close()
+}
+
+// NewChangedFilesIteratorFromSlice returns a new ChangedFilesIterator that iterates over the given slice of changed files (in order),
+// which is useful for testing.
+func NewChangedFilesIteratorFromSlice(files []gitdomain.PathStatus) ChangedFilesIterator {
+	return &changedFilesSliceIterator{files: files}
+}
+
+type changedFilesSliceIterator struct {
+	mu     sync.Mutex
+	files  []gitdomain.PathStatus
+	closed bool
+}
+
+func (c *changedFilesSliceIterator) Next() (gitdomain.PathStatus, error) {
+	c.mu.Lock()
+	defer c.mu.Unlock()
+
+	if c.closed {
+		return gitdomain.PathStatus{}, io.EOF
+	}
+
+	if len(c.files) == 0 {
+		return gitdomain.PathStatus{}, io.EOF
+	}
+
+	file := c.files[0]
+	c.files = c.files[1:]
+
+	return file, nil
+}
+
+func (c *changedFilesSliceIterator) Close() {
+	c.mu.Lock()
+	defer c.mu.Unlock()
+
+	c.closed = true
+}
+
+var _ ChangedFilesIterator = &changedFilesSliceIterator{}

internal/gitserver/client_test.go

@@ -2,6 +2,7 @@ package gitserver_test
 
 import (
 	"context"
+	"io"
 	"math/rand"
 	"os/exec"
 	"path/filepath"
@@ -20,6 +21,7 @@ import (
 	"github.com/sourcegraph/sourcegraph/internal/api"
 	"github.com/sourcegraph/sourcegraph/internal/extsvc/gitolite"
 	"github.com/sourcegraph/sourcegraph/internal/gitserver"
+	"github.com/sourcegraph/sourcegraph/internal/gitserver/gitdomain"
 	"github.com/sourcegraph/sourcegraph/internal/gitserver/protocol"
 	proto "github.com/sourcegraph/sourcegraph/internal/gitserver/v1"
 )
@@ -397,3 +399,48 @@ func (fuzzTime) Generate(rand *rand.Rand, _ int) reflect.Value {
 }
 
 var _ quick.Generator = fuzzTime{}
+
+func TestNewChangedFilesIteratorFromSlice(t *testing.T) {
+	t.Run("IterateThroughFiles", func(t *testing.T) {
+		files := []gitdomain.PathStatus{
+			{Path: "file1.txt", Status: gitdomain.AddedAMD},
+			{Path: "file2.txt", Status: gitdomain.ModifiedAMD},
+			{Path: "file3.txt", Status: gitdomain.DeletedAMD},
+		}
+
+		iter := gitserver.NewChangedFilesIteratorFromSlice(files)
+		defer iter.Close()
+
+		for i := 0; i < len(files); i++ {
+			file, err := iter.Next()
+			require.NoError(t, err)
+			require.Equal(t, files[i], file)
+		}
+
+		_, err := iter.Next()
+		require.Equal(t, io.EOF, err)
+	})
+
+	t.Run("EmptySlice", func(t *testing.T) {
+		iter := gitserver.NewChangedFilesIteratorFromSlice(nil)
+		defer iter.Close()
+
+		_, err := iter.Next()
+		require.Equal(t, io.EOF, err)
+	})
+
+	t.Run("Close", func(t *testing.T) {
+		files := []gitdomain.PathStatus{
+			{Path: "file1.txt", Status: gitdomain.AddedAMD},
+		}
+
+		iter := gitserver.NewChangedFilesIteratorFromSlice(files)
+
+		// Close should be idempotent
+		iter.Close()
+		iter.Close()
+
+		_, err := iter.Next()
+		require.Equal(t, io.EOF, err)
+	})
+}