Make Requests Processes and create process hierarchy. Associate OpenRepository with context. (#17125)

This PR registers requests with the process manager and manages hierarchy within the processes.

Git repos are then associated with a context, (usually the request's context) - with sub commands using this context as their base context.

Signed-off-by: Andrew Thornton <art27@cantab.net>

modules/git/batch_reader.go

@@ -28,17 +28,15 @@ type WriteCloserError interface {
 }
 
 // CatFileBatchCheck opens git cat-file --batch-check in the provided repo and returns a stdin pipe, a stdout reader and cancel function
-func CatFileBatchCheck(repoPath string) (WriteCloserError, *bufio.Reader, func()) {
+func CatFileBatchCheck(ctx context.Context, repoPath string) (WriteCloserError, *bufio.Reader, func()) {
 	batchStdinReader, batchStdinWriter := io.Pipe()
 	batchStdoutReader, batchStdoutWriter := io.Pipe()
-	ctx, ctxCancel := context.WithCancel(DefaultContext)
+	ctx, ctxCancel := context.WithCancel(ctx)
 	closed := make(chan struct{})
 	cancel := func() {
-		_ = batchStdinReader.Close()
-		_ = batchStdinWriter.Close()
-		_ = batchStdoutReader.Close()
-		_ = batchStdoutWriter.Close()
 		ctxCancel()
+		_ = batchStdoutReader.Close()
+		_ = batchStdinWriter.Close()
 		<-closed
 	}
 
@@ -67,19 +65,17 @@ func CatFileBatchCheck(repoPath string) (WriteCloserError, *bufio.Reader, func()
 }
 
 // CatFileBatch opens git cat-file --batch in the provided repo and returns a stdin pipe, a stdout reader and cancel function
-func CatFileBatch(repoPath string) (WriteCloserError, *bufio.Reader, func()) {
+func CatFileBatch(ctx context.Context, repoPath string) (WriteCloserError, *bufio.Reader, func()) {
 	// We often want to feed the commits in order into cat-file --batch, followed by their trees and sub trees as necessary.
 	// so let's create a batch stdin and stdout
 	batchStdinReader, batchStdinWriter := io.Pipe()
 	batchStdoutReader, batchStdoutWriter := nio.Pipe(buffer.New(32 * 1024))
-	ctx, ctxCancel := context.WithCancel(DefaultContext)
+	ctx, ctxCancel := context.WithCancel(ctx)
 	closed := make(chan struct{})
 	cancel := func() {
-		_ = batchStdinReader.Close()
+		ctxCancel()
 		_ = batchStdinWriter.Close()
 		_ = batchStdoutReader.Close()
-		_ = batchStdoutWriter.Close()
-		ctxCancel()
 		<-closed
 	}