From patchwork Mon May 3 19:33:05 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: =?utf-8?b?TsOtY29sYXMgRi4gUi4gQS4gUHJhZG8=?= X-Patchwork-Id: 12189 Return-Path: X-Original-To: parsemail@patchwork.libcamera.org Delivered-To: parsemail@patchwork.libcamera.org Received: from lancelot.ideasonboard.com (lancelot.ideasonboard.com [92.243.16.209]) by patchwork.libcamera.org (Postfix) with ESMTPS id A4534BDE78 for ; Mon, 3 May 2021 19:34:00 +0000 (UTC) Received: from lancelot.ideasonboard.com (localhost [IPv6:::1]) by lancelot.ideasonboard.com (Postfix) with ESMTP id 466E76891E; Mon, 3 May 2021 21:34:00 +0200 (CEST) Received: from bhuna.collabora.co.uk (bhuna.collabora.co.uk [IPv6:2a00:1098:0:82:1000:25:2eeb:e3e3]) by lancelot.ideasonboard.com (Postfix) with ESMTPS id 47AEE688AE for ; Mon, 3 May 2021 21:33:59 +0200 (CEST) Received: from localhost.localdomain (unknown [IPv6:2804:14c:1a9:2978:995d:672b:100f:2fd9]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) (Authenticated sender: nfraprado) by bhuna.collabora.co.uk (Postfix) with ESMTPSA id 6C35B1F41E97; Mon, 3 May 2021 20:33:57 +0100 (BST) From: =?utf-8?b?TsOtY29sYXMgRi4gUi4gQS4gUHJhZG8=?= To: libcamera-devel@lists.libcamera.org Date: Mon, 3 May 2021 16:33:05 -0300 Message-Id: <20210503193307.108607-2-nfraprado@collabora.com> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20210503193307.108607-1-nfraprado@collabora.com> References: <20210503193307.108607-1-nfraprado@collabora.com> MIME-Version: 1.0 Subject: [libcamera-devel] [RFC PATCH v2 1/3] libcamera: camera: Make stop() idempotent X-BeenThere: libcamera-devel@lists.libcamera.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: kernel@collabora.com, =?utf-8?q?Andr=C3=A9_Almeida?= Errors-To: libcamera-devel-bounces@lists.libcamera.org Sender: "libcamera-devel" Make Camera::stop() idempotent so that it can be called in any state and consecutive times. When called in any state other than CameraRunning, it is a no-op. This simplifies the cleanup path for applications. Signed-off-by: Nícolas F. R. A. Prado --- Changes in v2: - Suggested by Kieran: - Add new isRunning() function instead of relying on isAccessAllowed() - Suggested by Laurent: - Make stop()'s description clearer src/libcamera/camera.cpp | 20 +++++++++++++++++--- 1 file changed, 17 insertions(+), 3 deletions(-) diff --git a/src/libcamera/camera.cpp b/src/libcamera/camera.cpp index 1340c266cc5f..1c6c76c7c01e 100644 --- a/src/libcamera/camera.cpp +++ b/src/libcamera/camera.cpp @@ -347,6 +347,7 @@ public: const std::set &streams); ~Private(); + bool isRunning() const; int isAccessAllowed(State state, bool allowDisconnected = false, const char *from = __builtin_FUNCTION()) const; int isAccessAllowed(State low, State high, @@ -388,6 +389,15 @@ static const char *const camera_state_names[] = { "Running", }; +bool Camera::Private::isRunning() const +{ + State currentState = state_.load(std::memory_order_acquire); + if (currentState == CameraRunning) + return true; + + return false; +} + int Camera::Private::isAccessAllowed(State state, bool allowDisconnected, const char *from) const { @@ -1061,9 +1071,10 @@ int Camera::start(const ControlList *controls) * This method stops capturing and processing requests immediately. All pending * requests are cancelled and complete synchronously in an error state. * - * \context This function may only be called when the camera is in the Running - * state as defined in \ref camera_operation, and shall be synchronized by the - * caller with other functions that affect the camera state. + * \context This function may be called in any camera state as defined in \ref + * camera_operation, and shall be synchronized by the caller with other + * functions that affect the camera state. If called when the camera isn't + * running, it is a no-op. * * \return 0 on success or a negative error code otherwise * \retval -ENODEV The camera has been disconnected from the system @@ -1073,6 +1084,9 @@ int Camera::stop() { Private *const d = LIBCAMERA_D_PTR(); + if (!d->isRunning()) + return 0; + int ret = d->isAccessAllowed(Private::CameraRunning); if (ret < 0) return ret;