From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from firstgate.proxmox.com (firstgate.proxmox.com [212.224.123.68]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits)) (No client certificate requested) by lists.proxmox.com (Postfix) with ESMTPS id C389C6A5E2 for ; Tue, 16 Feb 2021 18:08:04 +0100 (CET) Received: from firstgate.proxmox.com (localhost [127.0.0.1]) by firstgate.proxmox.com (Proxmox) with ESMTP id 7EB0318E60 for ; Tue, 16 Feb 2021 18:07:33 +0100 (CET) Received: from proxmox-new.maurer-it.com (proxmox-new.maurer-it.com [212.186.127.180]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits)) (No client certificate requested) by firstgate.proxmox.com (Proxmox) with ESMTPS id 54B4518DB5 for ; Tue, 16 Feb 2021 18:07:29 +0100 (CET) Received: from proxmox-new.maurer-it.com (localhost.localdomain [127.0.0.1]) by proxmox-new.maurer-it.com (Proxmox) with ESMTP id 18F4C461DB for ; Tue, 16 Feb 2021 18:07:29 +0100 (CET) From: Stefan Reiter To: pbs-devel@lists.proxmox.com Date: Tue, 16 Feb 2021 18:06:50 +0100 Message-Id: <20210216170710.31767-3-s.reiter@proxmox.com> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20210216170710.31767-1-s.reiter@proxmox.com> References: <20210216170710.31767-1-s.reiter@proxmox.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-SPAM-LEVEL: Spam detection results: 0 AWL -0.029 Adjusted score from AWL reputation of From: address KAM_DMARC_STATUS 0.01 Test Rule for DKIM or SPF Failure with Strict Alignment RCVD_IN_DNSWL_MED -2.3 Sender listed at https://www.dnswl.org/, medium trust SPF_HELO_NONE 0.001 SPF: HELO does not publish an SPF Record SPF_PASS -0.001 SPF: sender matches SPF record URIBL_BLOCKED 0.001 ADMINISTRATOR NOTICE: The query to URIBL was blocked. See http://wiki.apache.org/spamassassin/DnsBlocklists#dnsbl-block for more information. [mod.rs, aio.rs, sync.rs] Subject: [pbs-devel] [PATCH pxar 02/22] decoder: add peek() X-BeenThere: pbs-devel@lists.proxmox.com X-Mailman-Version: 2.1.29 Precedence: list List-Id: Proxmox Backup Server development discussion List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 16 Feb 2021 17:08:04 -0000 Allows peeking the current element, but will not advance the state (except for contents() and content_size() functions). Signed-off-by: Stefan Reiter --- src/accessor/mod.rs | 3 +++ src/decoder/aio.rs | 10 +++++++++- src/decoder/mod.rs | 19 +++++++++++++++++-- src/decoder/sync.rs | 10 +++++++++- 4 files changed, 38 insertions(+), 4 deletions(-) diff --git a/src/accessor/mod.rs b/src/accessor/mod.rs index d02dc13..aa1b3f6 100644 --- a/src/accessor/mod.rs +++ b/src/accessor/mod.rs @@ -293,6 +293,7 @@ impl AccessorImpl { let entry = decoder .next() .await + .transpose() .ok_or_else(|| io_format_err!("unexpected EOF while decoding file entry"))??; Ok(FileEntryImpl { input: self.input.clone(), @@ -334,6 +335,7 @@ impl AccessorImpl { let entry = decoder .next() .await + .transpose() .ok_or_else(|| io_format_err!("unexpected EOF while following a hardlink"))??; match entry.kind() { @@ -516,6 +518,7 @@ impl DirectoryImpl { let entry = decoder .next() .await + .transpose() .ok_or_else(|| io_format_err!("unexpected EOF while decoding directory entry"))??; Ok((entry, decoder)) } diff --git a/src/decoder/aio.rs b/src/decoder/aio.rs index 5cc6694..c553d45 100644 --- a/src/decoder/aio.rs +++ b/src/decoder/aio.rs @@ -53,7 +53,15 @@ impl Decoder { #[allow(clippy::should_implement_trait)] /// If this is a directory entry, get the next item inside the directory. pub async fn next(&mut self) -> Option> { - self.inner.next_do().await.transpose() + self.inner.next().await.transpose() + } + + /// If this is a directory entry, get the next item inside the directory. + /// Do not advance the cursor, so multiple calls to peek() will return the same entry, + /// and the next call to next() will read the item once again before moving on. + /// NOTE: This *will* advance the state for contents() and content_size()! + pub async fn peek(&mut self) -> Option> { + self.inner.peek().await.transpose() } /// Get a reader for the contents of the current entry, if the entry has contents. diff --git a/src/decoder/mod.rs b/src/decoder/mod.rs index 2a5e79a..041226d 100644 --- a/src/decoder/mod.rs +++ b/src/decoder/mod.rs @@ -155,6 +155,7 @@ pub(crate) struct DecoderImpl { path_lengths: Vec, state: State, with_goodbye_tables: bool, + peeked: Option>>, /// The random access code uses decoders for sub-ranges which may not end in a `PAYLOAD` for /// entries like FIFOs or sockets, so there we explicitly allow an item to terminate with EOF. @@ -218,6 +219,7 @@ impl DecoderImpl { path_lengths: Vec::new(), state: State::Begin, with_goodbye_tables: false, + peeked: None, eof_after_entry, }; @@ -227,8 +229,21 @@ impl DecoderImpl { } /// Get the next file entry, recursing into directories. - pub async fn next(&mut self) -> Option> { - self.next_do().await.transpose() + pub async fn next(&mut self) -> io::Result> { + if let Some(ent) = self.peeked.take() { + return ent; + } + self.next_do().await + } + + pub async fn peek(&mut self) -> io::Result> { + self.peeked = Some(self.next().await); + match &self.peeked { + Some(Ok(ent)) => Ok(ent.clone()), + // io::Error does not implement Clone... + Some(Err(err)) => Err(io_format_err!("{}", err)), + None => unreachable!() + } } async fn next_do(&mut self) -> io::Result> { diff --git a/src/decoder/sync.rs b/src/decoder/sync.rs index 85b4865..c6a1bc3 100644 --- a/src/decoder/sync.rs +++ b/src/decoder/sync.rs @@ -63,7 +63,15 @@ impl Decoder { #[allow(clippy::should_implement_trait)] /// If this is a directory entry, get the next item inside the directory. pub fn next(&mut self) -> Option> { - poll_result_once(self.inner.next_do()).transpose() + poll_result_once(self.inner.next()).transpose() + } + + /// If this is a directory entry, get the next item inside the directory. + /// Do not advance the cursor, so multiple calls to peek() will return the same entry, + /// and the next call to next() will read the item once again before moving on. + /// NOTE: This *will* advance the state for contents() and content_size()! + pub async fn peek(&mut self) -> Option> { + poll_result_once(self.inner.peek()).transpose() } /// Get a reader for the contents of the current entry, if the entry has contents. -- 2.20.1