[pbs-devel] [PATCH v3 pxar 13/58] format: add pxar format version entry
Christian Ebner
c.ebner at proxmox.com
Wed Apr 3 15:31:59 CEST 2024
On 4/3/24 13:41, Fabian Grünbichler wrote:
>> @@ -258,7 +261,16 @@ impl<I: SeqRead> DecoderImpl<I> {
>> loop {
>> match self.state {
>> State::Eof => return Ok(None),
>> - State::Begin => return self.read_next_entry().await.map(Some),
>> + State::Begin => {
>> + let entry = self.read_next_entry().await.map(Some);
>> + if let Ok(Some(ref entry)) = entry {
>> + if let EntryKind::Version(version) = entry.kind() {
>> + self.version = version.clone();
>> + return self.read_next_entry().await.map(Some);
>> + }
>> + }
>> + return entry;
>
> a bit unsure here, if we want to enforce the order, wouldn't it be more
> clean to transition to a new state here rather than adding more nested
> ifs over time? ;)
Okay, agreed, will try to de-clutter this a bit by adding a Prelude
state as suggested in your other reply.
>> + 1u64 => Ok(format::FormatVersion::Version1),
>
> this should never happen though, right?
No, right... Will remove it.
>
>> + 2u64 => Ok(format::FormatVersion::Version2),
>
> also this (cted below)
>
>> + _ => io_bail!("unexpected pxar format version"),
>
> this should maybe include the value? ;)
Okay, will add that.
>
>> + }
>> + }
>> }
>>
>> /// Reader for file contents inside a pxar archive.
>> diff --git a/src/encoder/mod.rs b/src/encoder/mod.rs
>> index 88c0ed5..9270153 100644
>> --- a/src/encoder/mod.rs
>> +++ b/src/encoder/mod.rs
>> @@ -17,7 +17,7 @@ use endian_trait::Endian;
>>
>> use crate::binary_tree_array;
>> use crate::decoder::{self, SeqRead};
>> -use crate::format::{self, GoodbyeItem, PayloadRef};
>> +use crate::format::{self, FormatVersion, GoodbyeItem, PayloadRef};
>> use crate::Metadata;
>>
>> pub mod aio;
>> @@ -307,6 +307,8 @@ pub(crate) struct EncoderImpl<'a, T: SeqWrite + 'a> {
>> /// Since only the "current" entry can be actively writing files, we share the file copy
>> /// buffer.
>> file_copy_buffer: Arc<Mutex<Vec<u8>>>,
>> + /// Pxar format version to encode
>> + version: format::FormatVersion,
>> }
>>
>> impl<'a, T: SeqWrite + 'a> EncoderImpl<'a, T> {
>> @@ -320,11 +322,14 @@ impl<'a, T: SeqWrite + 'a> EncoderImpl<'a, T> {
>> }
>>
>> let mut state = EncoderState::default();
>> - if let Some(payload_output) = payload_output.as_mut() {
>> + let version = if let Some(payload_output) = payload_output.as_mut() {
>> let header = format::Header::with_content_size(format::PXAR_PAYLOAD_START_MARKER, 0);
>> header.check_header_size()?;
>> seq_write_struct(payload_output, header, &mut state.payload_write_position).await?;
>> - }
>> + format::FormatVersion::Version2
>> + } else {
>> + format::FormatVersion::default()
>
> shouldn't this be Version1 instead of default()? they are the same
> *now*, but that might not be the case forever?
Okay, will set this to the new version.
>
>> + };
>>
>> let mut this = Self {
>> output,
>> @@ -334,8 +339,10 @@ impl<'a, T: SeqWrite + 'a> EncoderImpl<'a, T> {
>> file_copy_buffer: Arc::new(Mutex::new(unsafe {
>> crate::util::vec_new_uninitialized(1024 * 1024)
>> })),
>> + version,
>> };
>>
>> + this.encode_format_version().await?;
>> this.encode_metadata(metadata).await?;
>> let state = this.state_mut()?;
>> state.files_offset = state.position();
>> @@ -522,6 +529,10 @@ impl<'a, T: SeqWrite + 'a> EncoderImpl<'a, T> {
>> file_size: u64,
>> payload_offset: PayloadOffset,
>> ) -> io::Result<()> {
>> + if self.version == FormatVersion::Version1 {
>> + io_bail!("payload references not supported pxar format version 1");
>> + }
>> +
>> if self.payload_output.as_mut().is_none() {
>> io_bail!("unable to add payload reference");
>> }
>> @@ -729,6 +740,26 @@ impl<'a, T: SeqWrite + 'a> EncoderImpl<'a, T> {
>> Ok(())
>> }
>>
>> + async fn encode_format_version(&mut self) -> io::Result<()> {
>> + let version_bytes = match self.version {
>> + format::FormatVersion::Version1 => return Ok(()),
>> + format::FormatVersion::Version2 => 2u64.to_le_bytes(),
>
> (cted from above) and this here should maybe go together?
Not sure I understand, above is in the decoder, this in the encoder...
What was your intention? Move the encoding/decoding to the FormatVersion
type?
>
>> + };
>> +
>> + let (output, state) = self.output_state()?;
>> + if state.write_position != 0 {
>> + io_bail!("pxar format version must be encoded at the beginning of an archive");
>
> should this also be enforced while decoding?
Okay, will see to add a check for that as well.
>
> should we also encode a/the version of the payload archive?
The payload archive has the PAYLOAD_START_MARKER, which can be changed
just like the pxar entries v2?
>
>> + }
>> +
>> + seq_write_pxar_entry(
>> + output,
>> + format::PXAR_FORMAT_VERSION,
>> + &version_bytes,
>> + &mut state.write_position,
>> + )
>> + .await
>> + }
>> +
>> async fn encode_metadata(&mut self, metadata: &Metadata) -> io::Result<()> {
>> let (output, state) = self.output_state()?;
>> seq_write_pxar_struct_entry(
>> diff --git a/src/format/mod.rs b/src/format/mod.rs
>> index a672d19..2bf33c9 100644
>> --- a/src/format/mod.rs
>> +++ b/src/format/mod.rs
>> @@ -6,6 +6,7 @@
>> //! item data.
>> //!
>> //! An archive contains items in the following order:
>> +//! * `FORMAT_VERSION` -- (optional for v1), version of encoding format
>> //! * `ENTRY` -- containing general stat() data and related bits
>> //! * `XATTR` -- one extended attribute
>> //! * ... -- more of these when there are multiple defined
>> @@ -80,6 +81,8 @@ pub mod mode {
>> }
>>
>> // Generated by `cargo run --example mk-format-hashes`
>> +/// Pxar format version entry, fallback to version 1 if not present
>> +pub const PXAR_FORMAT_VERSION: u64 = 0x730f6c75df16a40d;
>> /// Beginning of an entry (current version).
>> pub const PXAR_ENTRY: u64 = 0xd5956474e588acef;
>> /// Previous version of the entry struct
>> @@ -186,6 +189,7 @@ impl Header {
>> impl Display for Header {
>> fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
>> let readable = match self.htype {
>> + PXAR_FORMAT_VERSION => "FORMAT_VERSION",
>> PXAR_FILENAME => "FILENAME",
>> PXAR_SYMLINK => "SYMLINK",
>> PXAR_HARDLINK => "HARDLINK",
>> @@ -551,6 +555,13 @@ impl From<&std::fs::Metadata> for Stat {
>> }
>> }
>>
>> +#[derive(Clone, Debug, Default, PartialEq)]
>> +pub enum FormatVersion {
>> + #[default]
>> + Version1,
>> + Version2,
>> +}
>> +
>> #[derive(Clone, Debug)]
>> pub struct Filename {
>> pub name: Vec<u8>,
>> diff --git a/src/lib.rs b/src/lib.rs
>> index ef81a85..a87b5ac 100644
>> --- a/src/lib.rs
>> +++ b/src/lib.rs
>> @@ -342,6 +342,9 @@ impl Acl {
>> /// Identifies whether the entry is a file, symlink, directory, etc.
>> #[derive(Clone, Debug)]
>> pub enum EntryKind {
>> + /// Pxar file format version
>> + Version(format::FormatVersion),
>> +
>> /// Symbolic links.
>> Symlink(format::Symlink),
>>
>> --
>> 2.39.2
>>
>>
>>
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>>
>>
>>
>
>
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