Trait conserve::transport::Transport

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pub trait Transport: Send + Sync + Debug {
    // Required methods
    fn list_dir(&self, relpath: &str) -> Result<ListDir, Error>;
    fn read_file(&self, path: &str) -> Result<Bytes, Error>;
    fn create_dir(&self, relpath: &str) -> Result<(), Error>;
    fn write_file(&self, relpath: &str, content: &[u8]) -> Result<(), Error>;
    fn metadata(&self, relpath: &str) -> Result<Metadata, Error>;
    fn remove_file(&self, relpath: &str) -> Result<(), Error>;
    fn remove_dir_all(&self, relpath: &str) -> Result<(), Error>;
    fn sub_transport(&self, relpath: &str) -> Arc<dyn Transport>;

    // Provided method
    fn is_file(&self, path: &str) -> Result<bool, Error> { ... }
}

Expand description

Abstracted filesystem IO to access an archive.

This supports operations that are common across local filesystems, SFTP, and cloud storage, and that are intended to be sufficient to efficiently implement the Conserve format.

A transport has a root location, which will typically be the top directory of the Archive. Below that point everything is accessed with a relative path, expressed as a PathBuf.

All Transports must be Send + Sync, so they can be passed across or shared across threads.

Files in Conserve archives have bounded size and fit in memory so this does not need to support streaming or partial reads and writes.

Required Methods§

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fn list_dir(&self, relpath: &str) -> Result<ListDir, Error>

List a directory, separating out file and subdirectory names.

Names are in the arbitrary order that they’re returned from the transport.

Any error during iteration causes overall failure.

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fn read_file(&self, path: &str) -> Result<Bytes, Error>

Get one complete file into a caller-provided buffer.

Files in the archive are of bounded size, so it’s OK to always read them entirely into memory, and this is simple to support on all implementations.

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fn create_dir(&self, relpath: &str) -> Result<(), Error>

Create a directory, if it does not exist.

If the directory already exists, it’s not an error.

This function does not create missing parent directories.

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fn write_file(&self, relpath: &str, content: &[u8]) -> Result<(), Error>

Write a complete file.

As much as possible, the file should be written atomically so that it is only visible with the complete content. On a local filesystem the content is written to a temporary file and then renamed. If a temporary file is used, the name should start with crate::TMP_PREFIX.

If the file exists it is replaced. (Across transports, and particularly on S3, we can’t rely on detecting existing files.)

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