ReconstructionService

ReconstructionService defines the primary interface responsible for reconstructing files from their chunks, either on disk or as a stream.
This service communicates directly with a ChunkSource to obtain the required data and reassemble the file.

It serves as the core component of the restoration process within rac-delta.

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Methods

Method	Returns	Description
reconstruct_file(entry, output_path, chunk_source, options, cb)	Result<(), ReconstructionError>	Reconstruct a single file in disk.
reconstruct_all(plan, output_dir, chunk_source, options)	Result<(), ReconstructionError>	Reconstruct all files from a DeltaPlan in disk.
reconstruct_to_stream(entry, chunk_source)	Result<Pin<Box<dyn AsyncRead + Send + Sync>>, ReconstructionError>	Reconstruct a file in memory and returns it as a Readable stream.

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ReconstructionError

Custom error enum for results of ReconstructionService. (Uses thiserror)

pub enum ReconstructionError {
    #[error("I/O error: {0}")]
    Io(#[from] std::io::Error),

    #[error("Chunk '{0}' not found")]
    ChunkNotFound(String),

    #[error("Hash mismatch for file '{0}'")]
    HashMismatch(String),

    #[error("Failed to read chunk '{0}'")]
    ChunkReadError(String),

    #[error("Reconstruction failed: {0}")]
    Other(String),
}

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ReconstructionOptions

Options for the reconstruction progress:

pub struct ReconstructionOptions {
    pub force_rebuild: Option<bool>,
    pub verify_after_rebuild: Option<bool>,
    pub in_place_reconstruction_threshold: Option<u64>,
    pub file_concurrency: Option<usize>,
    pub on_progress: Option<Arc<dyn Fn(f64, usize, Option<f64>, Option<usize>) + Send + Sync>>,
}

Parameter	Type	Description
force_rebuild	Option<bool>	Force to rebuild even if hash file matches.
verify_after_rebuild	Option<bool>	Verifies the reconstructed file hash after finishing. If hash does not match, an error is thrown.
in_place_reconstruction_threshold	Option<u64>	Minimum file size (in bytes) required to perform an in-place reconstruction instead of using a temporary file.
file_concurrency	Option<usize>	How many files will reconstruct concurrently (default value is 5).
on_progress	Option<Arc<dyn Fn(f64, usize, Option<f64>, Option<usize>) + Send + Sync>>	Callback that returns disk usage and optional network speed (only for storage chunk sources via streaming download-reconstruction).

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Method Details

reconstruct_file(entry, output_path, chunk_source, options, cb)

Reconstruct a single file from a FileEntry in disk.

Parameters:

Name	Type	Description
entry	&FileEntry	The FileEntry containing the list of chunks and path of the file.
outputPath	&Path	The path where the file will be reconstructed.
chunkSource	&dyn ChunkSource	The chunk source implementation where the chunks will be retrieved.
options	Option<&ReconstructionOptions>	Options for reconstruction.
cb	Option<FileProgressCallback>	Optional callback for progress.

pub type FileProgressCallback = Arc<dyn Fn(f64, usize, Option<usize>) + Send + Sync>;

Returns: Result<(), ReconstructionError

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reconstruct_all(plan, output_dir, chunk_source, options)

Reconstruct all files from given DeltaPlan in disk.

Parameters:

Name	Type	Description
plan	&DeltaPlan	The DeltaPlan containing the files to be reconstructed.
output_dir	&Path	The path where the files will be reconstructed.
chunk_source	Arc<dyn ChunkSource>	The chunk source implementation where the chunks will be retrieved.
options	Option<&ReconstructionOptions>	Options for reconstruction.

Returns: Result<(), ReconstructionError>

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reconstruct_to_stream(entry, chunk_source)

Reconstruct a file in memory and returns it as a stream.

Parameters:

Name	Type	Description
entry	FileEntry	The FileEntry containing the list of chunks and path of the file.
chunk_source	Arc<dyn ChunkSource + Send + Sync>	The chunk source implementation where the chunks will be retrieved.

Returns: Result<Pin<Box<dyn AsyncRead + Send + Sync>>, ReconstructionError>

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Related

• DeltaPlan
• FileEntry
• ChunkSource