57 lines
1.3 KiB
Rust
57 lines
1.3 KiB
Rust
use serde::Serialize;
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use serde::de::DeserializeOwned;
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use bson::Document;
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use std::fs::File;
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use std::io::{BufReader, Seek, Write};
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use std::error::Error;
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pub struct Collection<T>
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{
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pub entries: Vec<T>
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}
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impl<T> Collection<T>{
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fn get(&self) -> Option<&T>{
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self.entries.get(0)
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}
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fn new( entries: Vec<T>) -> Collection<T>{
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Collection{
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entries:entries
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}
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}
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}
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impl<T> Collection<T>
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where
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T : Serialize
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{
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pub fn save<W>(&self, mut writer : W) -> Result<(), Box<dyn Error>>
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where W : Write {
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for a in self.entries.iter(){
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let d = bson::to_document(a)?;
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d.to_writer(&mut writer)?;
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}
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Ok(())
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}
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}
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impl<T> Collection<T>
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where
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T: DeserializeOwned
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{
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pub fn load(file: File) -> Result<Collection<T>, Box<dyn Error>>{
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let n = file.metadata()?.len();
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let mut reader = BufReader::new(file);
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let mut current_position = reader.stream_position()?;
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let mut entries = Vec::new();
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while current_position < n{
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let d = Document::from_reader(&mut reader)?;
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let h: T = bson::from_document(d)?;
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entries.push(h);
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current_position = reader.stream_position()?;
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}
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Ok(Collection::new( entries))
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}
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} |