meilisearch/milli/src/documents/builder.rs
mpostma aa6c5df0bc Implement documents format
document reader transform

remove update format

support document sequences

fix document transform

clean transform

improve error handling

add documents! macro

fix transform bug

fix tests

remove csv dependency

Add comments on the transform process

replace search cli

fmt

review edits

fix http ui

fix clippy warnings

Revert "fix clippy warnings"

This reverts commit a1ce3cd96e603633dbf43e9e0b12b2453c9c5620.

fix review comments

remove smallvec in transform loop

review edits
2021-09-21 16:58:33 +02:00

81 lines
2.5 KiB
Rust

use std::io;
use byteorder::{BigEndian, WriteBytesExt};
use serde::ser::Serialize;
use super::serde::DocumentSerializer;
use super::{ByteCounter, DocumentsBatchIndex, DocumentsMetadata, Error};
/// The `DocumentsBatchBuilder` provides a way to build a documents batch in the intermediary
/// format used by milli.
///
/// The writer used by the DocumentBatchBuilder can be read using a `DocumentBatchReader` to
/// iterate other the documents.
///
/// ## example:
/// ```
/// use milli::documents::DocumentBatchBuilder;
/// use serde_json::json;
/// use std::io::Cursor;
///
/// let mut writer = Cursor::new(Vec::new());
/// let mut builder = DocumentBatchBuilder::new(&mut writer).unwrap();
/// builder.add_documents(json!({"id": 1, "name": "foo"})).unwrap();
/// builder.finish().unwrap();
/// ```
pub struct DocumentBatchBuilder<W> {
serializer: DocumentSerializer<W>,
}
impl<W: io::Write + io::Seek> DocumentBatchBuilder<W> {
pub fn new(writer: W) -> Result<Self, Error> {
let index = DocumentsBatchIndex::new();
let mut writer = ByteCounter::new(writer);
// add space to write the offset of the metadata at the end of the writer
writer.write_u64::<BigEndian>(0)?;
let serializer =
DocumentSerializer { writer, buffer: Vec::new(), index, count: 0, allow_seq: true };
Ok(Self { serializer })
}
/// Returns the number of documents that have been written to the builder.
pub fn len(&self) -> usize {
self.serializer.count
}
/// This method must be called after the document addition is terminated. It will put the
/// metadata at the end of the file, and write the metadata offset at the beginning on the
/// file.
pub fn finish(self) -> Result<(), Error> {
let DocumentSerializer {
writer: ByteCounter { mut writer, count: offset },
index,
count,
..
} = self.serializer;
let meta = DocumentsMetadata { count, index };
bincode::serialize_into(&mut writer, &meta)?;
writer.seek(io::SeekFrom::Start(0))?;
writer.write_u64::<BigEndian>(offset as u64)?;
writer.flush()?;
Ok(())
}
/// Adds documents to the builder.
///
/// The internal index is updated with the fields found
/// in the documents. Document must either be a map or a sequences of map, anything else will
/// fail.
pub fn add_documents<T: Serialize>(&mut self, document: T) -> Result<(), Error> {
document.serialize(&mut self.serializer)?;
Ok(())
}
}