152 lines
4.1 KiB
Rust
152 lines
4.1 KiB
Rust
//! This crate provides utilities for easily communicating between backend &
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//! frontend and ensuring the same logic for encoding and decoding binary data,
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//! and 3-way-merging documents in Rust and JavaScript.
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//!
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//! The crate is designed to be used as a Rust library and as a
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//! TypeScript/JavaScript package through WebAssembly (WASM).
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//!
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//! # Modules
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//!
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//! - `errors`: Contains error types used in this crate.
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use core::str;
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use base64::{Engine as _, engine::general_purpose::STANDARD};
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use cursor::TextWithCursors;
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use errors::SyncLibError;
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use wasm_bindgen::prelude::*;
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pub mod cursor;
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pub mod errors;
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/// Encode binary data for easy transport over HTTP. Inverse of
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/// `base64_to_bytes`.
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///
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/// # Arguments
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///
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/// - `input`: The binary data to encode.
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///
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/// # Returns
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///
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/// The base64-encoded string.
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///
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/// # Panics
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///
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/// If the input is not valid UTF-8.
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#[wasm_bindgen(js_name = bytesToBase64)]
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#[must_use]
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pub fn bytes_to_base64(input: &[u8]) -> String {
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set_panic_hook();
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STANDARD.encode(input)
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}
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/// Inverse of `bytes_to_base64`.
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/// Decode base64-encoded data into binary data.
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///
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/// # Arguments
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///
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/// - `input`: The base64-encoded string.
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///
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/// # Returns
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///
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/// The decoded binary data.
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///
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/// # Errors
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///
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/// If the input is not valid base64.
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#[wasm_bindgen(js_name = base64ToBytes)]
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pub fn base64_to_bytes(input: &str) -> Result<Vec<u8>, SyncLibError> {
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set_panic_hook();
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STANDARD.decode(input).map_err(SyncLibError::from)
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}
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/// Merge two documents with a common parent. Relies on `reconcile::reconcile`
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/// for texts and returns the right document as-is if either of the updated
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/// documents is binary.
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///
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/// # Arguments
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///
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/// - `parent`: The common parent document.
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/// - `left`: The left document updated by one user.
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/// - `right`: The right document updated by another user.
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///
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/// # Returns
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///
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/// The merged document.
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///
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/// # Panics
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///
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/// If any of the input documents are not valid UTF-8 strings.
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#[wasm_bindgen]
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#[must_use]
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pub fn merge(parent: &[u8], left: &[u8], right: &[u8]) -> Vec<u8> {
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set_panic_hook();
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if is_binary(parent) || is_binary(left) || is_binary(right) {
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right.to_vec()
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} else {
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reconcile::reconcile(
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str::from_utf8(parent).expect("parent must be valid UTF-8 because it's not binary"),
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str::from_utf8(left).expect("left must be valid UTF-8 because it's not binary"),
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str::from_utf8(right).expect("right must be valid UTF-8 because it's not binary"),
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)
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.into_bytes()
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}
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}
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/// WASM wrapper around `reconcile::reconcile` for merging text.
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#[wasm_bindgen(js_name = mergeText)]
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#[must_use]
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pub fn merge_text(parent: &str, left: &str, right: &str) -> String {
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set_panic_hook();
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reconcile::reconcile(parent, left, right)
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}
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/// WASM wrapper around `reconcile::reconcile_with_cursors` for merging text.
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#[wasm_bindgen(js_name = mergeTextWithCursors)]
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#[must_use]
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pub fn merge_text_with_cursors(
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parent: &str,
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left: TextWithCursors,
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right: TextWithCursors,
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) -> TextWithCursors {
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set_panic_hook();
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reconcile::reconcile_with_cursors(parent, left.into(), right.into()).into()
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}
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/// Heuristically determine if the given data is a binary or a text file's
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/// content.
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#[wasm_bindgen(js_name = isBinary)]
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#[must_use]
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pub fn is_binary(data: &[u8]) -> bool {
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set_panic_hook();
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if data.contains(&0) {
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// Even though the NUL character is valid in UTF-8, it's highly suspicious in
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// human-readable text.
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return true;
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}
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std::str::from_utf8(data).is_err()
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}
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/// We don't want to support merging structured data like JSON, YAML, etc.
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#[wasm_bindgen(js_name = isFileTypeMergable)]
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#[must_use]
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pub fn is_file_type_mergable(path_or_file_name: &str) -> bool {
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set_panic_hook();
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let file_extension = path_or_file_name.split('.').next_back().unwrap_or_default();
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matches!(file_extension.to_lowercase().as_str(), "md" | "txt")
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}
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fn set_panic_hook() {
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// https://github.com/rustwasm/console_error_panic_hook#readme
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#[cfg(feature = "console_error_panic_hook")]
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console_error_panic_hook::set_once();
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}
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