fune/servo/components/style/encoding_support.rs

/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

//! Parsing stylesheets from bytes (not `&str`).

extern crate encoding_rs;

use context::QuirksMode;
use cssparser::{stylesheet_encoding, EncodingSupport};
use error_reporting::ParseErrorReporter;
use media_queries::MediaList;
use servo_arc::Arc;
use shared_lock::SharedRwLock;
use std::borrow::Cow;
use std::str;
use stylesheets::{Stylesheet, StylesheetLoader, Origin, UrlExtraData};

struct EncodingRs;

impl EncodingSupport for EncodingRs {
    type Encoding = &'static encoding_rs::Encoding;

    fn utf8() -> Self::Encoding {
        encoding_rs::UTF_8
    }

    fn is_utf16_be_or_le(encoding: &Self::Encoding) -> bool {
        *encoding == encoding_rs::UTF_16LE ||
        *encoding == encoding_rs::UTF_16BE
    }

    fn from_label(ascii_label: &[u8]) -> Option<Self::Encoding> {
        encoding_rs::Encoding::for_label(ascii_label)
    }
}

fn decode_stylesheet_bytes<'a>(css: &'a [u8], protocol_encoding_label: Option<&str>,
                               environment_encoding: Option<&'static encoding_rs::Encoding>)
                               -> Cow<'a, str> {
    let fallback_encoding = stylesheet_encoding::<EncodingRs>(
        css, protocol_encoding_label.map(str::as_bytes), environment_encoding);
    let (result, _used_encoding, _) = fallback_encoding.decode(&css);
    // FIXME record used encoding for environment encoding of @import
    result
}

impl Stylesheet {
    /// Parse a stylesheet from a set of bytes, potentially received over the
    /// network.
    ///
    /// Takes care of decoding the network bytes and forwards the resulting
    /// string to `Stylesheet::from_str`.
    pub fn from_bytes<R>(bytes: &[u8],
                         url_data: UrlExtraData,
                         protocol_encoding_label: Option<&str>,
                         environment_encoding: Option<&'static encoding_rs::Encoding>,
                         origin: Origin,
                         media: MediaList,
                         shared_lock: SharedRwLock,
                         stylesheet_loader: Option<&StylesheetLoader>,
                         error_reporter: &R,
                         quirks_mode: QuirksMode)
                         -> Stylesheet
        where R: ParseErrorReporter
    {
        let string = decode_stylesheet_bytes(bytes, protocol_encoding_label, environment_encoding);
        Stylesheet::from_str(&string,
                             url_data,
                             origin,
                             Arc::new(shared_lock.wrap(media)),
                             shared_lock,
                             stylesheet_loader,
                             error_reporter,
                             quirks_mode,
                             0)
    }

    /// Updates an empty stylesheet with a set of bytes that reached over the
    /// network.
    pub fn update_from_bytes<R>(existing: &Stylesheet,
                                bytes: &[u8],
                                protocol_encoding_label: Option<&str>,
                                environment_encoding: Option<&'static encoding_rs::Encoding>,
                                url_data: UrlExtraData,
                                stylesheet_loader: Option<&StylesheetLoader>,
                                error_reporter: &R)
        where R: ParseErrorReporter
    {
        let string = decode_stylesheet_bytes(bytes, protocol_encoding_label, environment_encoding);
        Self::update_from_str(existing,
                              &string,
                              url_data,
                              stylesheet_loader,
                              error_reporter,
                              0)
    }
}