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/* 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
//! Servo-specific logic for CSS url() values.
use crate::derives::*;
use crate::parser::ParserContext;
use crate::stylesheets::CorsMode;
use crate::values::computed::{Context, ToComputedValue};
use servo_arc::Arc;
use std::fmt::{self, Write};
use std::ops::Deref;
use style_traits::{CssWriter, ToCss};
use to_shmem::{SharedMemoryBuilder, ToShmem};
use url::Url;
/// A CSS url() value for servo.
///
/// Servo eagerly resolves SpecifiedUrls, which it can then take advantage of
/// when computing values. In contrast, Gecko uses a different URL backend, so
/// eagerly resolving with rust-url would be duplicated work.
///
/// However, this approach is still not necessarily optimal: See
#[derive(Clone, Debug, Deserialize, MallocSizeOf, Serialize, SpecifiedValueInfo)]
#[css(function = "url")]
#[repr(C)]
pub struct CssUrl(#[ignore_malloc_size_of = "Arc"] pub Arc<CssUrlData>);
/// Data shared between CssUrls.
///
#[derive(Debug, Deserialize, MallocSizeOf, Serialize, SpecifiedValueInfo)]
#[repr(C)]
pub struct CssUrlData {
/// The original URI. This might be optional since we may insert computed
/// values of images into the cascade directly, and we don't bother to
/// convert their serialization.
///
/// Refcounted since cloning this should be cheap and data: uris can be
/// really large.
#[ignore_malloc_size_of = "Arc"]
original: Option<Arc<String>>,
/// The resolved value for the url, if valid.
#[ignore_malloc_size_of = "Arc"]
resolved: Option<Arc<Url>>,
}
impl ToShmem for CssUrl {
fn to_shmem(&self, _builder: &mut SharedMemoryBuilder) -> to_shmem::Result<Self> {
unimplemented!("If servo wants to share stylesheets across processes, ToShmem for Url must be implemented");
}
}
impl Deref for CssUrl {
type Target = CssUrlData;
fn deref(&self) -> &Self::Target {
&self.0
}
}
impl CssUrl {
/// Try to parse a URL from a string value that is a valid CSS token for a
/// URL.
///
/// FIXME(emilio): Should honor CorsMode.
pub(super) fn new_from_string(
url: String,
context: &ParserContext,
_cors_mode: CorsMode,
) -> Self {
let serialization = Arc::new(url);
// If the original url is empty, then the resolved url is considered invalid.
let resolved = (!serialization.is_empty())
.then(|| context.url_data.0.join(&serialization))
.and_then(Result::ok)
.map(Arc::new);
CssUrl(Arc::new(CssUrlData {
original: Some(serialization),
resolved: resolved,
}))
}
/// Returns true if the URL is definitely invalid. For Servo URLs, we can
/// use its |resolved| status.
pub fn is_invalid(&self) -> bool {
self.resolved.is_none()
}
/// Returns true if this URL looks like a fragment.
///
/// Since Servo currently stores resolved URLs, this is hard to implement. We
/// either need to change servo to lazily resolve (like Gecko), or note this
/// information in the tokenizer.
pub fn is_fragment(&self) -> bool {
error!("Can't determine whether the url is a fragment.");
false
}
/// Returns the resolved url if it was valid.
pub fn url(&self) -> Option<&Arc<Url>> {
self.resolved.as_ref()
}
/// Return the resolved url as string, or the empty string if it's invalid.
///
/// TODO(emilio): Should we return the original one if needed?
pub fn as_str(&self) -> &str {
match self.resolved {
Some(ref url) => url.as_str(),
None => "",
}
}
/// Creates an already specified url value from an already resolved URL
/// for insertion in the cascade.
pub fn for_cascade(url: Arc<::url::Url>) -> Self {
CssUrl(Arc::new(CssUrlData {
original: None,
resolved: Some(url),
}))
}
/// Gets a new url from a string for unit tests.
pub fn new_for_testing(url: &str) -> Self {
CssUrl(Arc::new(CssUrlData {
original: Some(Arc::new(url.into())),
resolved: (!url.is_empty())
.then(|| ::url::Url::parse(url))
.and_then(Result::ok)
.map(Arc::new),
}))
}
}
impl PartialEq for CssUrl {
fn eq(&self, other: &Self) -> bool {
// TODO(emilio): maybe we care about equality of the specified values if
// present? Seems not.
self.resolved == other.resolved
}
}
impl Eq for CssUrl {}
impl ToCss for CssUrl {
fn to_css<W>(&self, dest: &mut CssWriter<W>) -> fmt::Result
where
W: Write,
{
let string = match self.0.original {
Some(ref original) => &**original,
None => match self.resolved {
Some(ref url) => url.as_str(),
// This can only happen if the url wasn't specified by the
// user *and* it's an invalid url that has been transformed
// back to specified value via the "uncompute" functionality.
None => "about:invalid",
},
};
dest.write_str("url(")?;
string.to_css(dest)?;
dest.write_char(')')
}
}
/// A specified url() value for servo.
pub type SpecifiedUrl = CssUrl;
impl ToComputedValue for SpecifiedUrl {
type ComputedValue = ComputedUrl;
// If we can't resolve the URL from the specified one, we fall back to the original
// but still return it as a ComputedUrl::Invalid
fn to_computed_value(&self, _: &Context) -> Self::ComputedValue {
match self.resolved {
Some(ref url) => ComputedUrl::Valid(url.clone()),
None => match self.original {
Some(ref url) => ComputedUrl::Invalid(url.clone()),
None => {
unreachable!("Found specified url with neither resolved or original URI!");
},
},
}
}
fn from_computed_value(computed: &ComputedUrl) -> Self {
let data = match *computed {
ComputedUrl::Valid(ref url) => CssUrlData {
original: None,
resolved: Some(url.clone()),
},
ComputedUrl::Invalid(ref url) => CssUrlData {
original: Some(url.clone()),
resolved: None,
},
};
CssUrl(Arc::new(data))
}
}
/// The computed value of a CSS `url()`, resolved relative to the stylesheet URL.
#[derive(Clone, Debug, Deserialize, MallocSizeOf, PartialEq, Serialize)]
pub enum ComputedUrl {
/// The `url()` was invalid or it wasn't specified by the user.
Invalid(#[ignore_malloc_size_of = "Arc"] Arc<String>),
/// The resolved `url()` relative to the stylesheet URL.
Valid(#[ignore_malloc_size_of = "Arc"] Arc<Url>),
}
impl ComputedUrl {
/// Returns the resolved url if it was valid.
pub fn url(&self) -> Option<&Arc<Url>> {
match *self {
ComputedUrl::Valid(ref url) => Some(url),
_ => None,
}
}
}
impl ToCss for ComputedUrl {
fn to_css<W>(&self, dest: &mut CssWriter<W>) -> fmt::Result
where
W: Write,
{
let string = match *self {
ComputedUrl::Valid(ref url) => url.as_str(),
ComputedUrl::Invalid(ref invalid_string) => invalid_string,
};
dest.write_str("url(")?;
string.to_css(dest)?;
dest.write_char(')')
}
}