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use crate::rewritable_units::{Comment, Doctype, DocumentEnd, Element, EndTag, TextChunk}; use crate::selectors_vm::Selector; // N.B. `use crate::` will break this because the constructor is not public, only the struct itself use super::AsciiCompatibleEncoding; use std::borrow::Cow; use std::error::Error; pub(super) type HandlerResult = Result<(), Box<dyn Error + Send + Sync>>; pub type DoctypeHandler<'h> = Box<dyn FnMut(&mut Doctype) -> HandlerResult + 'h>; pub type CommentHandler<'h> = Box<dyn FnMut(&mut Comment) -> HandlerResult + 'h>; pub type TextHandler<'h> = Box<dyn FnMut(&mut TextChunk) -> HandlerResult + 'h>; pub type ElementHandler<'h> = Box<dyn FnMut(&mut Element) -> HandlerResult + 'h>; pub type EndTagHandler<'h> = Box<dyn FnOnce(&mut EndTag) -> HandlerResult + 'h>; pub type EndHandler<'h> = Box<dyn FnOnce(&mut DocumentEnd) -> HandlerResult + 'h>; /// Specifies element content handlers associated with a selector. #[derive(Default)] pub struct ElementContentHandlers<'h> { pub(super) element: Option<ElementHandler<'h>>, pub(super) comments: Option<CommentHandler<'h>>, pub(super) text: Option<TextHandler<'h>>, } impl<'h> ElementContentHandlers<'h> { /// Sets a handler for elements matched by a selector. #[inline] pub fn element(mut self, handler: impl FnMut(&mut Element) -> HandlerResult + 'h) -> Self { self.element = Some(Box::new(handler)); self } /// Sets a handler for HTML comments in the inner content of elements matched by a selector. #[inline] pub fn comments(mut self, handler: impl FnMut(&mut Comment) -> HandlerResult + 'h) -> Self { self.comments = Some(Box::new(handler)); self } /// Sets a handler for text chunks in the inner content of elements matched by a selector. #[inline] pub fn text(mut self, handler: impl FnMut(&mut TextChunk) -> HandlerResult + 'h) -> Self { self.text = Some(Box::new(handler)); self } } /// Specifies document-level content handlers. /// /// Some content can't be captured by CSS selectors as it lays outside of content of any /// of the HTML elements. Document-level handlers allow capture such a content: /// /// ```html /// <!doctype html> /// <!-- /// I can't be captured with a selector, but I can be /// captured with a document-level comment handler /// --> /// <html> /// <!-- I can be captured with a selector --> /// </html> /// ``` #[derive(Default)] pub struct DocumentContentHandlers<'h> { pub(super) doctype: Option<DoctypeHandler<'h>>, pub(super) comments: Option<CommentHandler<'h>>, pub(super) text: Option<TextHandler<'h>>, pub(super) end: Option<EndHandler<'h>>, } impl<'h> DocumentContentHandlers<'h> { /// Sets a handler for the [document type declaration]. /// /// [document type declaration]: https://developer.mozilla.org/en-US/docs/Glossary/Doctype #[inline] pub fn doctype(mut self, handler: impl FnMut(&mut Doctype) -> HandlerResult + 'h) -> Self { self.doctype = Some(Box::new(handler)); self } /// Sets a handler for all HTML comments present in the input HTML markup. #[inline] pub fn comments(mut self, handler: impl FnMut(&mut Comment) -> HandlerResult + 'h) -> Self { self.comments = Some(Box::new(handler)); self } /// Sets a handler for all text chunks present in the input HTML markup. #[inline] pub fn text(mut self, handler: impl FnMut(&mut TextChunk) -> HandlerResult + 'h) -> Self { self.text = Some(Box::new(handler)); self } /// Sets a handler for the document end, which is called after the last chunk is processed. #[inline] pub fn end(mut self, handler: impl FnMut(&mut DocumentEnd) -> HandlerResult + 'h) -> Self { self.end = Some(Box::new(handler)); self } } #[doc(hidden)] #[macro_export] macro_rules! __element_content_handler { ($selector:expr, $handler_name:ident, $handler:expr) => { ( ::std::borrow::Cow::Owned($selector.parse::<$crate::Selector>().unwrap()), $crate::ElementContentHandlers::default().$handler_name($handler), ) }; } /// A convenience macro to construct a rewriting handler for elements that can be matched by the /// specified CSS selector. /// /// # Example /// ``` /// use lol_html::{rewrite_str, element, RewriteStrSettings}; /// use lol_html::html_content::ContentType; /// /// let html = rewrite_str( /// r#"<span id="foo"></span>"#, /// RewriteStrSettings { /// element_content_handlers: vec![ /// element!("#foo", |el| { /// el.set_inner_content("Hello!", ContentType::Text); /// /// Ok(()) /// }) /// ], /// ..RewriteStrSettings::default() /// } /// ).unwrap(); /// /// assert_eq!(html, r#"<span id="foo">Hello!</span>"#); /// ``` #[macro_export(local_inner_macros)] macro_rules! element { ($selector:expr, $handler:expr) => { __element_content_handler!($selector, element, $handler); }; } /// A convenience macro to construct a rewriting handler for text chunks in the inner content of an /// element that can be matched by the specified CSS selector. /// /// # Example /// ``` /// use lol_html::{rewrite_str, text, RewriteStrSettings}; /// use lol_html::html_content::ContentType; /// /// let html = rewrite_str( /// r#"<span>Hello</span>"#, /// RewriteStrSettings { /// element_content_handlers: vec![ /// text!("span", |t| { /// if t.last_in_text_node() { /// t.after(" world", ContentType::Text); /// } /// /// Ok(()) /// }) /// ], /// ..RewriteStrSettings::default() /// } /// ).unwrap(); /// /// assert_eq!(html, r#"<span>Hello world</span>"#); /// ``` #[macro_export(local_inner_macros)] macro_rules! text { ($selector:expr, $handler:expr) => { __element_content_handler!($selector, text, $handler); }; } /// A convenience macro to construct a rewriting handler for HTML comments in the inner content of /// an element that can be matched by the specified CSS selector. /// /// # Example /// ``` /// use lol_html::{rewrite_str, comments, RewriteStrSettings}; /// use lol_html::html_content::ContentType; /// /// let html = rewrite_str( /// r#"<span><!-- 42 --></span>"#, /// RewriteStrSettings { /// element_content_handlers: vec![ /// comments!("span", |c| { /// c.set_text("Hello!").unwrap(); /// /// Ok(()) /// }) /// ], /// ..RewriteStrSettings::default() /// } /// ).unwrap(); /// /// assert_eq!(html, r#"<span><!--Hello!--></span>"#); /// ``` #[macro_export(local_inner_macros)] macro_rules! comments { ($selector:expr, $handler:expr) => { __element_content_handler!($selector, comments, $handler); }; } #[doc(hidden)] #[macro_export] macro_rules! __document_content_handler { ($handler_name:ident, $handler:expr) => { $crate::DocumentContentHandlers::default().$handler_name($handler) }; } /// A convenience macro to construct a handler for [document type declarations] in the HTML document. /// /// # Example /// ``` /// use lol_html::{rewrite_str, doctype, RewriteStrSettings}; /// use lol_html::html_content::ContentType; /// /// rewrite_str( /// r#"<!doctype html>"#, /// RewriteStrSettings { /// document_content_handlers: vec![ /// doctype!(|d| { /// assert_eq!(d.name().unwrap(), "html"); /// /// Ok(()) /// }) /// ], /// ..RewriteStrSettings::default() /// } /// ).unwrap(); /// ``` /// /// [document type declarations]: https://developer.mozilla.org/en-US/docs/Glossary/Doctype #[macro_export(local_inner_macros)] macro_rules! doctype { ($handler:expr) => { __document_content_handler!(doctype, $handler); }; } /// A convenience macro to construct a rewriting handler for all text chunks in the HTML document. /// /// # Example /// ``` /// use lol_html::{rewrite_str, doc_text, RewriteStrSettings}; /// use lol_html::html_content::ContentType; /// /// let html = rewrite_str( /// r#"Hello<span>Hello</span>Hello"#, /// RewriteStrSettings { /// document_content_handlers: vec![ /// doc_text!(|t| { /// if t.last_in_text_node() { /// t.after(" world", ContentType::Text); /// } /// /// Ok(()) /// }) /// ], /// ..RewriteStrSettings::default() /// } /// ).unwrap(); /// /// assert_eq!(html, r#"Hello world<span>Hello world</span>Hello world"#); /// ``` #[macro_export(local_inner_macros)] macro_rules! doc_text { ($handler:expr) => { __document_content_handler!(text, $handler); }; } /// A convenience macro to construct a rewriting handler for all HTML comments in the HTML document. /// /// # Example /// ``` /// use lol_html::{rewrite_str, doc_comments, RewriteStrSettings}; /// use lol_html::html_content::ContentType; /// /// let html = rewrite_str( /// r#"<!-- 42 --><span><!-- 42 --></span><!-- 42 -->"#, /// RewriteStrSettings { /// document_content_handlers: vec![ /// doc_comments!(|c| { /// c.set_text("Hello!").unwrap(); /// /// Ok(()) /// }) /// ], /// ..RewriteStrSettings::default() /// } /// ).unwrap(); /// /// assert_eq!(html, r#"<!--Hello!--><span><!--Hello!--></span><!--Hello!-->"#); /// ``` #[macro_export(local_inner_macros)] macro_rules! doc_comments { ($handler:expr) => { __document_content_handler!(comments, $handler); }; } /// A convenience macro to construct a rewriting handler for the end of the document. /// /// This handler will only be called after the rewriter has finished processing the final chunk. /// /// # Example /// ``` /// use lol_html::{rewrite_str, element, end, RewriteStrSettings}; /// use lol_html::html_content::ContentType; /// /// let html = rewrite_str( /// r#"<span>foo</span>"#, /// RewriteStrSettings { /// element_content_handlers: vec![ /// element!("span", |el| { /// el.append("bar", ContentType::Text); /// /// Ok(()) /// }) /// ], /// document_content_handlers: vec![ /// end!(|end| { /// end.append("<div>baz</div>", ContentType::Html); /// /// Ok(()) /// }) /// ], /// ..RewriteStrSettings::default() /// } /// ).unwrap(); /// /// assert_eq!(html, r#"<span>foobar</span><div>baz</div>"#); /// ``` #[macro_export(local_inner_macros)] macro_rules! end { ($handler:expr) => { __document_content_handler!(end, $handler); }; } /// Specifies the memory settings for [`HtmlRewriter`]. /// /// [`HtmlRewriter`]: struct.HtmlRewriter.html // NOTE: exposed in C API as well, thus repr(C). #[repr(C)] pub struct MemorySettings { /// Specifies the number of bytes that should be preallocated on [`HtmlRewriter`] instantiation /// for the internal parsing buffer. /// /// In some cases (e.g. when rewriter encounters a start tag represented by two or more input /// chunks) the rewriter needs to buffer input content. /// /// Internal parsing buffer is used in such cases. Reallocations and, thus, performance /// degradation can be avoided by preallocating the buffer ahead of time. As a drawback of /// this approach, every instance of the rewriter will consume the preallocated amount of /// memory. /// /// It's up to the user to adjust the limit according to their environment limitations. /// /// ### Default /// /// `1024` bytes when constructed with `MemorySettings::default()`. /// /// [`HtmlRewriter`]: struct.HtmlRewriter.html pub preallocated_parsing_buffer_size: usize, /// Sets a hard limit in bytes on memory consumption of a [`HtmlRewriter`] instance. /// /// Rewriter's [`write`] and [`end`] methods will error if this limit is exceeded. /// /// Note, that value doesn't reflect the exact threshold after which the rewriter will bailout. /// It is impossible to account for all the memory consumed without a significant performance /// penalty. So, instead, we try to provide the best approximation by measuring the memory /// consumed by internal buffers that grow depending on the input. /// /// ### Default /// /// [`std::usize::MAX`] when constructed with `MemorySettings::default()`. /// /// [`HtmlRewriter`]: struct.HtmlRewriter.html /// [`std::usize::MAX`]: https://doc.rust-lang.org/std/usize/constant.MAX.html /// [`write`]: struct.HtmlRewriter.html#method.write /// [`end`]: struct.HtmlRewriter.html#method.end pub max_allowed_memory_usage: usize, } impl Default for MemorySettings { #[inline] fn default() -> Self { MemorySettings { preallocated_parsing_buffer_size: 1024, max_allowed_memory_usage: std::usize::MAX, } } } /// Specifies settings for [`HtmlRewriter`]. /// /// [`HtmlRewriter`]: struct.HtmlRewriter.html pub struct Settings<'h, 's> { /// Specifies CSS selectors and rewriting handlers for elements and their inner content. /// /// ### Hint /// /// [`element`], [`comments`] and [`text`] convenience macros can be used to construct a /// `(Selector, ElementContentHandlers)` tuple. /// /// ### Example /// ``` /// use std::borrow::Cow; /// use lol_html::{ElementContentHandlers, Settings}; /// /// let settings = Settings { /// element_content_handlers: vec! [ /// ( /// Cow::Owned("div[foo]".parse().unwrap()), /// ElementContentHandlers::default().element(|el| { /// // ... /// /// Ok(()) /// }) /// ), /// ( /// Cow::Owned("body".parse().unwrap()), /// ElementContentHandlers::default().comments(|c| { /// // ... /// /// Ok(()) /// }) /// ) /// ], /// ..Settings::default() /// }; /// ``` /// /// [`element`]: macro.element.html /// [`comments`]: macro.comments.html /// [`text`]: macro.text.html pub element_content_handlers: Vec<(Cow<'s, Selector>, ElementContentHandlers<'h>)>, /// Specifies rewriting handlers for the content without associating it to a particular /// CSS selector. /// /// Refer to [`DocumentContentHandlers`] documentation for more information. /// /// ### Hint /// [`doctype`], [`doc_comments`] and [`doc_text`] convenience macros can be used to construct /// items of this vector. /// /// [`DocumentContentHandlers`]: struct.DocumentContentHandlers.html /// [`doctype`]: macro.doctype.html /// [`doc_comments`]: macro.doc_comments.html /// [`doc_text`]: macro.doc_text.html pub document_content_handlers: Vec<DocumentContentHandlers<'h>>, /// Specifies the [character encoding] for the input and the output of the rewriter. /// /// Can be a [label] for any of the web-compatible encodings with an exception for `UTF-16LE`, /// `UTF-16BE`, `ISO-2022-JP` and `replacement` (these non-ASCII-compatible encodings /// are not supported). /// /// [character encoding]: https://developer.mozilla.org/en-US/docs/Glossary/character_encoding /// [label]: https://encoding.spec.whatwg.org/#names-and-labels /// /// ### Default /// /// `"utf-8"` when constructed with `Settings::default()`. pub encoding: AsciiCompatibleEncoding, /// Specifies the memory settings. pub memory_settings: MemorySettings, /// If set to `true` the rewriter bails out if it encounters markup that drives the HTML parser /// into ambigious state. /// /// Since the rewriter operates on a token stream and doesn't have access to a full /// DOM-tree, there are certain rare cases of non-conforming HTML markup which can't be /// guaranteed to be parsed correctly without an ability to backtrace the tree. /// /// Therefore, due to security considerations, sometimes it's preferable to abort the /// rewriting process in case of such uncertainty. /// /// One of the simplest examples of such markup is the following: /// /// ```html /// ... /// <select><xmp><script>"use strict";</script></select> /// ... /// ``` /// /// The `<xmp>` element is not allowed inside the `<select>` element, so in a browser the start /// tag for `<xmp>` will be ignored and following `<script>` element will be parsed and executed. /// /// On the other hand, the `<select>` element itself can be also ignored depending on the /// context in which it was parsed. In this case, the `<xmp>` element will not be ignored /// and the `<script>` element along with its content will be parsed as a simple text inside /// it. /// /// So, in this case the parser needs an ability to backtrace the DOM-tree to figure out the /// correct parsing context. /// /// ### Default /// /// `true` when constructed with `Settings::default()`. pub strict: bool, } impl Default for Settings<'_, '_> { #[inline] fn default() -> Self { Settings { element_content_handlers: vec![], document_content_handlers: vec![], encoding: AsciiCompatibleEncoding(encoding_rs::UTF_8), memory_settings: MemorySettings::default(), strict: true, } } } impl<'h, 's> From<RewriteStrSettings<'h, 's>> for Settings<'h, 's> { #[inline] fn from(settings: RewriteStrSettings<'h, 's>) -> Self { Settings { element_content_handlers: settings.element_content_handlers, document_content_handlers: settings.document_content_handlers, strict: settings.strict, ..Settings::default() } } } /// Specifies settings for the [`rewrite_str`] function. /// /// [`rewrite_str`]: fn.rewrite_str.html pub struct RewriteStrSettings<'h, 's> { /// Specifies CSS selectors and rewriting handlers for elements and their inner content. /// /// ### Hint /// /// [`element`], [`comments`] and [`text`] convenience macros can be used to construct a /// `(Selector, ElementContentHandlers)` tuple. /// /// ### Example /// ``` /// use std::borrow::Cow; /// use lol_html::{ElementContentHandlers, RewriteStrSettings}; /// /// let settings = RewriteStrSettings { /// element_content_handlers: vec! [ /// ( /// Cow::Owned("div[foo]".parse().unwrap()), /// ElementContentHandlers::default().element(|el| { /// // ... /// /// Ok(()) /// }) /// ), /// ( /// Cow::Owned("div[foo]".parse().unwrap()), /// ElementContentHandlers::default().comments(|c| { /// // ... /// /// Ok(()) /// }) /// ) /// ], /// ..RewriteStrSettings::default() /// }; /// ``` /// /// [`element`]: macro.element.html /// [`comments`]: macro.comments.html /// [`text`]: macro.text.html pub element_content_handlers: Vec<(Cow<'s, Selector>, ElementContentHandlers<'h>)>, /// Specifies rewriting handlers for the content without associating it to a particular /// CSS selector. /// /// Refer to [`DocumentContentHandlers`] documentation for more information. /// /// ### Hint /// [`doctype`], [`doc_comments`] and [`doc_text`] convenience macros can be used to construct /// items of this vector. /// /// [`DocumentContentHandlers`]: struct.DocumentContentHandlers.html /// [`doctype`]: macro.doctype.html /// [`doc_comments`]: macro.doc_comments.html /// [`doc_text`]: macro.doc_text.html pub document_content_handlers: Vec<DocumentContentHandlers<'h>>, /// If set to `true` the rewriter bails out if it encounters markup that drives the HTML parser /// into ambigious state. /// /// Since the rewriter operates on a token stream and doesn't have access to a full /// DOM-tree, there are certain rare cases of non-conforming HTML markup which can't be /// guaranteed to be parsed correctly without an ability to backtrace the tree. /// /// Therefore, due to security considerations, sometimes it's preferable to abort the /// rewriting process in case of such uncertainty. /// /// One of the simplest examples of such markup is the following: /// /// ```html /// ... /// <select><xmp><script>"use strict";</script></select> /// ... /// ``` /// /// The `<xmp>` element is not allowed inside the `<select>` element, so in a browser the start /// tag for `<xmp>` will be ignored and following `<script>` element will be parsed and executed. /// /// On the other hand, the `<select>` element itself can be also ignored depending on the /// context in which it was parsed. In this case, the `<xmp>` element will not be ignored /// and the `<script>` element along with its content will be parsed as a simple text inside /// it. /// /// So, in this case the parser needs an ability to backtrace the DOM-tree to figure out the /// correct parsing context. /// /// ### Default /// /// `true` when constructed with `Settings::default()`. pub strict: bool, } impl Default for RewriteStrSettings<'_, '_> { #[inline] fn default() -> Self { RewriteStrSettings { element_content_handlers: vec![], document_content_handlers: vec![], strict: true, } } }