Store mutations as text chunks

cloudflare · Oct 28, 2024 · e7c7ebe · e7c7ebe
1 parent 54af4e1
commit e7c7ebe
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Showing 9 changed files with 159 additions and 81 deletions.
diff --git a/src/lib.rs b/src/lib.rs
@@ -201,7 +201,7 @@ cfg_if! {
         };
 
         pub use self::rewritable_units::{
-            EndTag, Serialize, StartTag, Token, TokenCaptureFlags, Mutations
+            EndTag, Serialize, StartTag, Token, TokenCaptureFlags,
         };
 
         pub use self::memory::SharedMemoryLimiter;

diff --git a/src/rewritable_units/element.rs b/src/rewritable_units/element.rs
@@ -1,4 +1,4 @@
-use super::{Attribute, AttributeNameError, ContentType, EndTag, Mutations, StartTag};
+use super::{Attribute, AttributeNameError, ContentType, EndTag, Mutations, StartTag, StringChunk};
 use crate::base::Bytes;
 use crate::rewriter::{HandlerTypes, LocalHandlerTypes};
 use encoding_rs::Encoding;
@@ -87,7 +87,9 @@ impl<'r, 't, H: HandlerTypes> Element<'r, 't, H> {
     #[inline]
     fn remove_content(&mut self) {
         self.start_tag.mutations.content_after.clear();
-        self.end_tag_mutations_mut().content_before.clear();
+        if let Some(end) = &mut self.end_tag_mutations {
+            end.content_before.clear();
+        }
         self.should_remove_content = true;
     }
 
@@ -222,7 +224,10 @@ impl<'r, 't, H: HandlerTypes> Element<'r, 't, H> {
     /// ```
     #[inline]
     pub fn before(&mut self, content: &str, content_type: ContentType) {
-        self.start_tag.mutations.before(content, content_type);
+        self.start_tag
+            .mutations
+            .content_before
+            .push_back((content, content_type).into());
     }
 
     /// Inserts `content` after the element.
@@ -255,11 +260,16 @@ impl<'r, 't, H: HandlerTypes> Element<'r, 't, H> {
     /// ```
     #[inline]
     pub fn after(&mut self, content: &str, content_type: ContentType) {
+        self.after_chunk((content, content_type).into());
+    }
+
+    fn after_chunk(&mut self, chunk: StringChunk) {
         if self.can_have_content {
-            self.end_tag_mutations_mut().after(content, content_type);
+            &mut self.end_tag_mutations_mut().content_after
         } else {
-            self.start_tag.mutations.after(content, content_type);
+            &mut self.start_tag.mutations.content_after
         }
+        .push_front(chunk);
     }
 
     /// Prepends `content` to the element's inner content, i.e. inserts content right after
@@ -299,8 +309,12 @@ impl<'r, 't, H: HandlerTypes> Element<'r, 't, H> {
     /// ```
     #[inline]
     pub fn prepend(&mut self, content: &str, content_type: ContentType) {
+        self.prepend_chunk((content, content_type).into());
+    }
+
+    fn prepend_chunk(&mut self, chunk: StringChunk) {
         if self.can_have_content {
-            self.start_tag.mutations.after(content, content_type);
+            self.start_tag.mutations.content_after.push_front(chunk);
         }
     }
 
@@ -341,8 +355,12 @@ impl<'r, 't, H: HandlerTypes> Element<'r, 't, H> {
     /// ```
     #[inline]
     pub fn append(&mut self, content: &str, content_type: ContentType) {
+        self.append_chunk((content, content_type).into());
+    }
+
+    fn append_chunk(&mut self, chunk: StringChunk) {
         if self.can_have_content {
-            self.end_tag_mutations_mut().before(content, content_type);
+            self.end_tag_mutations_mut().content_before.push_back(chunk);
         }
     }
 
@@ -382,9 +400,13 @@ impl<'r, 't, H: HandlerTypes> Element<'r, 't, H> {
     /// ```
     #[inline]
     pub fn set_inner_content(&mut self, content: &str, content_type: ContentType) {
+        self.set_inner_content_chunk((content, content_type).into());
+    }
+
+    fn set_inner_content_chunk(&mut self, chunk: StringChunk) {
         if self.can_have_content {
             self.remove_content();
-            self.start_tag.mutations.after(content, content_type);
+            self.start_tag.mutations.content_after.push_front(chunk);
         }
     }
 
@@ -417,7 +439,11 @@ impl<'r, 't, H: HandlerTypes> Element<'r, 't, H> {
     /// ```
     #[inline]
     pub fn replace(&mut self, content: &str, content_type: ContentType) {
-        self.start_tag.mutations.replace(content, content_type);
+        self.replace_chunk((content, content_type).into());
+    }
+
+    fn replace_chunk(&mut self, chunk: StringChunk) {
+        self.start_tag.mutations.replace(chunk);
 
         if self.can_have_content {
             self.remove_content();

diff --git a/src/rewritable_units/mod.rs b/src/rewritable_units/mod.rs
@@ -2,7 +2,8 @@ use std::any::Any;
 
 pub use self::document_end::*;
 pub use self::element::*;
-pub use self::mutations::{ContentType, Mutations};
+pub use self::mutations::ContentType;
+pub(crate) use self::mutations::{Mutations, StringChunk};
 pub use self::tokens::*;
 
 /// Data that can be attached to a rewritable unit by a user and shared between content handler

diff --git a/src/rewritable_units/mutations.rs b/src/rewritable_units/mutations.rs
@@ -1,7 +1,11 @@
 use crate::base::Bytes;
 use encoding_rs::Encoding;
+use std::error::Error as StdError;
+
+type BoxResult = Result<(), Box<dyn StdError + Send + Sync>>;
 
 /// The type of inserted content.
+#[derive(Copy, Clone)]
 pub enum ContentType {
     /// HTML content type. The rewriter will insert the content as is.
     Html,
@@ -17,7 +21,7 @@ pub(super) fn content_to_bytes(
     content: &str,
     content_type: ContentType,
     encoding: &'static Encoding,
-    mut output_handler: &mut dyn FnMut(&[u8]),
+    output_handler: &mut dyn FnMut(&[u8]),
 ) {
     let bytes = Bytes::from_str(content, encoding);
 
@@ -27,68 +31,99 @@ pub(super) fn content_to_bytes(
             (b'<', b"&lt;"),
             (b'>', b"&gt;"),
             (b'&', b"&amp;"),
-            &mut output_handler,
+            &mut *output_handler,
         ),
     }
 }
 
-pub struct Mutations {
-    pub content_before: Vec<u8>,
-    pub replacement: Vec<u8>,
-    pub content_after: Vec<u8>,
+pub(crate) struct Mutations {
+    pub content_before: DynamicString,
+    pub replacement: DynamicString,
+    pub content_after: DynamicString,
     pub removed: bool,
-    encoding: &'static Encoding,
+    pub encoding: &'static Encoding,
 }
 
 impl Mutations {
     #[inline]
-    pub fn new(encoding: &'static Encoding) -> Self {
-        Mutations {
-            content_before: Vec::default(),
-            replacement: Vec::default(),
-            content_after: Vec::default(),
+    #[must_use]
+    pub const fn new(encoding: &'static Encoding) -> Self {
+        Self {
+            content_before: DynamicString::new(),
+            replacement: DynamicString::new(),
+            content_after: DynamicString::new(),
             removed: false,
             encoding,
         }
     }
 
     #[inline]
-    pub fn before(&mut self, content: &str, content_type: ContentType) {
-        content_to_bytes(content, content_type, self.encoding, &mut |c| {
-            self.content_before.extend_from_slice(c);
-        });
+    pub fn replace(&mut self, chunk: StringChunk) {
+        self.remove();
+        self.replacement.clear();
+        self.replacement.push_back(chunk);
     }
 
     #[inline]
-    pub fn after(&mut self, content: &str, content_type: ContentType) {
-        let mut pos = 0;
-
-        content_to_bytes(content, content_type, self.encoding, &mut |c| {
-            self.content_after.splice(pos..pos, c.iter().cloned());
+    pub fn remove(&mut self) {
+        self.removed = true;
+    }
 
-            pos += c.len();
-        });
+    #[inline]
+    pub const fn removed(&self) -> bool {
+        self.removed
     }
+}
 
+impl From<(&str, ContentType)> for StringChunk {
     #[inline]
-    pub fn replace(&mut self, content: &str, content_type: ContentType) {
-        let mut replacement = Vec::default();
+    fn from((content, content_type): (&str, ContentType)) -> Self {
+        Self::Buffer(Box::from(content), content_type)
+    }
+}
+
+pub(crate) enum StringChunk {
+    Buffer(Box<str>, ContentType),
+}
 
-        content_to_bytes(content, content_type, self.encoding, &mut |c| {
-            replacement.extend_from_slice(c);
-        });
+#[derive(Default)]
+pub(crate) struct DynamicString {
+    chunks: Vec<StringChunk>,
+}
 
-        self.replacement = replacement;
-        self.remove();
+impl DynamicString {
+    #[inline]
+    pub const fn new() -> Self {
+        Self { chunks: vec![] }
     }
 
     #[inline]
-    pub fn remove(&mut self) {
-        self.removed = true;
+    pub fn clear(&mut self) {
+        self.chunks.clear();
     }
 
     #[inline]
-    pub fn removed(&self) -> bool {
-        self.removed
+    pub fn push_front(&mut self, chunk: StringChunk) {
+        self.chunks.insert(0, chunk);
+    }
+
+    #[inline]
+    pub fn push_back(&mut self, chunk: StringChunk) {
+        self.chunks.push(chunk);
+    }
+
+    pub fn into_bytes(
+        self,
+        encoding: &'static Encoding,
+        output_handler: &mut dyn FnMut(&[u8]),
+    ) -> BoxResult {
+        for chunk in self.chunks {
+            match chunk {
+                StringChunk::Buffer(content, content_type) => {
+                    content_to_bytes(&content, content_type, encoding, output_handler);
+                }
+            };
+        }
+        Ok(())
     }
 }
diff --git a/src/rewritable_units/tokens/comment.rs b/src/rewritable_units/tokens/comment.rs
@@ -103,7 +103,9 @@ impl<'i> Comment<'i> {
     /// ```
     #[inline]
     pub fn before(&mut self, content: &str, content_type: crate::rewritable_units::ContentType) {
-        self.mutations.before(content, content_type);
+        self.mutations
+            .content_before
+            .push_back((content, content_type).into());
     }
 
     /// Inserts `content` after the comment.
@@ -135,7 +137,9 @@ impl<'i> Comment<'i> {
     /// ```
     #[inline]
     pub fn after(&mut self, content: &str, content_type: crate::rewritable_units::ContentType) {
-        self.mutations.after(content, content_type);
+        self.mutations
+            .content_after
+            .push_front((content, content_type).into());
     }
 
     /// Replaces the comment with the `content`.
@@ -167,7 +171,7 @@ impl<'i> Comment<'i> {
     /// ```
     #[inline]
     pub fn replace(&mut self, content: &str, content_type: crate::rewritable_units::ContentType) {
-        self.mutations.replace(content, content_type);
+        self.mutations.replace((content, content_type).into());
     }
 
     /// Removes the comment.

diff --git a/src/rewritable_units/tokens/end_tag.rs b/src/rewritable_units/tokens/end_tag.rs
@@ -1,7 +1,7 @@
 use super::{Mutations, Token};
 use crate::base::Bytes;
 use crate::errors::RewritingError;
-use crate::rewritable_units::ContentType;
+use crate::html_content::ContentType;
 use encoding_rs::Encoding;
 use std::fmt::{self, Debug};
 
@@ -59,23 +59,27 @@ impl<'i> EndTag<'i> {
     /// Consequent calls to the method append `content` to the previously inserted content.
     #[inline]
     pub fn before(&mut self, content: &str, content_type: ContentType) {
-        self.mutations.before(content, content_type);
+        self.mutations
+            .content_before
+            .push_back((content, content_type).into());
     }
 
     /// Inserts `content` after the end tag.
     ///
     /// Consequent calls to the method prepend `content` to the previously inserted content.
     #[inline]
     pub fn after(&mut self, content: &str, content_type: ContentType) {
-        self.mutations.after(content, content_type);
+        self.mutations
+            .content_after
+            .push_front((content, content_type).into());
     }
 
     /// Replaces the end tag with `content`.
     ///
     /// Consequent calls to the method overwrite previous replacement content.
     #[inline]
     pub fn replace(&mut self, content: &str, content_type: ContentType) {
-        self.mutations.replace(content, content_type);
+        self.mutations.replace((content, content_type).into());
     }
 
     /// Removes the end tag.

diff --git a/src/rewritable_units/tokens/mod.rs b/src/rewritable_units/tokens/mod.rs
@@ -16,32 +16,31 @@ macro_rules! impl_serialize {
     ($Token:ident) => {
         impl crate::rewritable_units::Serialize for $Token<'_> {
             #[inline]
-            fn into_bytes(self, output_handler: &mut dyn FnMut(&[u8])) -> Result<(), RewritingError> {
-                let Mutations {
-                    content_before,
-                    replacement,
-                    content_after,
-                    removed,
-                    ..
-                } = &self.mutations;
+            fn into_bytes(
+                mut self,
+                output_handler: &mut dyn FnMut(&[u8]),
+            ) -> Result<(), crate::errors::RewritingError> {
+                let content_before = ::std::mem::take(&mut self.mutations.content_before);
+                content_before
+                    .into_bytes(self.mutations.encoding, output_handler)
+                    .map_err(crate::errors::RewritingError::ContentHandlerError)?;
 
-                if !content_before.is_empty() {
-                    output_handler(content_before);
-                }
-
-                if !removed {
+                if !self.mutations.removed {
                     match self.raw() {
                         Some(raw) => output_handler(raw),
                         None => self.serialize_from_parts(output_handler)?,
                     }
-                } else if !replacement.is_empty() {
-                    output_handler(replacement);
+                } else {
+                    self.mutations
+                        .replacement
+                        .into_bytes(self.mutations.encoding, output_handler)
+                        .map_err(crate::errors::RewritingError::ContentHandlerError)?;
                 }
 
-                if !content_after.is_empty() {
-                    output_handler(content_after);
-                }
-                Ok(())
+                self.mutations
+                    .content_after
+                    .into_bytes(self.mutations.encoding, output_handler)
+                    .map_err(crate::errors::RewritingError::ContentHandlerError)
             }
         }
     };