mirror of https://github.com/boa-dev/boa.git
Browse Source
* feat: add `JsStringBuilder` and test * chore: fix calculation on capacity and add `clone` impl * chore: some misc fix * fix: wrong capacity calculation in `extend` * chore: prevent `reserve` except for the shrink in `build` * chore: fix misc * perf: use `realloc` for allocation * chore: fix lint * fix: wrong ascii validation * fix: wrong allocated data bytes calculation * fix: wrong capacity calcultion on `with_capacity` * fix: clippy fix * chore: add public `reserve` * chore: comments and renaming * chore: update misc * chore: moved to module `builder` and implement `AddAssign` for `Builder` * chore: add zero case for `with_capacity` * chore: mark public methods `inline` * chore: extract allocation check into `allocate_if_needed` * chore: fix lint * chore: expose `JsStringData` * feat: add common string builder and export 1 byte and 2 bytes string builder * chore: add missed trait * chore: fix lint * chore: fix doc * chore: add `reserve_exact` * chore: typos * chore: fix argument * chore: fix doc * chore: mark `current_layout` unsafe * chore: fix lint * chore: remove `JsStringData` and rename builders * chore: add build methods to typed builders * chore: add more build methods to `CommonJsStringBuilder` * chore: rename `latin1` check to `ascii` check * chore: refine docs * chore: update tests * chore: limit the generic type `D` of `JsStringBuilder` to Copy * chore: move `entend` method under `Extend` trait * chore: should validate `Latin1` segement in `build_from_latin1` * chore: add `Add` trait implementation to builders * chore: refines docs and add `inline` to trait methods * chore: adds `clone_from` and related tests * chore: adds `as_mut_slice` to typed builderspull/4052/head
CrazyboyQCD
4 days ago
committed by
GitHub
3 changed files with 1137 additions and 1 deletions
@ -0,0 +1,915 @@
|
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use crate::{ |
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alloc_overflow, tagged::Tagged, JsStr, JsStrVariant, JsString, RawJsString, RefCount, |
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TaggedLen, DATA_OFFSET, |
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}; |
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|
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use std::{ |
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alloc::{alloc, dealloc, realloc, Layout}, |
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cell::Cell, |
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marker::PhantomData, |
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mem::ManuallyDrop, |
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ops::{Add, AddAssign}, |
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ptr::{self, addr_of_mut, NonNull}, |
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str::{self}, |
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}; |
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|
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/// A mutable builder to create instance of `JsString`.
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///
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#[derive(Debug)] |
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pub struct JsStringBuilder<D: Copy> { |
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cap: usize, |
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len: usize, |
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inner: NonNull<RawJsString>, |
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phantom_data: PhantomData<D>, |
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} |
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|
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impl<D: Copy> Default for JsStringBuilder<D> { |
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fn default() -> Self { |
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Self::new() |
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} |
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} |
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|
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impl<D: Copy> JsStringBuilder<D> { |
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const DATA_SIZE: usize = size_of::<D>(); |
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const MIN_NON_ZERO_CAP: usize = 8 / Self::DATA_SIZE; |
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|
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/// Create a new `JsStringBuilder` with capacity of zero.
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#[inline] |
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#[must_use] |
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pub const fn new() -> Self { |
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Self { |
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cap: 0, |
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len: 0, |
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inner: NonNull::dangling(), |
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phantom_data: PhantomData, |
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} |
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} |
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/// Returns the number of elements that inner `RawJsString` holds.
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#[inline] |
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#[must_use] |
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pub const fn len(&self) -> usize { |
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self.len |
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} |
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|
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/// Forces the length of the [`JsStringBuilder`] to `new_len`.
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///
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/// # Safety
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///
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/// - `new_len` must be less than or equal to `capacity()`.
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/// - The elements at `old_len..new_len` must be initialized.
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///
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#[inline] |
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pub unsafe fn set_len(&mut self, new_len: usize) { |
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debug_assert!(new_len <= self.capacity()); |
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self.len = new_len; |
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} |
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|
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/// Returns the total number of elements can hold without reallocating
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#[inline] |
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#[must_use] |
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pub const fn capacity(&self) -> usize { |
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self.cap |
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} |
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|
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/// Returns the allocated byte of inner `RawJsString`'s data.
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#[must_use] |
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const fn allocated_data_byte_len(&self) -> usize { |
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self.len() * Self::DATA_SIZE |
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} |
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|
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/// Returns the capacity calculated from given layout.
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#[must_use] |
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const fn capacity_from_layout(layout: Layout) -> usize { |
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(layout.size() - DATA_OFFSET) / Self::DATA_SIZE |
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} |
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|
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/// Create a new `JsStringBuilder` with specific capacity
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#[inline] |
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#[must_use] |
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pub fn with_capacity(cap: usize) -> Self { |
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if cap == 0 { |
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return Self::new(); |
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} |
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let layout = Self::new_layout(cap); |
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#[allow(clippy::cast_ptr_alignment)] |
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// SAFETY:
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// The layout size of `RawJsString` is never zero, since it has to store
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// the length of the string and the reference count.
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let ptr = unsafe { alloc(layout) }; |
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|
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let Some(ptr) = NonNull::new(ptr.cast()) else { |
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std::alloc::handle_alloc_error(layout) |
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}; |
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Self { |
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cap: Self::capacity_from_layout(layout), |
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len: 0, |
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inner: ptr, |
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phantom_data: PhantomData, |
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} |
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} |
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|
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/// Checks if the inner `RawJsString` is allocated.
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#[must_use] |
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fn is_allocated(&self) -> bool { |
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self.inner != NonNull::dangling() |
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} |
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|
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/// Returns the inner `RawJsString`'s layout.
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///
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/// # Safety
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///
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/// Caller should ensure that the inner is allocated.
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#[must_use] |
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unsafe fn current_layout(&self) -> Layout { |
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// SAFETY:
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// Caller should ensure that the inner is allocated.
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unsafe { |
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Layout::for_value(self.inner.as_ref()) |
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.extend(Layout::array::<D>(self.capacity()).unwrap_unchecked()) |
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.unwrap_unchecked() |
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.0 |
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.pad_to_align() |
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} |
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} |
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|
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/// Returns the pointer of `data` of inner.
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///
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/// # Safety
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///
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/// Caller should ensure that the inner is allocated.
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#[must_use] |
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unsafe fn data(&self) -> *mut D { |
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// SAFETY:
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// Caller should ensure that the inner is allocated.
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unsafe { addr_of_mut!((*self.inner.as_ptr()).data).cast() } |
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} |
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|
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/// Allocates when there is not sufficient capacity.
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#[allow(clippy::inline_always)] |
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#[inline(always)] |
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fn allocate_if_needed(&mut self, reuired_cap: usize) { |
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if reuired_cap > self.capacity() { |
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self.allocate(reuired_cap); |
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} |
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} |
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|
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/// Inner logic of `allocate`.
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///
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/// Use `realloc` here because it has a better performance than using combination of `alloc`, `copy` and `dealloc`.
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#[allow(clippy::cast_ptr_alignment)] |
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fn allocate_inner(&mut self, new_layout: Layout) { |
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let new_ptr = if self.is_allocated() { |
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let old_ptr = self.inner.as_ptr(); |
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// SAFETY:
|
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// Allocation check has been made above.
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let old_layout = unsafe { self.current_layout() }; |
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// SAFETY:
|
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// Valid pointer is required by `realloc` and pointer is checked above to be valid.
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// The layout size of `RawJsString` is never zero, since it has to store
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// the length of the string and the reference count.
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unsafe { realloc(old_ptr.cast(), old_layout, new_layout.size()) } |
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} else { |
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// SAFETY:
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// The layout size of `RawJsString` is never zero, since it has to store
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// the length of the string and the reference count.
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unsafe { alloc(new_layout) } |
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}; |
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let Some(new_ptr) = NonNull::new(new_ptr.cast::<RawJsString>()) else { |
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std::alloc::handle_alloc_error(new_layout) |
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}; |
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self.inner = new_ptr; |
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self.cap = Self::capacity_from_layout(new_layout); |
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} |
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/// Appends an element to the inner `RawJsString` of `JsStringBuilder`.
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#[inline] |
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pub fn push(&mut self, v: D) { |
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let required_cap = self.len() + 1; |
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self.allocate_if_needed(required_cap); |
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// SAFETY:
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// Capacity has been expanded to be large enough to hold elements.
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unsafe { |
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self.push_unchecked(v); |
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} |
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} |
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|
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/// Pushes elements from slice to `JsStringBuilder` without doing capacity check.
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///
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/// Unlike the standard vector, our holded element types are only `u8` and `u16`, which is [`Copy`] derived,
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///
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/// so we only need to copy them instead of cloning.
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///
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/// # Safety
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///
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/// Caller should ensure the capacity is large enough to hold elements.
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#[inline] |
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pub unsafe fn extend_from_slice_unchecked(&mut self, v: &[D]) { |
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// SAFETY: Caller should ensure the capacity is large enough to hold elements.
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unsafe { |
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ptr::copy_nonoverlapping(v.as_ptr(), self.data().add(self.len()), v.len()); |
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} |
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self.len += v.len(); |
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} |
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|
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/// Pushes elements from slice to `JsStringBuilder`.
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#[inline] |
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pub fn extend_from_slice(&mut self, v: &[D]) { |
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let required_cap = self.len() + v.len(); |
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self.allocate_if_needed(required_cap); |
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// SAFETY:
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// Capacity has been expanded to be large enough to hold elements.
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unsafe { |
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self.extend_from_slice_unchecked(v); |
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} |
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} |
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|
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fn new_layout(cap: usize) -> Layout { |
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let new_layout = Layout::array::<D>(cap) |
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.and_then(|arr| Layout::new::<RawJsString>().extend(arr)) |
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.map(|(layout, offset)| (layout.pad_to_align(), offset)) |
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.map_err(|_| None); |
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match new_layout { |
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Ok((new_layout, offset)) => { |
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debug_assert_eq!(offset, DATA_OFFSET); |
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new_layout |
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} |
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Err(None) => alloc_overflow(), |
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Err(Some(layout)) => std::alloc::handle_alloc_error(layout), |
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} |
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} |
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/// Similar to [`Vec::reserve`]
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///
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/// Reserves capacity for at least `additional` more elements to be inserted
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/// in the given `JsStringBuilder<D>`. The collection may reserve more space to
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/// speculatively avoid frequent reallocations. After calling `reserve`,
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/// capacity will be greater than or equal to `self.len() + additional`.
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/// Does nothing if capacity is already sufficient.
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#[inline] |
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pub fn reserve(&mut self, additional: usize) { |
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if additional > self.capacity().wrapping_sub(self.len) { |
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let Some(cap) = self.len().checked_add(additional) else { |
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alloc_overflow() |
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}; |
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self.allocate(cap); |
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} |
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} |
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|
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/// Similar to [`Vec::reserve_exact`]
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///
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/// Reserves the minimum capacity for at least `additional` more elements to
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/// be inserted in the given `JsStringBuilder<D>`. Unlike [`reserve`], this will not
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/// deliberately over-allocate to speculatively avoid frequent allocations.
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/// After calling `reserve_exact`, capacity will be greater than or equal to
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/// `self.len() + additional`. Does nothing if the capacity is already
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/// sufficient.
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///
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/// Note that the allocator may give the collection more space than it
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/// requests. Therefore, capacity can not be relied upon to be precisely
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/// minimal. Prefer [`reserve`] if future insertions are expected.
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///
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/// [`reserve`]: JsStringBuilder::reserve
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#[inline] |
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pub fn reserve_exact(&mut self, additional: usize) { |
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if additional > self.capacity().wrapping_sub(self.len) { |
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let Some(cap) = self.len().checked_add(additional) else { |
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alloc_overflow() |
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}; |
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self.allocate_inner(Self::new_layout(cap)); |
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} |
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} |
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|
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/// Allocates memory to the inner `RawJsString` by the given capacity.
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/// Capacity calculation is from [`std::vec::Vec::reserve`].
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fn allocate(&mut self, cap: usize) { |
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let cap = std::cmp::max(self.capacity() * 2, cap); |
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let cap = std::cmp::max(Self::MIN_NON_ZERO_CAP, cap); |
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self.allocate_inner(Self::new_layout(cap)); |
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} |
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|
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/// Appends an element to the inner `RawJsString` of `JsStringBuilder` without doing bounds check.
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/// # Safety
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///
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/// Caller should ensure the capacity is large enough to hold elements.
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#[inline] |
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pub unsafe fn push_unchecked(&mut self, v: D) { |
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// SAFETY: Caller should ensure the capacity is large enough to hold elements.
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unsafe { |
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self.data().add(self.len()).write(v); |
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self.len += 1; |
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} |
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} |
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|
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/// Returns true if this `JsStringBuilder` has a length of zero, and false otherwise.
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#[inline] |
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#[must_use] |
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pub fn is_empty(&self) -> bool { |
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self.len() == 0 |
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} |
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|
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/// Checks if all bytes in inner `RawJsString`'s data are ascii.
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#[inline] |
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#[must_use] |
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pub fn is_ascii(&self) -> bool { |
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// SAFETY:
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// `NonNull` verified for us that the pointer returned by `alloc` is valid,
|
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// meaning we can read to its pointed memory.
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let data = unsafe { |
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std::slice::from_raw_parts(self.data().cast::<u8>(), self.allocated_data_byte_len()) |
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}; |
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data.is_ascii() |
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} |
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|
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/// Extracts a slice containing the elements in the inner `RawJsString`.
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#[inline] |
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#[must_use] |
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pub fn as_slice(&self) -> &[D] { |
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if self.is_allocated() { |
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// SAFETY:
|
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// The inner `RawJsString` is allocated which means it is not null.
|
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unsafe { std::slice::from_raw_parts(self.data(), self.len()) } |
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} else { |
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&[] |
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} |
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} |
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|
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/// Extracts a mutable slice containing the elements in the inner `RawJsString`.
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///
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/// # Safety
|
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/// The caller must ensure that the content of the slice is valid encoding before the borrow ends.
|
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/// Use of a builder whose contents are not valid encoding is undefined behavior.
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#[inline] |
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#[must_use] |
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pub unsafe fn as_mut_slice(&mut self) -> &mut [D] { |
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if self.is_allocated() { |
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// SAFETY:
|
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// The inner `RawJsString` is allocated which means it is not null.
|
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unsafe { std::slice::from_raw_parts_mut(self.data(), self.len()) } |
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} else { |
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&mut [] |
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} |
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} |
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|
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/// Builds `JsString` from `JsStringBuilder`
|
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#[inline] |
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#[must_use] |
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fn build_inner(mut self, latin1: bool) -> JsString { |
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if self.is_empty() { |
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return JsString::default(); |
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} |
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let len = self.len(); |
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|
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// Shrink to fit the length.
|
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if len != self.capacity() { |
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let layout = Self::new_layout(self.len()); |
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self.allocate_inner(layout); |
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} |
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|
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let inner = self.inner; |
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|
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// SAFETY:
|
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// `NonNull` verified for us that the pointer returned by `alloc` is valid,
|
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// meaning we can write to its pointed memory.
|
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unsafe { |
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inner.as_ptr().write(RawJsString { |
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tagged_len: TaggedLen::new(len, latin1), |
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refcount: RefCount { |
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read_write: ManuallyDrop::new(Cell::new(1)), |
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}, |
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data: [0; 0], |
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}); |
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} |
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|
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// Tell the compiler not to call the destructor of `JsStringBuilder`,
|
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// becuase we move inner `RawJsString` to `JsString`.
|
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std::mem::forget(self); |
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JsString { |
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ptr: Tagged::from_non_null(inner), |
||||
} |
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} |
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} |
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|
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impl<D: Copy> Drop for JsStringBuilder<D> { |
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/// Set cold since [`JsStringBuilder`] should be created to build `JsString`
|
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#[cold] |
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#[inline] |
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fn drop(&mut self) { |
||||
if self.is_allocated() { |
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// SAFETY:
|
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// Allocation check has been made above.
|
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let layout = unsafe { self.current_layout() }; |
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// SAFETY:
|
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// layout: All the checks for the validity of the layout have already been made on `allocate_inner`.
|
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// `NonNull` verified for us that the pointer returned by `alloc` is valid,
|
||||
// meaning we can free its pointed memory.
|
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unsafe { |
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dealloc(self.inner.as_ptr().cast(), layout); |
||||
} |
||||
} |
||||
} |
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} |
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|
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impl<D: Copy> AddAssign<&JsStringBuilder<D>> for JsStringBuilder<D> { |
||||
#[inline] |
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fn add_assign(&mut self, rhs: &JsStringBuilder<D>) { |
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self.extend_from_slice(rhs.as_slice()); |
||||
} |
||||
} |
||||
|
||||
impl<D: Copy> AddAssign<&[D]> for JsStringBuilder<D> { |
||||
#[inline] |
||||
fn add_assign(&mut self, rhs: &[D]) { |
||||
self.extend_from_slice(rhs); |
||||
} |
||||
} |
||||
|
||||
impl<D: Copy> Add<&JsStringBuilder<D>> for JsStringBuilder<D> { |
||||
type Output = Self; |
||||
|
||||
#[inline] |
||||
#[must_use] |
||||
fn add(mut self, rhs: &JsStringBuilder<D>) -> Self::Output { |
||||
self.extend_from_slice(rhs.as_slice()); |
||||
self |
||||
} |
||||
} |
||||
|
||||
impl<D: Copy> Add<&[D]> for JsStringBuilder<D> { |
||||
type Output = Self; |
||||
|
||||
#[inline] |
||||
#[must_use] |
||||
fn add(mut self, rhs: &[D]) -> Self::Output { |
||||
self.extend_from_slice(rhs); |
||||
self |
||||
} |
||||
} |
||||
|
||||
impl<D: Copy> Extend<D> for JsStringBuilder<D> { |
||||
#[inline] |
||||
fn extend<I: IntoIterator<Item = D>>(&mut self, iter: I) { |
||||
let iterator = iter.into_iter(); |
||||
let (lower_bound, _) = iterator.size_hint(); |
||||
let require_cap = self.len() + lower_bound; |
||||
self.allocate_if_needed(require_cap); |
||||
iterator.for_each(|c| self.push(c)); |
||||
} |
||||
} |
||||
|
||||
impl<D: Copy> FromIterator<D> for JsStringBuilder<D> { |
||||
#[inline] |
||||
fn from_iter<T: IntoIterator<Item = D>>(iter: T) -> Self { |
||||
let mut builder = Self::new(); |
||||
builder.extend(iter); |
||||
builder |
||||
} |
||||
} |
||||
|
||||
impl<D: Copy> From<&[D]> for JsStringBuilder<D> { |
||||
#[inline] |
||||
#[must_use] |
||||
fn from(value: &[D]) -> Self { |
||||
let mut builder = Self::with_capacity(value.len()); |
||||
// SAFETY: The capacity is large enough to hold elements.
|
||||
unsafe { builder.extend_from_slice_unchecked(value) }; |
||||
builder |
||||
} |
||||
} |
||||
|
||||
impl<D: Copy + Eq + PartialEq> PartialEq for JsStringBuilder<D> { |
||||
#[inline] |
||||
#[must_use] |
||||
fn eq(&self, other: &Self) -> bool { |
||||
self.as_slice().eq(other.as_slice()) |
||||
} |
||||
} |
||||
|
||||
impl<D: Copy> Clone for JsStringBuilder<D> { |
||||
#[inline] |
||||
#[must_use] |
||||
fn clone(&self) -> Self { |
||||
if self.is_allocated() { |
||||
let mut builder = Self::with_capacity(self.capacity()); |
||||
// SAFETY: The capacity is large enough to hold elements.
|
||||
unsafe { builder.extend_from_slice_unchecked(self.as_slice()) }; |
||||
builder |
||||
} else { |
||||
Self::new() |
||||
} |
||||
} |
||||
|
||||
/// Performs copy-assignment from `source`.
|
||||
///
|
||||
/// Rewritten to avoid unnecessary allocation.
|
||||
#[inline] |
||||
fn clone_from(&mut self, source: &Self) { |
||||
let source_len = source.len(); |
||||
|
||||
if source_len > self.capacity() { |
||||
self.allocate(source_len); |
||||
} else { |
||||
// At this point, inner `RawJsString` of self or source can be not allocated,
|
||||
// returns earlier to avoid copying from/to `null`.
|
||||
if source_len == 0 { |
||||
// SAFETY: 0 is always less or equal to self's capacity.
|
||||
unsafe { self.set_len(0) }; |
||||
return; |
||||
} |
||||
} |
||||
|
||||
// SAFETY: self shoud be allocated after allocation.
|
||||
let self_data = unsafe { self.data() }; |
||||
|
||||
// SAFETY: source_len is greter than 0 so source shoud be allocated.
|
||||
let source_data = unsafe { source.data() }; |
||||
|
||||
// SAFETY: Borrow checker should not allow this to be overlapped and pointers are valid.
|
||||
unsafe { ptr::copy_nonoverlapping(source_data, self_data, source_len) }; |
||||
|
||||
// SAFETY: source_len has checked to be less or equal to self's capacity.
|
||||
unsafe { self.set_len(source_len) }; |
||||
} |
||||
} |
||||
|
||||
/// **`Latin1`** encoded `JsStringBuilder`
|
||||
/// # Warning
|
||||
/// If you are not sure the characters that will be added and don't want to preprocess them,
|
||||
/// use [`CommonJsStringBuilder`] instead.
|
||||
/// ## Examples
|
||||
///
|
||||
/// ```rust
|
||||
/// use boa_string::Latin1JsStringBuilder;
|
||||
/// let mut s = Latin1JsStringBuilder::new();
|
||||
/// s.push(b'x');
|
||||
/// s.extend_from_slice(&[b'1', b'2', b'3']);
|
||||
/// s.extend([b'1', b'2', b'3']);
|
||||
/// let js_string = s.build();
|
||||
/// ```
|
||||
pub type Latin1JsStringBuilder = JsStringBuilder<u8>; |
||||
|
||||
impl Latin1JsStringBuilder { |
||||
/// Builds a `JsString` if the current instance is strictly `ASCII`.
|
||||
///
|
||||
/// When the string contains characters outside the `ASCII` range, it cannot be determined
|
||||
/// whether the encoding is `Latin1` or others. Therefore, this method only returns a
|
||||
/// valid `JsString` when the instance is entirely `ASCII`. If any non-`ASCII` characters
|
||||
/// are present, it returns `None` to avoid ambiguity in encoding.
|
||||
///
|
||||
/// If the caller is certain that the string is encoded in `Latin1`,
|
||||
/// [`build_as_latin1`](Self::build_as_latin1) can be used to avoid the `ASCII` check.
|
||||
#[inline] |
||||
#[must_use] |
||||
pub fn build(self) -> Option<JsString> { |
||||
if self.is_ascii() { |
||||
Some(self.build_inner(true)) |
||||
} else { |
||||
None |
||||
} |
||||
} |
||||
|
||||
/// Builds `JsString` from `Latin1JsStringBuilder`, assume that the inner data is `Latin1` encoded
|
||||
///
|
||||
/// # Safety
|
||||
/// Caller must ensure that the string is encoded in `Latin1`.
|
||||
///
|
||||
/// If the string contains characters outside the `Latin1` range, it may lead to encoding errors,
|
||||
/// resulting in an incorrect or malformed `JsString`. This could cause undefined behavior
|
||||
/// when the resulting string is used in further operations or when interfacing with other
|
||||
/// parts of the system that expect valid `Latin1` encoded string.
|
||||
#[inline] |
||||
#[must_use] |
||||
pub unsafe fn build_as_latin1(self) -> JsString { |
||||
self.build_inner(true) |
||||
} |
||||
} |
||||
|
||||
/// **`UTF-16`** encoded `JsStringBuilder`
|
||||
/// ## Examples
|
||||
///
|
||||
/// ```rust
|
||||
/// use boa_string::Utf16JsStringBuilder;
|
||||
/// let mut s = Utf16JsStringBuilder::new();
|
||||
/// s.push(b'x' as u16);
|
||||
/// s.extend_from_slice(&[b'1', b'2', b'3'].map(u16::from));
|
||||
/// s.extend([0xD83C, 0xDFB9, 0xD83C, 0xDFB6, 0xD83C, 0xDFB5,]); // 🎹🎶🎵
|
||||
/// let js_string = s.build();
|
||||
/// ```
|
||||
pub type Utf16JsStringBuilder = JsStringBuilder<u16>; |
||||
|
||||
impl Utf16JsStringBuilder { |
||||
/// Builds `JsString` from `Utf16JsStringBuilder`
|
||||
#[inline] |
||||
#[must_use] |
||||
pub fn build(self) -> JsString { |
||||
self.build_inner(false) |
||||
} |
||||
} |
||||
|
||||
/// Represents a segment of a string used to construct a [`JsString`].
|
||||
#[derive(Clone, Debug)] |
||||
pub enum Segment<'a> { |
||||
/// A string segment represented as a `JsString`.
|
||||
String(JsString), |
||||
|
||||
/// A string segment represented as a `JsStr`.
|
||||
Str(JsStr<'a>), |
||||
|
||||
/// A string segment represented as a byte.
|
||||
Latin1(u8), |
||||
|
||||
/// A Unicode code point segment represented as a character.
|
||||
CodePoint(char), |
||||
} |
||||
|
||||
impl Segment<'_> { |
||||
/// Checks if the segment consists solely of `ASCII` characters.
|
||||
#[inline] |
||||
#[must_use] |
||||
fn is_ascii(&self) -> bool { |
||||
match self { |
||||
Segment::String(s) => s.as_str().is_latin1(), |
||||
Segment::Str(s) => s.is_latin1(), |
||||
Segment::Latin1(b) => *b <= 0x7f, |
||||
Segment::CodePoint(ch) => *ch as u32 <= 0x7F, |
||||
} |
||||
} |
||||
} |
||||
|
||||
impl From<JsString> for Segment<'_> { |
||||
#[inline] |
||||
fn from(value: JsString) -> Self { |
||||
Self::String(value) |
||||
} |
||||
} |
||||
|
||||
impl From<String> for Segment<'_> { |
||||
#[inline] |
||||
fn from(value: String) -> Self { |
||||
Self::String(value.into()) |
||||
} |
||||
} |
||||
|
||||
impl From<&[u16]> for Segment<'_> { |
||||
#[inline] |
||||
fn from(value: &[u16]) -> Self { |
||||
Self::String(value.into()) |
||||
} |
||||
} |
||||
|
||||
impl From<&str> for Segment<'_> { |
||||
#[inline] |
||||
fn from(value: &str) -> Self { |
||||
Self::String(value.into()) |
||||
} |
||||
} |
||||
|
||||
impl<'seg, 'ref_str: 'seg> From<JsStr<'ref_str>> for Segment<'seg> { |
||||
#[inline] |
||||
fn from(value: JsStr<'ref_str>) -> Self { |
||||
Self::Str(value) |
||||
} |
||||
} |
||||
|
||||
impl From<u8> for Segment<'_> { |
||||
#[inline] |
||||
fn from(value: u8) -> Self { |
||||
Self::Latin1(value) |
||||
} |
||||
} |
||||
|
||||
impl From<char> for Segment<'_> { |
||||
#[inline] |
||||
fn from(value: char) -> Self { |
||||
Self::CodePoint(value) |
||||
} |
||||
} |
||||
|
||||
/// Common `JsString` builder that accepts multiple variant of string or character.
|
||||
///
|
||||
/// Originally based on [kiesel-js](https://codeberg.org/kiesel-js/kiesel/src/branch/main/src/types/language/String/Builder.zig)
|
||||
#[derive(Clone, Debug, Default)] |
||||
pub struct CommonJsStringBuilder<'a> { |
||||
segments: Vec<Segment<'a>>, |
||||
} |
||||
|
||||
impl<'seg, 'ref_str: 'seg> CommonJsStringBuilder<'seg> { |
||||
/// Creates a new `CommonJsStringBuilder` with capacity of zero.
|
||||
#[inline] |
||||
#[must_use] |
||||
pub const fn new() -> Self { |
||||
Self { |
||||
segments: Vec::new(), |
||||
} |
||||
} |
||||
|
||||
/// Similar to `Vec::with_capacity`.
|
||||
///
|
||||
/// Creates a new `CommonJsStringBuilder` with given capacity.
|
||||
#[inline] |
||||
#[must_use] |
||||
pub fn with_capacity(capacity: usize) -> Self { |
||||
Self { |
||||
segments: Vec::with_capacity(capacity), |
||||
} |
||||
} |
||||
|
||||
/// Similar to `Vec::reserve`.
|
||||
///
|
||||
/// Reserves additional capacity for the inner vector.
|
||||
#[inline] |
||||
pub fn reserve(&mut self, additional: usize) { |
||||
self.segments.reserve(additional); |
||||
} |
||||
|
||||
/// Similar to `Vec::reserve_exact`.
|
||||
///
|
||||
/// Reserves the minimum capacity for the inner vector.
|
||||
#[inline] |
||||
pub fn reserve_exact(&mut self, additional: usize) { |
||||
self.segments.reserve_exact(additional); |
||||
} |
||||
|
||||
/// Appends string segments to the back of the inner vector.
|
||||
#[inline] |
||||
pub fn push<T: Into<Segment<'ref_str>>>(&mut self, seg: T) { |
||||
self.segments.push(seg.into()); |
||||
} |
||||
|
||||
/// Checks if all string segments contains only `ASCII` bytes.
|
||||
#[inline] |
||||
#[must_use] |
||||
pub fn is_ascii(&self) -> bool { |
||||
self.segments.iter().all(Segment::is_ascii) |
||||
} |
||||
|
||||
/// Returns the number of string segment in inner vector.
|
||||
#[inline] |
||||
#[must_use] |
||||
pub fn len(&self) -> usize { |
||||
self.segments.len() |
||||
} |
||||
|
||||
/// Returns true if this `CommonJsStringBuilder` has a length of zero, and false otherwise.
|
||||
#[inline] |
||||
#[must_use] |
||||
pub fn is_empty(&self) -> bool { |
||||
self.len() == 0 |
||||
} |
||||
|
||||
/// Builds `Latin1` encoded `JsString` from string segments.
|
||||
///
|
||||
/// This doesn't consume the builder itself because it may fails to build
|
||||
/// and the caller may wants to keep the builder for further operations.
|
||||
///
|
||||
/// This processes the following types of segments:
|
||||
///
|
||||
/// - `Segment::String(s)`: Encodes the string if it can be represented in `Latin1`.
|
||||
/// - `Segment::Str(s)`: Encodes the string slice if it can be represented in `Latin1`.
|
||||
/// - `Segment::Latin1(b)`: Encodes the byte if it's within the `ASCII` range.
|
||||
/// - `Segment::CodePoint(ch)`: Encodes the code point by converting it to a byte if it's within the `ASCII` range.
|
||||
///
|
||||
/// Return `None` if any segment fails to encode.
|
||||
#[inline] |
||||
#[must_use] |
||||
#[allow(clippy::cast_lossless)] |
||||
pub fn build_from_latin1(&self) -> Option<JsString> { |
||||
let mut builder = Latin1JsStringBuilder::new(); |
||||
for seg in &self.segments { |
||||
match seg { |
||||
Segment::String(s) => { |
||||
if let Some(data) = s.as_str().as_latin1() { |
||||
builder.extend_from_slice(data); |
||||
} else { |
||||
return None; |
||||
} |
||||
} |
||||
Segment::Str(s) => { |
||||
if let Some(data) = s.as_latin1() { |
||||
builder.extend_from_slice(data); |
||||
} else { |
||||
return None; |
||||
} |
||||
} |
||||
Segment::Latin1(b) => { |
||||
if *b <= 0x7f { |
||||
builder.push(*b); |
||||
} else { |
||||
return None; |
||||
} |
||||
} |
||||
Segment::CodePoint(ch) => { |
||||
if let Ok(b) = u8::try_from(*ch as u32) { |
||||
builder.push(b); |
||||
} else { |
||||
return None; |
||||
} |
||||
} |
||||
} |
||||
} |
||||
builder.build() |
||||
} |
||||
|
||||
/// Builds `Utf-16` encoded `JsString` from string segments.
|
||||
#[inline] |
||||
#[must_use] |
||||
#[allow(clippy::cast_possible_truncation)] |
||||
pub fn build_from_utf16(self) -> JsString { |
||||
let mut builder = Utf16JsStringBuilder::new(); |
||||
for seg in self.segments { |
||||
match seg { |
||||
Segment::String(s) => { |
||||
let js_str = s.as_str(); |
||||
match js_str.variant() { |
||||
JsStrVariant::Latin1(s) => builder.extend(s.iter().copied().map(u16::from)), |
||||
JsStrVariant::Utf16(s) => builder.extend_from_slice(s), |
||||
} |
||||
} |
||||
Segment::Str(s) => match s.variant() { |
||||
JsStrVariant::Latin1(s) => builder.extend(s.iter().copied().map(u16::from)), |
||||
JsStrVariant::Utf16(s) => builder.extend_from_slice(s), |
||||
}, |
||||
Segment::Latin1(latin1) => builder.push(u16::from(latin1)), |
||||
Segment::CodePoint(code_point) => { |
||||
builder.extend_from_slice(code_point.encode_utf16(&mut [0_u16; 2])); |
||||
} |
||||
} |
||||
} |
||||
builder.build() |
||||
} |
||||
|
||||
/// Builds `JsString` from `CommonJsStringBuilder`,
|
||||
///
|
||||
/// This function first checks if the instance is empty:
|
||||
/// - If it is empty, it returns the default `JsString`.
|
||||
/// - If it contains only ASCII characters, it safely encodes it as `Latin1`.
|
||||
/// - If it contains non-ASCII characters, it falls back to encoding using `UTF-16`.
|
||||
#[inline] |
||||
#[must_use] |
||||
pub fn build(self) -> JsString { |
||||
if self.is_empty() { |
||||
JsString::default() |
||||
} else if self.is_ascii() { |
||||
// SAFETY:
|
||||
// All string segment contains only ascii byte, so this can be encoded as `Latin1`.
|
||||
unsafe { self.build_as_latin1() } |
||||
} else { |
||||
self.build_from_utf16() |
||||
} |
||||
} |
||||
|
||||
/// Builds `Latin1` encoded `JsString` from `CommonJsStringBuilder`, return `None` if segments can't be encoded as `Latin1`
|
||||
///
|
||||
/// # Safety
|
||||
/// Caller must ensure that the string segments can be `Latin1` encoded.
|
||||
///
|
||||
/// If string segments can't be `Latin1` encoded, it may lead to encoding errors,
|
||||
/// resulting in an incorrect or malformed `JsString`. This could cause undefined behavior
|
||||
/// when the resulting string is used in further operations or when interfacing with other
|
||||
/// parts of the system that expect valid `Latin1` encoded string.
|
||||
#[inline] |
||||
#[must_use] |
||||
pub unsafe fn build_as_latin1(self) -> JsString { |
||||
let mut builder = Latin1JsStringBuilder::new(); |
||||
for seg in self.segments { |
||||
match seg { |
||||
Segment::String(s) => { |
||||
let js_str = s.as_str(); |
||||
let Some(s) = js_str.as_latin1() else { |
||||
unreachable!("string segment shoud be latin1") |
||||
}; |
||||
builder.extend_from_slice(s); |
||||
} |
||||
Segment::Str(s) => { |
||||
let Some(s) = s.as_latin1() else { |
||||
unreachable!("string segment shoud be latin1") |
||||
}; |
||||
builder.extend_from_slice(s); |
||||
} |
||||
Segment::Latin1(latin1) => builder.push(latin1), |
||||
Segment::CodePoint(code_point) => builder.push(code_point as u8), |
||||
} |
||||
} |
||||
// SAFETY: All string segments can be encoded as `Latin1` string.
|
||||
unsafe { builder.build_as_latin1() } |
||||
} |
||||
} |
||||
|
||||
impl<'ref_str, T: Into<Segment<'ref_str>>> AddAssign<T> for CommonJsStringBuilder<'ref_str> { |
||||
#[inline] |
||||
fn add_assign(&mut self, rhs: T) { |
||||
self.push(rhs); |
||||
} |
||||
} |
||||
|
||||
impl<'ref_str, T: Into<Segment<'ref_str>>> Add<T> for CommonJsStringBuilder<'ref_str> { |
||||
type Output = Self; |
||||
|
||||
#[inline] |
||||
#[must_use] |
||||
fn add(mut self, rhs: T) -> Self::Output { |
||||
self.push(rhs); |
||||
self |
||||
} |
||||
} |
||||
Loading…
Reference in new issue