1 // A generic trait to abstract the rewriting of an element (of the AST). 2 3 use std::cell::{Cell, RefCell}; 4 use std::rc::Rc; 5 6 use rustc_ast::ptr; 7 use rustc_span::Span; 8 9 use crate::config::{Config, IndentStyle}; 10 use crate::parse::session::ParseSess; 11 use crate::shape::Shape; 12 use crate::skip::SkipContext; 13 use crate::visitor::SnippetProvider; 14 use crate::FormatReport; 15 16 pub(crate) trait Rewrite { 17 /// Rewrite self into shape. rewrite(&self, context: &RewriteContext<'_>, shape: Shape) -> Option<String>18 fn rewrite(&self, context: &RewriteContext<'_>, shape: Shape) -> Option<String>; 19 } 20 21 impl<T: Rewrite> Rewrite for ptr::P<T> { rewrite(&self, context: &RewriteContext<'_>, shape: Shape) -> Option<String>22 fn rewrite(&self, context: &RewriteContext<'_>, shape: Shape) -> Option<String> { 23 (**self).rewrite(context, shape) 24 } 25 } 26 27 #[derive(Clone)] 28 pub(crate) struct RewriteContext<'a> { 29 pub(crate) parse_sess: &'a ParseSess, 30 pub(crate) config: &'a Config, 31 pub(crate) inside_macro: Rc<Cell<bool>>, 32 // Force block indent style even if we are using visual indent style. 33 pub(crate) use_block: Cell<bool>, 34 // When `is_if_else_block` is true, unindent the comment on top 35 // of the `else` or `else if`. 36 pub(crate) is_if_else_block: Cell<bool>, 37 // When rewriting chain, veto going multi line except the last element 38 pub(crate) force_one_line_chain: Cell<bool>, 39 pub(crate) snippet_provider: &'a SnippetProvider, 40 // Used for `format_snippet` 41 pub(crate) macro_rewrite_failure: Cell<bool>, 42 pub(crate) is_macro_def: bool, 43 pub(crate) report: FormatReport, 44 pub(crate) skip_context: SkipContext, 45 pub(crate) skipped_range: Rc<RefCell<Vec<(usize, usize)>>>, 46 } 47 48 pub(crate) struct InsideMacroGuard { 49 is_nested_macro_context: bool, 50 inside_macro_ref: Rc<Cell<bool>>, 51 } 52 53 impl InsideMacroGuard { is_nested(&self) -> bool54 pub(crate) fn is_nested(&self) -> bool { 55 self.is_nested_macro_context 56 } 57 } 58 59 impl Drop for InsideMacroGuard { drop(&mut self)60 fn drop(&mut self) { 61 self.inside_macro_ref.replace(self.is_nested_macro_context); 62 } 63 } 64 65 impl<'a> RewriteContext<'a> { snippet(&self, span: Span) -> &str66 pub(crate) fn snippet(&self, span: Span) -> &str { 67 self.snippet_provider.span_to_snippet(span).unwrap() 68 } 69 70 /// Returns `true` if we should use block indent style for rewriting function call. use_block_indent(&self) -> bool71 pub(crate) fn use_block_indent(&self) -> bool { 72 self.config.indent_style() == IndentStyle::Block || self.use_block.get() 73 } 74 budget(&self, used_width: usize) -> usize75 pub(crate) fn budget(&self, used_width: usize) -> usize { 76 self.config.max_width().saturating_sub(used_width) 77 } 78 inside_macro(&self) -> bool79 pub(crate) fn inside_macro(&self) -> bool { 80 self.inside_macro.get() 81 } 82 enter_macro(&self) -> InsideMacroGuard83 pub(crate) fn enter_macro(&self) -> InsideMacroGuard { 84 let is_nested_macro_context = self.inside_macro.replace(true); 85 InsideMacroGuard { 86 is_nested_macro_context, 87 inside_macro_ref: self.inside_macro.clone(), 88 } 89 } 90 leave_macro(&self)91 pub(crate) fn leave_macro(&self) { 92 self.inside_macro.replace(false); 93 } 94 is_if_else_block(&self) -> bool95 pub(crate) fn is_if_else_block(&self) -> bool { 96 self.is_if_else_block.get() 97 } 98 } 99