rust/src/visitor.rs

1020 lines
40 KiB
Rust

use std::cell::{Cell, RefCell};
use std::rc::Rc;
use rustc_ast::{ast, token::Delimiter, visit};
use rustc_data_structures::sync::Lrc;
use rustc_span::{symbol, BytePos, Pos, Span};
use crate::attr::*;
use crate::comment::{contains_comment, rewrite_comment, CodeCharKind, CommentCodeSlices};
use crate::config::Version;
use crate::config::{BraceStyle, Config, MacroSelector};
use crate::coverage::transform_missing_snippet;
use crate::items::{
format_impl, format_trait, format_trait_alias, is_mod_decl, is_use_item, rewrite_extern_crate,
rewrite_type_alias, FnBraceStyle, FnSig, ItemVisitorKind, StaticParts, StructParts,
};
use crate::macros::{macro_style, rewrite_macro, rewrite_macro_def, MacroPosition};
use crate::modules::Module;
use crate::parse::session::ParseSess;
use crate::rewrite::{Rewrite, RewriteContext};
use crate::shape::{Indent, Shape};
use crate::skip::{is_skip_attr, SkipContext};
use crate::source_map::{LineRangeUtils, SpanUtils};
use crate::spanned::Spanned;
use crate::stmt::Stmt;
use crate::utils::{
self, contains_skip, count_newlines, depr_skip_annotation, format_unsafety, inner_attributes,
last_line_width, mk_sp, ptr_vec_to_ref_vec, rewrite_ident, starts_with_newline, stmt_expr,
};
use crate::{ErrorKind, FormatReport, FormattingError};
/// Creates a string slice corresponding to the specified span.
pub(crate) struct SnippetProvider {
/// A pointer to the content of the file we are formatting.
big_snippet: Lrc<String>,
/// A position of the start of `big_snippet`, used as an offset.
start_pos: usize,
/// An end position of the file that this snippet lives.
end_pos: usize,
}
impl SnippetProvider {
pub(crate) fn span_to_snippet(&self, span: Span) -> Option<&str> {
let start_index = span.lo().to_usize().checked_sub(self.start_pos)?;
let end_index = span.hi().to_usize().checked_sub(self.start_pos)?;
Some(&self.big_snippet[start_index..end_index])
}
pub(crate) fn new(start_pos: BytePos, end_pos: BytePos, big_snippet: Lrc<String>) -> Self {
let start_pos = start_pos.to_usize();
let end_pos = end_pos.to_usize();
SnippetProvider {
big_snippet,
start_pos,
end_pos,
}
}
pub(crate) fn entire_snippet(&self) -> &str {
self.big_snippet.as_str()
}
pub(crate) fn start_pos(&self) -> BytePos {
BytePos::from_usize(self.start_pos)
}
pub(crate) fn end_pos(&self) -> BytePos {
BytePos::from_usize(self.end_pos)
}
}
pub(crate) struct FmtVisitor<'a> {
parent_context: Option<&'a RewriteContext<'a>>,
pub(crate) parse_sess: &'a ParseSess,
pub(crate) buffer: String,
pub(crate) last_pos: BytePos,
// FIXME: use an RAII util or closure for indenting
pub(crate) block_indent: Indent,
pub(crate) config: &'a Config,
pub(crate) is_if_else_block: bool,
pub(crate) snippet_provider: &'a SnippetProvider,
pub(crate) line_number: usize,
/// List of 1-based line ranges which were annotated with skip
/// Both bounds are inclusifs.
pub(crate) skipped_range: Rc<RefCell<Vec<(usize, usize)>>>,
pub(crate) macro_rewrite_failure: bool,
pub(crate) report: FormatReport,
pub(crate) skip_context: SkipContext,
pub(crate) is_macro_def: bool,
}
impl<'a> Drop for FmtVisitor<'a> {
fn drop(&mut self) {
if let Some(ctx) = self.parent_context {
if self.macro_rewrite_failure {
ctx.macro_rewrite_failure.replace(true);
}
}
}
}
impl<'b, 'a: 'b> FmtVisitor<'a> {
fn set_parent_context(&mut self, context: &'a RewriteContext<'_>) {
self.parent_context = Some(context);
}
pub(crate) fn shape(&self) -> Shape {
Shape::indented(self.block_indent, self.config)
}
fn next_span(&self, hi: BytePos) -> Span {
mk_sp(self.last_pos, hi)
}
fn visit_stmt(&mut self, stmt: &Stmt<'_>, include_empty_semi: bool) {
debug!(
"visit_stmt: {}",
self.parse_sess.span_to_debug_info(stmt.span())
);
if stmt.is_empty() {
// If the statement is empty, just skip over it. Before that, make sure any comment
// snippet preceding the semicolon is picked up.
let snippet = self.snippet(mk_sp(self.last_pos, stmt.span().lo()));
let original_starts_with_newline = snippet
.find(|c| c != ' ')
.map_or(false, |i| starts_with_newline(&snippet[i..]));
let snippet = snippet.trim();
if !snippet.is_empty() {
// FIXME(calebcartwright 2021-01-03) - This exists strictly to maintain legacy
// formatting where rustfmt would preserve redundant semicolons on Items in a
// statement position.
// See comment within `walk_stmts` for more info
if include_empty_semi {
self.format_missing(stmt.span().hi());
} else {
if original_starts_with_newline {
self.push_str("\n");
}
self.push_str(&self.block_indent.to_string(self.config));
self.push_str(snippet);
}
} else if include_empty_semi {
self.push_str(";");
}
self.last_pos = stmt.span().hi();
return;
}
match stmt.as_ast_node().kind {
ast::StmtKind::Item(ref item) => {
self.visit_item(item);
self.last_pos = stmt.span().hi();
}
ast::StmtKind::Local(..) | ast::StmtKind::Expr(..) | ast::StmtKind::Semi(..) => {
let attrs = get_attrs_from_stmt(stmt.as_ast_node());
if contains_skip(attrs) {
self.push_skipped_with_span(
attrs,
stmt.span(),
get_span_without_attrs(stmt.as_ast_node()),
);
} else {
let shape = self.shape();
let rewrite = self.with_context(|ctx| stmt.rewrite(ctx, shape));
self.push_rewrite(stmt.span(), rewrite)
}
}
ast::StmtKind::MacCall(ref mac_stmt) => {
if self.visit_attrs(&mac_stmt.attrs, ast::AttrStyle::Outer) {
self.push_skipped_with_span(
&mac_stmt.attrs,
stmt.span(),
get_span_without_attrs(stmt.as_ast_node()),
);
} else {
self.visit_mac(&mac_stmt.mac, None, MacroPosition::Statement);
}
self.format_missing(stmt.span().hi());
}
ast::StmtKind::Empty => (),
}
}
/// Remove spaces between the opening brace and the first statement or the inner attribute
/// of the block.
fn trim_spaces_after_opening_brace(
&mut self,
b: &ast::Block,
inner_attrs: Option<&[ast::Attribute]>,
) {
if let Some(first_stmt) = b.stmts.first() {
let hi = inner_attrs
.and_then(|attrs| inner_attributes(attrs).first().map(|attr| attr.span.lo()))
.unwrap_or_else(|| first_stmt.span().lo());
let missing_span = self.next_span(hi);
let snippet = self.snippet(missing_span);
let len = CommentCodeSlices::new(snippet)
.next()
.and_then(|(kind, _, s)| {
if kind == CodeCharKind::Normal {
s.rfind('\n')
} else {
None
}
});
if let Some(len) = len {
self.last_pos = self.last_pos + BytePos::from_usize(len);
}
}
}
pub(crate) fn visit_block(
&mut self,
b: &ast::Block,
inner_attrs: Option<&[ast::Attribute]>,
has_braces: bool,
) {
debug!(
"visit_block: {}",
self.parse_sess.span_to_debug_info(b.span),
);
// Check if this block has braces.
let brace_compensation = BytePos(if has_braces { 1 } else { 0 });
self.last_pos = self.last_pos + brace_compensation;
self.block_indent = self.block_indent.block_indent(self.config);
self.push_str("{");
self.trim_spaces_after_opening_brace(b, inner_attrs);
// Format inner attributes if available.
if let Some(attrs) = inner_attrs {
self.visit_attrs(attrs, ast::AttrStyle::Inner);
}
self.walk_block_stmts(b);
if !b.stmts.is_empty() {
if let Some(expr) = stmt_expr(&b.stmts[b.stmts.len() - 1]) {
if utils::semicolon_for_expr(&self.get_context(), expr) {
self.push_str(";");
}
}
}
let rest_span = self.next_span(b.span.hi());
if out_of_file_lines_range!(self, rest_span) {
self.push_str(self.snippet(rest_span));
self.block_indent = self.block_indent.block_unindent(self.config);
} else {
// Ignore the closing brace.
let missing_span = self.next_span(b.span.hi() - brace_compensation);
self.close_block(missing_span, self.unindent_comment_on_closing_brace(b));
}
self.last_pos = source!(self, b.span).hi();
}
fn close_block(&mut self, span: Span, unindent_comment: bool) {
let config = self.config;
let mut last_hi = span.lo();
let mut unindented = false;
let mut prev_ends_with_newline = false;
let mut extra_newline = false;
let skip_normal = |s: &str| {
let trimmed = s.trim();
trimmed.is_empty() || trimmed.chars().all(|c| c == ';')
};
let comment_snippet = self.snippet(span);
let align_to_right = if unindent_comment && contains_comment(comment_snippet) {
let first_lines = comment_snippet.splitn(2, '/').next().unwrap_or("");
last_line_width(first_lines) > last_line_width(comment_snippet)
} else {
false
};
for (kind, offset, sub_slice) in CommentCodeSlices::new(comment_snippet) {
let sub_slice = transform_missing_snippet(config, sub_slice);
debug!("close_block: {:?} {:?} {:?}", kind, offset, sub_slice);
match kind {
CodeCharKind::Comment => {
if !unindented && unindent_comment && !align_to_right {
unindented = true;
self.block_indent = self.block_indent.block_unindent(config);
}
let span_in_between = mk_sp(last_hi, span.lo() + BytePos::from_usize(offset));
let snippet_in_between = self.snippet(span_in_between);
let mut comment_on_same_line = !snippet_in_between.contains('\n');
let mut comment_shape =
Shape::indented(self.block_indent, config).comment(config);
if self.config.version() == Version::Two && comment_on_same_line {
self.push_str(" ");
// put the first line of the comment on the same line as the
// block's last line
match sub_slice.find('\n') {
None => {
self.push_str(&sub_slice);
}
Some(offset) if offset + 1 == sub_slice.len() => {
self.push_str(&sub_slice[..offset]);
}
Some(offset) => {
let first_line = &sub_slice[..offset];
self.push_str(first_line);
self.push_str(&self.block_indent.to_string_with_newline(config));
// put the other lines below it, shaping it as needed
let other_lines = &sub_slice[offset + 1..];
let comment_str =
rewrite_comment(other_lines, false, comment_shape, config);
match comment_str {
Some(ref s) => self.push_str(s),
None => self.push_str(other_lines),
}
}
}
} else {
if comment_on_same_line {
// 1 = a space before `//`
let offset_len = 1 + last_line_width(&self.buffer)
.saturating_sub(self.block_indent.width());
match comment_shape
.visual_indent(offset_len)
.sub_width(offset_len)
{
Some(shp) => comment_shape = shp,
None => comment_on_same_line = false,
}
};
if comment_on_same_line {
self.push_str(" ");
} else {
if count_newlines(snippet_in_between) >= 2 || extra_newline {
self.push_str("\n");
}
self.push_str(&self.block_indent.to_string_with_newline(config));
}
let comment_str = rewrite_comment(&sub_slice, false, comment_shape, config);
match comment_str {
Some(ref s) => self.push_str(s),
None => self.push_str(&sub_slice),
}
}
}
CodeCharKind::Normal if skip_normal(&sub_slice) => {
extra_newline = prev_ends_with_newline && sub_slice.contains('\n');
continue;
}
CodeCharKind::Normal => {
self.push_str(&self.block_indent.to_string_with_newline(config));
self.push_str(sub_slice.trim());
}
}
prev_ends_with_newline = sub_slice.ends_with('\n');
extra_newline = false;
last_hi = span.lo() + BytePos::from_usize(offset + sub_slice.len());
}
if unindented {
self.block_indent = self.block_indent.block_indent(self.config);
}
self.block_indent = self.block_indent.block_unindent(self.config);
self.push_str(&self.block_indent.to_string_with_newline(config));
self.push_str("}");
}
fn unindent_comment_on_closing_brace(&self, b: &ast::Block) -> bool {
self.is_if_else_block && !b.stmts.is_empty()
}
// Note that this only gets called for function definitions. Required methods
// on traits do not get handled here.
pub(crate) fn visit_fn(
&mut self,
fk: visit::FnKind<'_>,
fd: &ast::FnDecl,
s: Span,
defaultness: ast::Defaultness,
inner_attrs: Option<&[ast::Attribute]>,
) {
let indent = self.block_indent;
let block;
let rewrite = match fk {
visit::FnKind::Fn(_, ident, _, _, _, Some(ref b)) => {
block = b;
self.rewrite_fn_before_block(
indent,
ident,
&FnSig::from_fn_kind(&fk, fd, defaultness),
mk_sp(s.lo(), b.span.lo()),
)
}
_ => unreachable!(),
};
if let Some((fn_str, fn_brace_style)) = rewrite {
self.format_missing_with_indent(source!(self, s).lo());
if let Some(rw) = self.single_line_fn(&fn_str, block, inner_attrs) {
self.push_str(&rw);
self.last_pos = s.hi();
return;
}
self.push_str(&fn_str);
match fn_brace_style {
FnBraceStyle::SameLine => self.push_str(" "),
FnBraceStyle::NextLine => {
self.push_str(&self.block_indent.to_string_with_newline(self.config))
}
_ => unreachable!(),
}
self.last_pos = source!(self, block.span).lo();
} else {
self.format_missing(source!(self, block.span).lo());
}
self.visit_block(block, inner_attrs, true)
}
pub(crate) fn visit_item(&mut self, item: &ast::Item) {
skip_out_of_file_lines_range_visitor!(self, item.span);
// This is where we bail out if there is a skip attribute. This is only
// complex in the module case. It is complex because the module could be
// in a separate file and there might be attributes in both files, but
// the AST lumps them all together.
let filtered_attrs;
let mut attrs = &item.attrs;
let skip_context_saved = self.skip_context.clone();
self.skip_context.update_with_attrs(attrs);
let should_visit_node_again = match item.kind {
// For use/extern crate items, skip rewriting attributes but check for a skip attribute.
ast::ItemKind::Use(..) | ast::ItemKind::ExternCrate(_) => {
if contains_skip(attrs) {
self.push_skipped_with_span(attrs.as_slice(), item.span(), item.span());
false
} else {
true
}
}
// Module is inline, in this case we treat it like any other item.
_ if !is_mod_decl(item) => {
if self.visit_attrs(&item.attrs, ast::AttrStyle::Outer) {
self.push_skipped_with_span(item.attrs.as_slice(), item.span(), item.span());
false
} else {
true
}
}
// Module is not inline, but should be skipped.
ast::ItemKind::Mod(..) if contains_skip(&item.attrs) => false,
// Module is not inline and should not be skipped. We want
// to process only the attributes in the current file.
ast::ItemKind::Mod(..) => {
filtered_attrs = filter_inline_attrs(&item.attrs, item.span());
// Assert because if we should skip it should be caught by
// the above case.
assert!(!self.visit_attrs(&filtered_attrs, ast::AttrStyle::Outer));
attrs = &filtered_attrs;
true
}
_ => {
if self.visit_attrs(&item.attrs, ast::AttrStyle::Outer) {
self.push_skipped_with_span(item.attrs.as_slice(), item.span(), item.span());
false
} else {
true
}
}
};
// TODO(calebcartwright): consider enabling box_patterns feature gate
if should_visit_node_again {
match item.kind {
ast::ItemKind::Use(ref tree) => self.format_import(item, tree),
ast::ItemKind::Impl(ref iimpl) => {
let block_indent = self.block_indent;
let rw = self.with_context(|ctx| format_impl(ctx, item, iimpl, block_indent));
self.push_rewrite(item.span, rw);
}
ast::ItemKind::Trait(..) => {
let block_indent = self.block_indent;
let rw = self.with_context(|ctx| format_trait(ctx, item, block_indent));
self.push_rewrite(item.span, rw);
}
ast::ItemKind::TraitAlias(ref generics, ref generic_bounds) => {
let shape = Shape::indented(self.block_indent, self.config);
let rw = format_trait_alias(
&self.get_context(),
item.ident,
&item.vis,
generics,
generic_bounds,
shape,
);
self.push_rewrite(item.span, rw);
}
ast::ItemKind::ExternCrate(_) => {
let rw = rewrite_extern_crate(&self.get_context(), item, self.shape());
let span = if attrs.is_empty() {
item.span
} else {
mk_sp(attrs[0].span.lo(), item.span.hi())
};
self.push_rewrite(span, rw);
}
ast::ItemKind::Struct(..) | ast::ItemKind::Union(..) => {
self.visit_struct(&StructParts::from_item(item));
}
ast::ItemKind::Enum(ref def, ref generics) => {
self.format_missing_with_indent(source!(self, item.span).lo());
self.visit_enum(item.ident, &item.vis, def, generics, item.span);
self.last_pos = source!(self, item.span).hi();
}
ast::ItemKind::Mod(unsafety, ref mod_kind) => {
self.format_missing_with_indent(source!(self, item.span).lo());
self.format_mod(mod_kind, unsafety, &item.vis, item.span, item.ident, attrs);
}
ast::ItemKind::MacCall(ref mac) => {
self.visit_mac(mac, Some(item.ident), MacroPosition::Item);
}
ast::ItemKind::ForeignMod(ref foreign_mod) => {
self.format_missing_with_indent(source!(self, item.span).lo());
self.format_foreign_mod(foreign_mod, item.span);
}
ast::ItemKind::Static(..) | ast::ItemKind::Const(..) => {
self.visit_static(&StaticParts::from_item(item));
}
ast::ItemKind::Fn(ref fn_kind) => {
let ast::Fn {
defaultness,
ref sig,
ref generics,
ref body,
} = **fn_kind;
if let Some(ref body) = body {
let inner_attrs = inner_attributes(&item.attrs);
let fn_ctxt = match sig.header.ext {
ast::Extern::None => visit::FnCtxt::Free,
_ => visit::FnCtxt::Foreign,
};
self.visit_fn(
visit::FnKind::Fn(
fn_ctxt,
item.ident,
sig,
&item.vis,
generics,
Some(body),
),
&sig.decl,
item.span,
defaultness,
Some(&inner_attrs),
)
} else {
let indent = self.block_indent;
let rewrite = self.rewrite_required_fn(
indent, item.ident, sig, &item.vis, generics, item.span,
);
self.push_rewrite(item.span, rewrite);
}
}
ast::ItemKind::TyAlias(ref ty_alias) => {
use ItemVisitorKind::Item;
self.visit_ty_alias_kind(ty_alias, &Item(item), item.span);
}
ast::ItemKind::GlobalAsm(..) => {
let snippet = Some(self.snippet(item.span).to_owned());
self.push_rewrite(item.span, snippet);
}
ast::ItemKind::MacroDef(ref def) => {
let rewrite = rewrite_macro_def(
&self.get_context(),
self.shape(),
self.block_indent,
def,
item.ident,
&item.vis,
item.span,
);
self.push_rewrite(item.span, rewrite);
}
};
}
self.skip_context = skip_context_saved;
}
fn visit_ty_alias_kind(
&mut self,
ty_kind: &ast::TyAlias,
visitor_kind: &ItemVisitorKind<'_>,
span: Span,
) {
let rewrite = rewrite_type_alias(
ty_kind,
&self.get_context(),
self.block_indent,
visitor_kind,
span,
);
self.push_rewrite(span, rewrite);
}
fn visit_assoc_item(&mut self, visitor_kind: &ItemVisitorKind<'_>) {
use ItemVisitorKind::*;
// TODO(calebcartwright): Not sure the skip spans are correct
let (ai, skip_span, assoc_ctxt) = match visitor_kind {
AssocTraitItem(ai) => (*ai, ai.span(), visit::AssocCtxt::Trait),
AssocImplItem(ai) => (*ai, ai.span, visit::AssocCtxt::Impl),
_ => unreachable!(),
};
skip_out_of_file_lines_range_visitor!(self, ai.span);
if self.visit_attrs(&ai.attrs, ast::AttrStyle::Outer) {
self.push_skipped_with_span(ai.attrs.as_slice(), skip_span, skip_span);
return;
}
// TODO(calebcartwright): consider enabling box_patterns feature gate
match (&ai.kind, visitor_kind) {
(ast::AssocItemKind::Const(..), AssocTraitItem(_)) => {
self.visit_static(&StaticParts::from_trait_item(ai))
}
(ast::AssocItemKind::Const(..), AssocImplItem(_)) => {
self.visit_static(&StaticParts::from_impl_item(ai))
}
(ast::AssocItemKind::Fn(ref fn_kind), _) => {
let ast::Fn {
defaultness,
ref sig,
ref generics,
ref body,
} = **fn_kind;
if let Some(ref body) = body {
let inner_attrs = inner_attributes(&ai.attrs);
let fn_ctxt = visit::FnCtxt::Assoc(assoc_ctxt);
self.visit_fn(
visit::FnKind::Fn(fn_ctxt, ai.ident, sig, &ai.vis, generics, Some(body)),
&sig.decl,
ai.span,
defaultness,
Some(&inner_attrs),
);
} else {
let indent = self.block_indent;
let rewrite =
self.rewrite_required_fn(indent, ai.ident, sig, &ai.vis, generics, ai.span);
self.push_rewrite(ai.span, rewrite);
}
}
(ast::AssocItemKind::Type(ref ty_alias), _) => {
self.visit_ty_alias_kind(ty_alias, visitor_kind, ai.span);
}
(ast::AssocItemKind::MacCall(ref mac), _) => {
self.visit_mac(mac, Some(ai.ident), MacroPosition::Item);
}
_ => unreachable!(),
}
}
pub(crate) fn visit_trait_item(&mut self, ti: &ast::AssocItem) {
self.visit_assoc_item(&ItemVisitorKind::AssocTraitItem(ti));
}
pub(crate) fn visit_impl_item(&mut self, ii: &ast::AssocItem) {
self.visit_assoc_item(&ItemVisitorKind::AssocImplItem(ii));
}
fn visit_mac(&mut self, mac: &ast::MacCall, ident: Option<symbol::Ident>, pos: MacroPosition) {
skip_out_of_file_lines_range_visitor!(self, mac.span());
// 1 = ;
let shape = self.shape().saturating_sub_width(1);
let rewrite = self.with_context(|ctx| rewrite_macro(mac, ident, ctx, shape, pos));
// As of v638 of the rustc-ap-* crates, the associated span no longer includes
// the trailing semicolon. This determines the correct span to ensure scenarios
// with whitespace between the delimiters and trailing semi (i.e. `foo!(abc) ;`)
// are formatted correctly.
let (span, rewrite) = match macro_style(mac, &self.get_context()) {
Delimiter::Bracket | Delimiter::Parenthesis if MacroPosition::Item == pos => {
let search_span = mk_sp(mac.span().hi(), self.snippet_provider.end_pos());
let hi = self.snippet_provider.span_before(search_span, ";");
let target_span = mk_sp(mac.span().lo(), hi + BytePos(1));
let rewrite = rewrite.map(|rw| {
if !rw.ends_with(';') {
format!("{};", rw)
} else {
rw
}
});
(target_span, rewrite)
}
_ => (mac.span(), rewrite),
};
self.push_rewrite(span, rewrite);
}
pub(crate) fn push_str(&mut self, s: &str) {
self.line_number += count_newlines(s);
self.buffer.push_str(s);
}
#[allow(clippy::needless_pass_by_value)]
fn push_rewrite_inner(&mut self, span: Span, rewrite: Option<String>) {
if let Some(ref s) = rewrite {
self.push_str(s);
} else {
let snippet = self.snippet(span);
self.push_str(snippet.trim());
}
self.last_pos = source!(self, span).hi();
}
pub(crate) fn push_rewrite(&mut self, span: Span, rewrite: Option<String>) {
self.format_missing_with_indent(source!(self, span).lo());
self.push_rewrite_inner(span, rewrite);
}
pub(crate) fn push_skipped_with_span(
&mut self,
attrs: &[ast::Attribute],
item_span: Span,
main_span: Span,
) {
self.format_missing_with_indent(source!(self, item_span).lo());
// do not take into account the lines with attributes as part of the skipped range
let attrs_end = attrs
.iter()
.map(|attr| self.parse_sess.line_of_byte_pos(attr.span.hi()))
.max()
.unwrap_or(1);
let first_line = self.parse_sess.line_of_byte_pos(main_span.lo());
// Statement can start after some newlines and/or spaces
// or it can be on the same line as the last attribute.
// So here we need to take a minimum between the two.
let lo = std::cmp::min(attrs_end + 1, first_line);
self.push_rewrite_inner(item_span, None);
let hi = self.line_number + 1;
self.skipped_range.borrow_mut().push((lo, hi));
}
pub(crate) fn from_context(ctx: &'a RewriteContext<'_>) -> FmtVisitor<'a> {
let mut visitor = FmtVisitor::from_parse_sess(
ctx.parse_sess,
ctx.config,
ctx.snippet_provider,
ctx.report.clone(),
);
visitor.skip_context.update(ctx.skip_context.clone());
visitor.set_parent_context(ctx);
visitor
}
pub(crate) fn from_parse_sess(
parse_session: &'a ParseSess,
config: &'a Config,
snippet_provider: &'a SnippetProvider,
report: FormatReport,
) -> FmtVisitor<'a> {
let mut skip_context = SkipContext::default();
let mut macro_names = Vec::new();
for macro_selector in config.skip_macro_invocations().0 {
match macro_selector {
MacroSelector::Name(name) => macro_names.push(name.to_string()),
MacroSelector::All => skip_context.macros.skip_all(),
}
}
skip_context.macros.extend(macro_names);
FmtVisitor {
parent_context: None,
parse_sess: parse_session,
buffer: String::with_capacity(snippet_provider.big_snippet.len() * 2),
last_pos: BytePos(0),
block_indent: Indent::empty(),
config,
is_if_else_block: false,
snippet_provider,
line_number: 0,
skipped_range: Rc::new(RefCell::new(vec![])),
is_macro_def: false,
macro_rewrite_failure: false,
report,
skip_context,
}
}
pub(crate) fn opt_snippet(&'b self, span: Span) -> Option<&'a str> {
self.snippet_provider.span_to_snippet(span)
}
pub(crate) fn snippet(&'b self, span: Span) -> &'a str {
self.opt_snippet(span).unwrap()
}
// Returns true if we should skip the following item.
pub(crate) fn visit_attrs(&mut self, attrs: &[ast::Attribute], style: ast::AttrStyle) -> bool {
for attr in attrs {
if attr.has_name(depr_skip_annotation()) {
let file_name = self.parse_sess.span_to_filename(attr.span);
self.report.append(
file_name,
vec![FormattingError::from_span(
attr.span,
self.parse_sess,
ErrorKind::DeprecatedAttr,
)],
);
} else {
match &attr.kind {
ast::AttrKind::Normal(ref normal)
if self.is_unknown_rustfmt_attr(&normal.item.path.segments) =>
{
let file_name = self.parse_sess.span_to_filename(attr.span);
self.report.append(
file_name,
vec![FormattingError::from_span(
attr.span,
self.parse_sess,
ErrorKind::BadAttr,
)],
);
}
_ => (),
}
}
}
if contains_skip(attrs) {
return true;
}
let attrs: Vec<_> = attrs.iter().filter(|a| a.style == style).cloned().collect();
if attrs.is_empty() {
return false;
}
let rewrite = attrs.rewrite(&self.get_context(), self.shape());
let span = mk_sp(attrs[0].span.lo(), attrs[attrs.len() - 1].span.hi());
self.push_rewrite(span, rewrite);
false
}
fn is_unknown_rustfmt_attr(&self, segments: &[ast::PathSegment]) -> bool {
if segments[0].ident.to_string() != "rustfmt" {
return false;
}
!is_skip_attr(segments)
}
fn walk_mod_items(&mut self, items: &[rustc_ast::ptr::P<ast::Item>]) {
self.visit_items_with_reordering(&ptr_vec_to_ref_vec(items));
}
fn walk_stmts(&mut self, stmts: &[Stmt<'_>], include_current_empty_semi: bool) {
if stmts.is_empty() {
return;
}
// Extract leading `use ...;`.
let items: Vec<_> = stmts
.iter()
.take_while(|stmt| stmt.to_item().map_or(false, is_use_item))
.filter_map(|stmt| stmt.to_item())
.collect();
if items.is_empty() {
self.visit_stmt(&stmts[0], include_current_empty_semi);
// FIXME(calebcartwright 2021-01-03) - This exists strictly to maintain legacy
// formatting where rustfmt would preserve redundant semicolons on Items in a
// statement position.
//
// Starting in rustc-ap-* v692 (~2020-12-01) the rustc parser now parses this as
// two separate statements (Item and Empty kinds), whereas before it was parsed as
// a single statement with the statement's span including the redundant semicolon.
//
// rustfmt typically tosses unnecessary/redundant semicolons, and eventually we
// should toss these as well, but doing so at this time would
// break the Stability Guarantee
// N.B. This could be updated to utilize the version gates.
let include_next_empty = if stmts.len() > 1 {
matches!(
(&stmts[0].as_ast_node().kind, &stmts[1].as_ast_node().kind),
(ast::StmtKind::Item(_), ast::StmtKind::Empty)
)
} else {
false
};
self.walk_stmts(&stmts[1..], include_next_empty);
} else {
self.visit_items_with_reordering(&items);
self.walk_stmts(&stmts[items.len()..], false);
}
}
fn walk_block_stmts(&mut self, b: &ast::Block) {
self.walk_stmts(&Stmt::from_ast_nodes(b.stmts.iter()), false)
}
fn format_mod(
&mut self,
mod_kind: &ast::ModKind,
unsafety: ast::Unsafe,
vis: &ast::Visibility,
s: Span,
ident: symbol::Ident,
attrs: &[ast::Attribute],
) {
let vis_str = utils::format_visibility(&self.get_context(), vis);
self.push_str(&*vis_str);
self.push_str(format_unsafety(unsafety));
self.push_str("mod ");
// Calling `to_owned()` to work around borrow checker.
let ident_str = rewrite_ident(&self.get_context(), ident).to_owned();
self.push_str(&ident_str);
if let ast::ModKind::Loaded(ref items, ast::Inline::Yes, ref spans) = mod_kind {
let ast::ModSpans {
inner_span,
inject_use_span: _,
} = *spans;
match self.config.brace_style() {
BraceStyle::AlwaysNextLine => {
let indent_str = self.block_indent.to_string_with_newline(self.config);
self.push_str(&indent_str);
self.push_str("{");
}
_ => self.push_str(" {"),
}
// Hackery to account for the closing }.
let mod_lo = self.snippet_provider.span_after(source!(self, s), "{");
let body_snippet =
self.snippet(mk_sp(mod_lo, source!(self, inner_span).hi() - BytePos(1)));
let body_snippet = body_snippet.trim();
if body_snippet.is_empty() {
self.push_str("}");
} else {
self.last_pos = mod_lo;
self.block_indent = self.block_indent.block_indent(self.config);
self.visit_attrs(attrs, ast::AttrStyle::Inner);
self.walk_mod_items(items);
let missing_span = self.next_span(inner_span.hi() - BytePos(1));
self.close_block(missing_span, false);
}
self.last_pos = source!(self, inner_span).hi();
} else {
self.push_str(";");
self.last_pos = source!(self, s).hi();
}
}
pub(crate) fn format_separate_mod(&mut self, m: &Module<'_>, end_pos: BytePos) {
self.block_indent = Indent::empty();
let skipped = self.visit_attrs(m.attrs(), ast::AttrStyle::Inner);
assert!(
!skipped,
"Skipping module must be handled before reaching this line."
);
self.walk_mod_items(&m.items);
self.format_missing_with_indent(end_pos);
}
pub(crate) fn skip_empty_lines(&mut self, end_pos: BytePos) {
while let Some(pos) = self
.snippet_provider
.opt_span_after(self.next_span(end_pos), "\n")
{
if let Some(snippet) = self.opt_snippet(self.next_span(pos)) {
if snippet.trim().is_empty() {
self.last_pos = pos;
} else {
return;
}
}
}
}
pub(crate) fn with_context<F>(&mut self, f: F) -> Option<String>
where
F: Fn(&RewriteContext<'_>) -> Option<String>,
{
let context = self.get_context();
let result = f(&context);
self.macro_rewrite_failure |= context.macro_rewrite_failure.get();
result
}
pub(crate) fn get_context(&self) -> RewriteContext<'_> {
RewriteContext {
parse_sess: self.parse_sess,
config: self.config,
inside_macro: Rc::new(Cell::new(false)),
use_block: Cell::new(false),
is_if_else_block: Cell::new(false),
force_one_line_chain: Cell::new(false),
snippet_provider: self.snippet_provider,
macro_rewrite_failure: Cell::new(false),
is_macro_def: self.is_macro_def,
report: self.report.clone(),
skip_context: self.skip_context.clone(),
skipped_range: self.skipped_range.clone(),
}
}
}