//! .qux
//! ```
+use comment::{rewrite_comment, CharClasses, FullCodeCharKind, RichChar};
use config::IndentStyle;
use expr::rewrite_call;
+use lists::extract_pre_comment;
use macros::convert_try_mac;
use rewrite::{Rewrite, RewriteContext};
use shape::Shape;
-use spanned::Spanned;
+use source_map::SpanUtils;
use utils::{
- first_line_width, last_line_extendable, last_line_width, mk_sp, trimmed_last_line_width,
- wrap_str,
+ first_line_width, last_line_extendable, last_line_width, mk_sp, rewrite_ident,
+ trimmed_last_line_width, wrap_str,
};
use std::borrow::Cow;
use std::cmp::min;
-use std::iter;
-use syntax::codemap::Span;
+use syntax::source_map::{BytePos, Span};
use syntax::{ast, ptr};
pub fn rewrite_chain(expr: &ast::Expr, context: &RewriteContext, shape: Shape) -> Option<String> {
chain.rewrite(context, shape)
}
+#[derive(Debug)]
+enum CommentPosition {
+ Back,
+ Top,
+}
+
// An expression plus trailing `?`s to be formatted together.
#[derive(Debug)]
struct ChainItem {
- // FIXME: we can't use a reference here because to convert `try!` to `?` we
- // synthesise the AST node. However, I think we could use `Cow` and that
- // would remove a lot of cloning.
- expr: ast::Expr,
+ kind: ChainItemKind,
tries: usize,
+ span: Span,
}
-impl Rewrite for ChainItem {
- fn rewrite(&self, context: &RewriteContext, shape: Shape) -> Option<String> {
- let rewrite = self.expr.rewrite(context, shape.sub_width(self.tries)?)?;
- Some(format!("{}{}", rewrite, "?".repeat(self.tries)))
- }
+// FIXME: we can't use a reference here because to convert `try!` to `?` we
+// synthesise the AST node. However, I think we could use `Cow` and that
+// would remove a lot of cloning.
+#[derive(Debug)]
+enum ChainItemKind {
+ Parent(ast::Expr),
+ MethodCall(
+ ast::PathSegment,
+ Vec<ast::GenericArg>,
+ Vec<ptr::P<ast::Expr>>,
+ ),
+ StructField(ast::Ident),
+ TupleField(ast::Ident, bool),
+ Comment(String, CommentPosition),
}
-impl ChainItem {
- // Rewrite the last element in the chain `expr`. E.g., given `a.b.c` we rewrite
- // `.c` and any trailing `?`s.
- fn rewrite_postfix(&self, context: &RewriteContext, shape: Shape) -> Option<String> {
- let shape = shape.sub_width(self.tries)?;
- let mut rewrite = match self.expr.node {
+impl ChainItemKind {
+ fn is_block_like(&self, context: &RewriteContext, reps: &str) -> bool {
+ match self {
+ ChainItemKind::Parent(ref expr) => is_block_expr(context, expr, reps),
+ ChainItemKind::MethodCall(..)
+ | ChainItemKind::StructField(..)
+ | ChainItemKind::TupleField(..)
+ | ChainItemKind::Comment(..) => false,
+ }
+ }
+
+ fn is_tup_field_access(expr: &ast::Expr) -> bool {
+ match expr.node {
+ ast::ExprKind::Field(_, ref field) => {
+ field.name.to_string().chars().all(|c| c.is_digit(10))
+ }
+ _ => false,
+ }
+ }
+
+ fn from_ast(context: &RewriteContext, expr: &ast::Expr) -> (ChainItemKind, Span) {
+ let (kind, span) = match expr.node {
ast::ExprKind::MethodCall(ref segment, ref expressions) => {
- let types = match segment.args {
- Some(ref params) => match **params {
- ast::GenericArgs::AngleBracketed(ref data) => &data.args[..],
- _ => &[],
- },
- _ => &[],
+ let types = if let Some(ref generic_args) = segment.args {
+ if let ast::GenericArgs::AngleBracketed(ref data) = **generic_args {
+ data.args.clone()
+ } else {
+ vec![]
+ }
+ } else {
+ vec![]
};
- Self::rewrite_method_call(
- segment.ident,
- types,
- expressions,
- self.expr.span,
- context,
- shape,
- )?
+ let span = mk_sp(expressions[0].span.hi(), expr.span.hi());
+ let kind = ChainItemKind::MethodCall(segment.clone(), types, expressions.clone());
+ (kind, span)
}
- ast::ExprKind::Field(ref nested, ref field) => {
- let space =
- if Self::is_tup_field_access(&self.expr) && Self::is_tup_field_access(nested) {
- " "
- } else {
- ""
- };
- let result = format!("{}.{}", space, field.name);
- if result.len() <= shape.width {
- result
+ ast::ExprKind::Field(ref nested, field) => {
+ let kind = if Self::is_tup_field_access(expr) {
+ ChainItemKind::TupleField(field, Self::is_tup_field_access(nested))
} else {
- return None;
- }
+ ChainItemKind::StructField(field)
+ };
+ let span = mk_sp(nested.span.hi(), field.span.hi());
+ (kind, span)
}
- _ => unreachable!(),
+ _ => return (ChainItemKind::Parent(expr.clone()), expr.span),
};
- rewrite.push_str(&"?".repeat(self.tries));
- Some(rewrite)
+
+ // Remove comments from the span.
+ let lo = context.snippet_provider.span_before(span, ".");
+ (kind, mk_sp(lo, span.hi()))
}
+}
- fn is_tup_field_access(expr: &ast::Expr) -> bool {
- match expr.node {
- ast::ExprKind::Field(_, ref field) => {
- field.name.to_string().chars().all(|c| c.is_digit(10))
+impl Rewrite for ChainItem {
+ fn rewrite(&self, context: &RewriteContext, shape: Shape) -> Option<String> {
+ let shape = shape.sub_width(self.tries)?;
+ let rewrite = match self.kind {
+ ChainItemKind::Parent(ref expr) => expr.rewrite(context, shape)?,
+ ChainItemKind::MethodCall(ref segment, ref types, ref exprs) => {
+ Self::rewrite_method_call(segment.ident, types, exprs, self.span, context, shape)?
+ }
+ ChainItemKind::StructField(ident) => format!(".{}", rewrite_ident(context, ident)),
+ ChainItemKind::TupleField(ident, nested) => format!(
+ "{}.{}",
+ if nested { " " } else { "" },
+ rewrite_ident(context, ident)
+ ),
+ ChainItemKind::Comment(ref comment, _) => {
+ rewrite_comment(comment, false, shape, context.config)?
}
+ };
+ Some(format!("{}{}", rewrite, "?".repeat(self.tries)))
+ }
+}
+
+impl ChainItem {
+ fn new(context: &RewriteContext, expr: &ast::Expr, tries: usize) -> ChainItem {
+ let (kind, span) = ChainItemKind::from_ast(context, expr);
+ ChainItem { kind, tries, span }
+ }
+
+ fn comment(span: Span, comment: String, pos: CommentPosition) -> ChainItem {
+ ChainItem {
+ kind: ChainItemKind::Comment(comment, pos),
+ tries: 0,
+ span,
+ }
+ }
+
+ fn is_comment(&self) -> bool {
+ match self.kind {
+ ChainItemKind::Comment(..) => true,
_ => false,
}
}
context: &RewriteContext,
shape: Shape,
) -> Option<String> {
- let (lo, type_str) = if types.is_empty() {
- (args[0].span.hi(), String::new())
+ let type_str = if types.is_empty() {
+ String::new()
} else {
let type_list = types
.iter()
.map(|ty| ty.rewrite(context, shape))
.collect::<Option<Vec<_>>>()?;
- let type_str = format!("::<{}>", type_list.join(", "));
-
- (types.last().unwrap().span().hi(), type_str)
+ format!("::<{}>", type_list.join(", "))
};
-
- let callee_str = format!(".{}{}", method_name, type_str);
- let span = mk_sp(lo, span.hi());
-
+ let callee_str = format!(".{}{}", rewrite_ident(context, method_name), type_str);
rewrite_call(context, &callee_str, &args[1..], span, shape)
}
}
let subexpr_list = Self::make_subexpr_list(expr, context);
// Un-parse the expression tree into ChainItems
- let mut children = vec![];
+ let mut rev_children = vec![];
let mut sub_tries = 0;
- for subexpr in subexpr_list {
+ for subexpr in &subexpr_list {
match subexpr.node {
ast::ExprKind::Try(_) => sub_tries += 1,
_ => {
- children.push(ChainItem {
- expr: subexpr,
- tries: sub_tries,
- });
+ rev_children.push(ChainItem::new(context, subexpr, sub_tries));
sub_tries = 0;
}
}
}
- Chain {
- parent: children.pop().unwrap(),
- children,
+ fn is_tries(s: &str) -> bool {
+ s.chars().all(|c| c == '?')
}
+
+ fn is_post_comment(s: &str) -> bool {
+ let comment_start_index = s.chars().position(|c| c == '/');
+ if comment_start_index.is_none() {
+ return false;
+ }
+
+ let newline_index = s.chars().position(|c| c == '\n');
+ if newline_index.is_none() {
+ return true;
+ }
+
+ comment_start_index.unwrap() < newline_index.unwrap()
+ }
+
+ fn handle_post_comment(
+ post_comment_span: Span,
+ post_comment_snippet: &str,
+ prev_span_end: &mut BytePos,
+ children: &mut Vec<ChainItem>,
+ ) {
+ let white_spaces: &[_] = &[' ', '\t'];
+ if post_comment_snippet
+ .trim_matches(white_spaces)
+ .starts_with('\n')
+ {
+ // No post comment.
+ return;
+ }
+ let trimmed_snippet = trim_tries(post_comment_snippet);
+ if is_post_comment(&trimmed_snippet) {
+ children.push(ChainItem::comment(
+ post_comment_span,
+ trimmed_snippet.trim().to_owned(),
+ CommentPosition::Back,
+ ));
+ *prev_span_end = post_comment_span.hi();
+ }
+ }
+
+ let parent = rev_children.pop().unwrap();
+ let mut children = vec![];
+ let mut prev_span_end = parent.span.hi();
+ let mut iter = rev_children.into_iter().rev().peekable();
+ if let Some(first_chain_item) = iter.peek() {
+ let comment_span = mk_sp(prev_span_end, first_chain_item.span.lo());
+ let comment_snippet = context.snippet(comment_span);
+ if !is_tries(comment_snippet.trim()) {
+ handle_post_comment(
+ comment_span,
+ comment_snippet,
+ &mut prev_span_end,
+ &mut children,
+ );
+ }
+ }
+ while let Some(chain_item) = iter.next() {
+ let comment_snippet = context.snippet(chain_item.span);
+ // FIXME: Figure out the way to get a correct span when converting `try!` to `?`.
+ let handle_comment =
+ !(context.config.use_try_shorthand() || is_tries(comment_snippet.trim()));
+
+ // Pre-comment
+ if handle_comment {
+ let pre_comment_span = mk_sp(prev_span_end, chain_item.span.lo());
+ let pre_comment_snippet = trim_tries(context.snippet(pre_comment_span));
+ let (pre_comment, _) = extract_pre_comment(&pre_comment_snippet);
+ match pre_comment {
+ Some(ref comment) if !comment.is_empty() => {
+ children.push(ChainItem::comment(
+ pre_comment_span,
+ comment.to_owned(),
+ CommentPosition::Top,
+ ));
+ }
+ _ => (),
+ }
+ }
+
+ prev_span_end = chain_item.span.hi();
+ children.push(chain_item);
+
+ // Post-comment
+ if !handle_comment || iter.peek().is_none() {
+ continue;
+ }
+
+ let next_lo = iter.peek().unwrap().span.lo();
+ let post_comment_span = mk_sp(prev_span_end, next_lo);
+ let post_comment_snippet = context.snippet(post_comment_span);
+ handle_post_comment(
+ post_comment_span,
+ post_comment_snippet,
+ &mut prev_span_end,
+ &mut children,
+ );
+ }
+
+ Chain { parent, children }
}
// Returns a Vec of the prefixes of the chain.
shape: Shape,
child_shape: Shape,
) -> Option<()> {
- let last = &self.children[0];
- let extendable =
- may_extend && last_line_extendable(&self.rewrites[self.rewrites.len() - 1]);
- let prev_last_line_width = last_line_width(&self.rewrites[self.rewrites.len() - 1]);
+ let last = self.children.last()?;
+ let extendable = may_extend && last_line_extendable(&self.rewrites[0]);
+ let prev_last_line_width = last_line_width(&self.rewrites[0]);
// Total of all items excluding the last.
let almost_total = if extendable {
shape.width
} else {
min(shape.width, context.config.width_heuristics().chain_width)
- }.saturating_sub(almost_total);
+ }
+ .saturating_sub(almost_total);
- let all_in_one_line =
- self.rewrites.iter().all(|s| !s.contains('\n')) && one_line_budget > 0;
+ let all_in_one_line = !self.children.iter().any(ChainItem::is_comment)
+ && self.rewrites.iter().all(|s| !s.contains('\n'))
+ && one_line_budget > 0;
let last_shape = if all_in_one_line {
shape.sub_width(last.tries)?
} else if extendable {
if all_in_one_line || extendable {
// First we try to 'overflow' the last child and see if it looks better than using
// vertical layout.
- if let Some(one_line_shape) = last_shape.offset_left(almost_total) {
- if let Some(rw) = last.rewrite_postfix(context, one_line_shape) {
+ let one_line_shape = if context.use_block_indent() {
+ last_shape.offset_left(almost_total)
+ } else {
+ last_shape
+ .visual_indent(almost_total)
+ .sub_width(almost_total)
+ };
+
+ if let Some(one_line_shape) = one_line_shape {
+ if let Some(rw) = last.rewrite(context, one_line_shape) {
// We allow overflowing here only if both of the following conditions match:
// 1. The entire chain fits in a single line except the last child.
// 2. `last_child_str.lines().count() >= 5`.
// better.
let last_shape = child_shape
.sub_width(shape.rhs_overhead(context.config) + last.tries)?;
- match last.rewrite_postfix(context, last_shape) {
+ match last.rewrite(context, last_shape) {
Some(ref new_rw) if !could_fit_single_line => {
last_subexpr_str = Some(new_rw.clone());
}
}
}
- last_subexpr_str = last_subexpr_str.or_else(|| last.rewrite_postfix(context, last_shape));
+ let last_shape = if context.use_block_indent() {
+ last_shape
+ } else {
+ child_shape.sub_width(shape.rhs_overhead(context.config) + last.tries)?
+ };
+
+ last_subexpr_str = last_subexpr_str.or_else(|| last.rewrite(context, last_shape));
self.rewrites.push(last_subexpr_str?);
Some(())
}
- fn join_rewrites(
- &self,
- context: &RewriteContext,
- child_shape: Shape,
- block_like_iter: impl Iterator<Item = bool>,
- ) -> Option<String> {
+ fn join_rewrites(&self, context: &RewriteContext, child_shape: Shape) -> Option<String> {
let connector = if self.fits_single_line {
// Yay, we can put everything on one line.
Cow::from("")
let mut rewrite_iter = self.rewrites.iter();
let mut result = rewrite_iter.next().unwrap().clone();
-
- for (rewrite, prev_is_block_like) in rewrite_iter.zip(block_like_iter) {
- if !prev_is_block_like {
- result.push_str(&connector);
+ let children_iter = self.children.iter();
+ let iter = rewrite_iter.zip(children_iter);
+
+ for (rewrite, chain_item) in iter {
+ match chain_item.kind {
+ ChainItemKind::Comment(_, CommentPosition::Back) => result.push(' '),
+ ChainItemKind::Comment(_, CommentPosition::Top) => result.push_str(&connector),
+ _ => result.push_str(&connector),
}
result.push_str(&rewrite);
}
// Formats a chain using block indent.
struct ChainFormatterBlock<'a> {
shared: ChainFormatterShared<'a>,
- // For each rewrite, whether the corresponding item is block-like.
- is_block_like: Vec<bool>,
+ root_ends_with_block: bool,
}
impl<'a> ChainFormatterBlock<'a> {
fn new(chain: &'a Chain) -> ChainFormatterBlock<'a> {
ChainFormatterBlock {
shared: ChainFormatterShared::new(chain),
- is_block_like: Vec::with_capacity(chain.children.len() + 1),
+ root_ends_with_block: false,
}
}
}
) -> Option<()> {
let mut root_rewrite: String = parent.rewrite(context, shape)?;
- let mut root_ends_with_block = is_block_expr(context, &parent.expr, &root_rewrite);
+ let mut root_ends_with_block = parent.kind.is_block_like(context, &root_rewrite);
let tab_width = context.config.tab_spaces().saturating_sub(shape.offset);
while root_rewrite.len() <= tab_width && !root_rewrite.contains('\n') {
- let item = &self.shared.children[self.shared.children.len() - 1];
+ let item = &self.shared.children[0];
+ if let ChainItemKind::Comment(..) = item.kind {
+ break;
+ }
let shape = shape.offset_left(root_rewrite.len())?;
- match &item.rewrite_postfix(context, shape) {
+ match &item.rewrite(context, shape) {
Some(rewrite) => root_rewrite.push_str(rewrite),
None => break,
}
- root_ends_with_block = is_block_expr(context, &item.expr, &root_rewrite);
+ root_ends_with_block = last_line_extendable(&root_rewrite);
- self.shared.children = &self.shared.children[..self.shared.children.len() - 1];
+ self.shared.children = &self.shared.children[1..];
if self.shared.children.is_empty() {
break;
}
}
- self.is_block_like.push(root_ends_with_block);
self.shared.rewrites.push(root_rewrite);
+ self.root_ends_with_block = root_ends_with_block;
Some(())
}
fn child_shape(&self, context: &RewriteContext, shape: Shape) -> Option<Shape> {
Some(
- if self.is_block_like[0] {
+ if self.root_ends_with_block {
shape.block_indent(0)
} else {
shape.block_indent(context.config.tab_spaces())
- }.with_max_width(context.config),
+ }
+ .with_max_width(context.config),
)
}
fn format_children(&mut self, context: &RewriteContext, child_shape: Shape) -> Option<()> {
- for item in self.shared.children[1..].iter().rev() {
- let rewrite = item.rewrite_postfix(context, child_shape)?;
- self.is_block_like
- .push(is_block_expr(context, &item.expr, &rewrite));
+ for item in &self.shared.children[..self.shared.children.len() - 1] {
+ let rewrite = item.rewrite(context, child_shape)?;
self.shared.rewrites.push(rewrite);
}
Some(())
}
fn join_rewrites(&self, context: &RewriteContext, child_shape: Shape) -> Option<String> {
- self.shared
- .join_rewrites(context, child_shape, self.is_block_like.iter().cloned())
+ self.shared.join_rewrites(context, child_shape)
}
fn pure_root(&mut self) -> Option<String> {
trimmed_last_line_width(&root_rewrite)
};
- if !multiline || is_block_expr(context, &parent.expr, &root_rewrite) {
- let item = &self.shared.children[self.shared.children.len() - 1];
+ if !multiline || parent.kind.is_block_like(context, &root_rewrite) {
+ let item = &self.shared.children[0];
+ if let ChainItemKind::Comment(..) = item.kind {
+ self.shared.rewrites.push(root_rewrite);
+ return Some(());
+ }
let child_shape = parent_shape
.visual_indent(self.offset)
.sub_width(self.offset)?;
- let rewrite = item.rewrite_postfix(context, child_shape)?;
+ let rewrite = item.rewrite(context, child_shape)?;
match wrap_str(rewrite, context.config.max_width(), shape) {
Some(rewrite) => root_rewrite.push_str(&rewrite),
None => {
// We couldn't fit in at the visual indent, try the last
// indent.
- let rewrite = item.rewrite_postfix(context, parent_shape)?;
+ let rewrite = item.rewrite(context, parent_shape)?;
root_rewrite.push_str(&rewrite);
self.offset = 0;
}
}
- self.shared.children = &self.shared.children[..self.shared.children.len() - 1];
+ self.shared.children = &self.shared.children[1..];
}
self.shared.rewrites.push(root_rewrite);
}
fn format_children(&mut self, context: &RewriteContext, child_shape: Shape) -> Option<()> {
- for item in self.shared.children[1..].iter().rev() {
- let rewrite = item.rewrite_postfix(context, child_shape)?;
+ for item in &self.shared.children[..self.shared.children.len() - 1] {
+ let rewrite = item.rewrite(context, child_shape)?;
self.shared.rewrites.push(rewrite);
}
Some(())
}
fn join_rewrites(&self, context: &RewriteContext, child_shape: Shape) -> Option<String> {
- self.shared
- .join_rewrites(context, child_shape, iter::repeat(false))
+ self.shared.join_rewrites(context, child_shape)
}
fn pure_root(&mut self) -> Option<String> {
ast::ExprKind::Mac(..)
| ast::ExprKind::Call(..)
| ast::ExprKind::MethodCall(..)
+ | ast::ExprKind::Array(..)
| ast::ExprKind::Struct(..)
| ast::ExprKind::While(..)
| ast::ExprKind::WhileLet(..)
_ => false,
}
}
+
+/// Remove try operators (`?`s) that appear in the given string. If removing
+/// them leaves an empty line, remove that line as well unless it is the first
+/// line (we need the first newline for detecting pre/post comment).
+fn trim_tries(s: &str) -> String {
+ let mut result = String::with_capacity(s.len());
+ let mut line_buffer = String::with_capacity(s.len());
+ for (kind, rich_char) in CharClasses::new(s.chars()) {
+ match rich_char.get_char() {
+ '\n' => {
+ if result.is_empty() || !line_buffer.trim().is_empty() {
+ result.push_str(&line_buffer);
+ result.push('\n')
+ }
+ line_buffer.clear();
+ }
+ '?' if kind == FullCodeCharKind::Normal => continue,
+ c => line_buffer.push(c),
+ }
+ }
+ if !line_buffer.trim().is_empty() {
+ result.push_str(&line_buffer);
+ }
+ result
+}
projects / rust.git / blobdiff