521 lines
18 KiB
Rust
521 lines
18 KiB
Rust
// Copyright 2015 The Rust Project Developers. See the COPYRIGHT
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// file at the top-level directory of this distribution and at
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// http://rust-lang.org/COPYRIGHT.
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//
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// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
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// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
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// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
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// option. This file may not be copied, modified, or distributed
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// except according to those terms.
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use std::cmp;
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use std::iter::Peekable;
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use syntax::codemap::{self, CodeMap, BytePos};
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use Indent;
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use comment::{FindUncommented, rewrite_comment, find_comment_end};
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use config::Config;
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#[derive(Eq, PartialEq, Debug, Copy, Clone)]
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/// Formatting tactic for lists. This will be cast down to a
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/// DefinitiveListTactic depending on the number and length of the items and
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/// their comments.
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pub enum ListTactic {
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// One item per row.
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Vertical,
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// All items on one row.
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Horizontal,
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// Try Horizontal layout, if that fails then vertical.
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HorizontalVertical,
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// HorizontalVertical with a soft limit of n characters.
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LimitedHorizontalVertical(usize),
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// Pack as many items as possible per row over (possibly) many rows.
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Mixed,
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}
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impl_enum_decodable!(ListTactic, Vertical, Horizontal, HorizontalVertical, Mixed);
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#[derive(Eq, PartialEq, Debug, Copy, Clone)]
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pub enum SeparatorTactic {
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Always,
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Never,
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Vertical,
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}
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impl_enum_decodable!(SeparatorTactic, Always, Never, Vertical);
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impl SeparatorTactic {
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pub fn from_bool(b: bool) -> SeparatorTactic {
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if b {
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SeparatorTactic::Always
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} else {
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SeparatorTactic::Never
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}
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}
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}
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pub struct ListFormatting<'a> {
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pub tactic: DefinitiveListTactic,
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pub separator: &'a str,
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pub trailing_separator: SeparatorTactic,
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pub indent: Indent,
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pub width: usize,
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// Non-expressions, e.g. items, will have a new line at the end of the list.
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// Important for comment styles.
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pub ends_with_newline: bool,
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pub config: &'a Config,
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}
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pub fn format_fn_args<I>(items: I, width: usize, offset: Indent, config: &Config) -> Option<String>
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where I: Iterator<Item = ListItem>
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{
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list_helper(items,
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width,
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offset,
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config,
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ListTactic::LimitedHorizontalVertical(config.fn_call_width))
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}
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pub fn format_item_list<I>(items: I,
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width: usize,
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offset: Indent,
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config: &Config)
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-> Option<String>
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where I: Iterator<Item = ListItem>
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{
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list_helper(items, width, offset, config, ListTactic::HorizontalVertical)
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}
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pub fn list_helper<I>(items: I,
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width: usize,
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offset: Indent,
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config: &Config,
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tactic: ListTactic)
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-> Option<String>
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where I: Iterator<Item = ListItem>
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{
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let item_vec: Vec<_> = items.collect();
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let tactic = definitive_tactic(&item_vec, tactic, width);
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let fmt = ListFormatting {
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tactic: tactic,
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separator: ",",
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trailing_separator: SeparatorTactic::Never,
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indent: offset,
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width: width,
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ends_with_newline: false,
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config: config,
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};
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write_list(&item_vec, &fmt)
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}
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impl AsRef<ListItem> for ListItem {
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fn as_ref(&self) -> &ListItem {
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self
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}
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}
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pub struct ListItem {
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// None for comments mean that they are not present.
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pub pre_comment: Option<String>,
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// Item should include attributes and doc comments. None indicates a failed
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// rewrite.
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pub item: Option<String>,
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pub post_comment: Option<String>,
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// Whether there is extra whitespace before this item.
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pub new_lines: bool,
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}
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impl ListItem {
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pub fn is_multiline(&self) -> bool {
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self.item.as_ref().map_or(false, |s| s.contains('\n')) || self.pre_comment.is_some() ||
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self.post_comment.as_ref().map_or(false, |s| s.contains('\n'))
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}
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pub fn has_line_pre_comment(&self) -> bool {
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self.pre_comment.as_ref().map_or(false, |comment| comment.starts_with("//"))
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}
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pub fn from_str<S: Into<String>>(s: S) -> ListItem {
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ListItem {
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pre_comment: None,
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item: Some(s.into()),
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post_comment: None,
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new_lines: false,
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}
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}
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}
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#[derive(Eq, PartialEq, Debug, Copy, Clone)]
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/// The definitive formatting tactic for lists.
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pub enum DefinitiveListTactic {
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Vertical,
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Horizontal,
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Mixed,
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}
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pub fn definitive_tactic<I, T>(items: I, tactic: ListTactic, width: usize) -> DefinitiveListTactic
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where I: IntoIterator<Item = T> + Clone,
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T: AsRef<ListItem>
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{
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let pre_line_comments = items.clone()
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.into_iter()
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.any(|item| item.as_ref().has_line_pre_comment());
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let limit = match tactic {
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_ if pre_line_comments => return DefinitiveListTactic::Vertical,
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ListTactic::Mixed => return DefinitiveListTactic::Mixed,
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ListTactic::Horizontal => return DefinitiveListTactic::Horizontal,
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ListTactic::Vertical => return DefinitiveListTactic::Vertical,
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ListTactic::LimitedHorizontalVertical(limit) => ::std::cmp::min(width, limit),
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ListTactic::HorizontalVertical => width,
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};
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let (sep_count, total_width) = calculate_width(items.clone());
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let sep_len = ", ".len(); // FIXME: make more generic?
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let total_sep_len = sep_len * sep_count.checked_sub(1).unwrap_or(0);
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let real_total = total_width + total_sep_len;
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if real_total <= limit && !pre_line_comments &&
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!items.into_iter().any(|item| item.as_ref().is_multiline()) {
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DefinitiveListTactic::Horizontal
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} else {
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DefinitiveListTactic::Vertical
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}
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}
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// Format a list of commented items into a string.
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// TODO: add unit tests
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pub fn write_list<I, T>(items: I, formatting: &ListFormatting) -> Option<String>
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where I: IntoIterator<Item = T>,
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T: AsRef<ListItem>
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{
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let tactic = formatting.tactic;
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let sep_len = formatting.separator.len();
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// Now that we know how we will layout, we can decide for sure if there
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// will be a trailing separator.
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let trailing_separator = needs_trailing_separator(formatting.trailing_separator, tactic);
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let mut result = String::new();
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let mut iter = items.into_iter().enumerate().peekable();
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let mut line_len = 0;
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let indent_str = &formatting.indent.to_string(formatting.config);
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while let Some((i, item)) = iter.next() {
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let item = item.as_ref();
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let inner_item = try_opt!(item.item.as_ref());
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let first = i == 0;
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let last = iter.peek().is_none();
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let separate = !last || trailing_separator;
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let item_sep_len = if separate {
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sep_len
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} else {
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0
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};
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// Item string may be multi-line. Its length (used for block comment alignment)
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// Should be only the length of the last line.
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let item_last_line = if item.is_multiline() {
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inner_item.lines().last().unwrap_or("")
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} else {
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inner_item.as_ref()
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};
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let mut item_last_line_width = item_last_line.len() + item_sep_len;
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if item_last_line.starts_with(indent_str) {
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item_last_line_width -= indent_str.len();
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}
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match tactic {
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DefinitiveListTactic::Horizontal if !first => {
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result.push(' ');
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}
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DefinitiveListTactic::Vertical if !first => {
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result.push('\n');
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result.push_str(indent_str);
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}
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DefinitiveListTactic::Mixed => {
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let total_width = total_item_width(item) + item_sep_len;
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// 1 is space between separator and item.
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if line_len > 0 && line_len + 1 + total_width > formatting.width {
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result.push('\n');
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result.push_str(indent_str);
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line_len = 0;
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}
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if line_len > 0 {
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result.push(' ');
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line_len += 1;
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}
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line_len += total_width;
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}
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_ => {}
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}
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// Pre-comments
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if let Some(ref comment) = item.pre_comment {
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// Block style in non-vertical mode.
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let block_mode = tactic != DefinitiveListTactic::Vertical;
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// Width restriction is only relevant in vertical mode.
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let max_width = formatting.width;
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let comment = try_opt!(rewrite_comment(comment,
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block_mode,
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max_width,
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formatting.indent,
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formatting.config));
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result.push_str(&comment);
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if tactic == DefinitiveListTactic::Vertical {
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result.push('\n');
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result.push_str(indent_str);
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} else {
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result.push(' ');
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}
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}
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result.push_str(&inner_item[..]);
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// Post-comments
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if tactic != DefinitiveListTactic::Vertical && item.post_comment.is_some() {
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let comment = item.post_comment.as_ref().unwrap();
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let formatted_comment = try_opt!(rewrite_comment(comment,
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true,
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formatting.width,
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Indent::empty(),
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formatting.config));
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result.push(' ');
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result.push_str(&formatted_comment);
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}
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if separate {
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result.push_str(formatting.separator);
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}
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if tactic == DefinitiveListTactic::Vertical && item.post_comment.is_some() {
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// 1 = space between item and comment.
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let width = formatting.width.checked_sub(item_last_line_width + 1).unwrap_or(1);
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let mut offset = formatting.indent;
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offset.alignment += item_last_line_width + 1;
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let comment = item.post_comment.as_ref().unwrap();
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debug!("Width = {}, offset = {:?}", width, offset);
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// Use block-style only for the last item or multiline comments.
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let block_style = !formatting.ends_with_newline && last ||
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comment.trim().contains('\n') ||
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comment.trim().len() > width;
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let formatted_comment = try_opt!(rewrite_comment(comment,
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block_style,
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width,
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offset,
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formatting.config));
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result.push(' ');
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result.push_str(&formatted_comment);
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}
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if !last && tactic == DefinitiveListTactic::Vertical && item.new_lines {
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result.push('\n');
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}
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}
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Some(result)
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}
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pub struct ListItems<'a, I, F1, F2, F3>
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where I: Iterator
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{
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codemap: &'a CodeMap,
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inner: Peekable<I>,
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get_lo: F1,
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get_hi: F2,
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get_item_string: F3,
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prev_span_end: BytePos,
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next_span_start: BytePos,
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terminator: &'a str,
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}
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impl<'a, T, I, F1, F2, F3> Iterator for ListItems<'a, I, F1, F2, F3>
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where I: Iterator<Item = T>,
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F1: Fn(&T) -> BytePos,
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F2: Fn(&T) -> BytePos,
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F3: Fn(&T) -> Option<String>
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{
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type Item = ListItem;
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fn next(&mut self) -> Option<Self::Item> {
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let white_space: &[_] = &[' ', '\t'];
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self.inner.next().map(|item| {
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let mut new_lines = false;
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// Pre-comment
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let pre_snippet = self.codemap
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.span_to_snippet(codemap::mk_sp(self.prev_span_end,
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(self.get_lo)(&item)))
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.unwrap();
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let trimmed_pre_snippet = pre_snippet.trim();
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let pre_comment = if !trimmed_pre_snippet.is_empty() {
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Some(trimmed_pre_snippet.to_owned())
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} else {
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None
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};
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// Post-comment
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let next_start = match self.inner.peek() {
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Some(ref next_item) => (self.get_lo)(next_item),
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None => self.next_span_start,
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};
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let post_snippet = self.codemap
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.span_to_snippet(codemap::mk_sp((self.get_hi)(&item),
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next_start))
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.unwrap();
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let comment_end = match self.inner.peek() {
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Some(..) => {
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let block_open_index = post_snippet.find("/*");
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let newline_index = post_snippet.find('\n');
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let separator_index = post_snippet.find_uncommented(",").unwrap();
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match (block_open_index, newline_index) {
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// Separator before comment, with the next item on same line.
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// Comment belongs to next item.
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(Some(i), None) if i > separator_index => separator_index + 1,
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// Block-style post-comment before the separator.
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(Some(i), None) => {
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cmp::max(find_comment_end(&post_snippet[i..]).unwrap() + i,
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separator_index + 1)
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}
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// Block-style post-comment. Either before or after the separator.
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(Some(i), Some(j)) if i < j => {
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cmp::max(find_comment_end(&post_snippet[i..]).unwrap() + i,
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separator_index + 1)
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}
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// Potential *single* line comment.
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(_, Some(j)) if j > separator_index => j + 1,
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_ => post_snippet.len(),
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}
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}
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None => {
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post_snippet.find_uncommented(self.terminator).unwrap_or(post_snippet.len())
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}
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};
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if !post_snippet.is_empty() && comment_end > 0 {
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// Account for extra whitespace between items. This is fiddly
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// because of the way we divide pre- and post- comments.
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// Everything from the separator to the next item.
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let test_snippet = &post_snippet[comment_end - 1..];
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let first_newline = test_snippet.find('\n').unwrap_or(test_snippet.len());
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// From the end of the first line of comments.
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let test_snippet = &test_snippet[first_newline..];
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let first = test_snippet.find(|c: char| !c.is_whitespace())
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.unwrap_or(test_snippet.len());
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// From the end of the first line of comments to the next non-whitespace char.
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let test_snippet = &test_snippet[..first];
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if test_snippet.chars().filter(|c| c == &'\n').count() > 1 {
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// There were multiple line breaks which got trimmed to nothing.
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new_lines = true;
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}
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}
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// Cleanup post-comment: strip separators and whitespace.
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self.prev_span_end = (self.get_hi)(&item) + BytePos(comment_end as u32);
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let post_snippet = post_snippet[..comment_end].trim();
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let post_snippet_trimmed = if post_snippet.starts_with(',') {
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post_snippet[1..].trim_matches(white_space)
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} else if post_snippet.ends_with(",") {
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post_snippet[..(post_snippet.len() - 1)].trim_matches(white_space)
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} else {
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post_snippet
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};
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let post_comment = if !post_snippet_trimmed.is_empty() {
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Some(post_snippet_trimmed.to_owned())
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} else {
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None
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};
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ListItem {
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pre_comment: pre_comment,
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item: (self.get_item_string)(&item),
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post_comment: post_comment,
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new_lines: new_lines,
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}
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})
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}
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}
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// Creates an iterator over a list's items with associated comments.
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pub fn itemize_list<'a, T, I, F1, F2, F3>(codemap: &'a CodeMap,
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inner: I,
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terminator: &'a str,
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get_lo: F1,
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get_hi: F2,
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get_item_string: F3,
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prev_span_end: BytePos,
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next_span_start: BytePos)
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-> ListItems<'a, I, F1, F2, F3>
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where I: Iterator<Item = T>,
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F1: Fn(&T) -> BytePos,
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F2: Fn(&T) -> BytePos,
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F3: Fn(&T) -> Option<String>
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{
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ListItems {
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codemap: codemap,
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inner: inner.peekable(),
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get_lo: get_lo,
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get_hi: get_hi,
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get_item_string: get_item_string,
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prev_span_end: prev_span_end,
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next_span_start: next_span_start,
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terminator: terminator,
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}
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}
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fn needs_trailing_separator(separator_tactic: SeparatorTactic,
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list_tactic: DefinitiveListTactic)
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-> bool {
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match separator_tactic {
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SeparatorTactic::Always => true,
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SeparatorTactic::Vertical => list_tactic == DefinitiveListTactic::Vertical,
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SeparatorTactic::Never => false,
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}
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}
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/// Returns the count and total width of the list items.
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fn calculate_width<I, T>(items: I) -> (usize, usize)
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where I: IntoIterator<Item = T>,
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T: AsRef<ListItem>
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{
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items.into_iter()
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.map(|item| total_item_width(item.as_ref()))
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.fold((0, 0), |acc, l| (acc.0 + 1, acc.1 + l))
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}
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fn total_item_width(item: &ListItem) -> usize {
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comment_len(item.pre_comment.as_ref().map(|x| &(*x)[..])) +
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comment_len(item.post_comment.as_ref().map(|x| &(*x)[..])) +
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item.item.as_ref().map_or(0, |str| str.len())
|
|
}
|
|
|
|
fn comment_len(comment: Option<&str>) -> usize {
|
|
match comment {
|
|
Some(s) => {
|
|
let text_len = s.trim().len();
|
|
if text_len > 0 {
|
|
// We'll put " /*" before and " */" after inline comments.
|
|
text_len + 6
|
|
} else {
|
|
text_len
|
|
}
|
|
}
|
|
None => 0,
|
|
}
|
|
}
|