671 lines
25 KiB
Rust
671 lines
25 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 rewrite::{Rewrite, RewriteContext};
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use lists::{write_list, itemize_list, ListFormatting, SeparatorTactic, ListTactic};
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use string::{StringFormat, rewrite_string};
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use StructLitStyle;
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use utils::{span_after, make_indent, extra_offset};
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use visitor::FmtVisitor;
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use config::BlockIndentStyle;
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use comment::{FindUncommented, rewrite_comment};
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use types::rewrite_path;
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use syntax::{ast, ptr};
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use syntax::codemap::{Pos, Span, BytePos, mk_sp};
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use syntax::visit::Visitor;
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impl Rewrite for ast::Expr {
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fn rewrite(&self, context: &RewriteContext, width: usize, offset: usize) -> Option<String> {
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match self.node {
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ast::Expr_::ExprLit(ref l) => {
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match l.node {
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ast::Lit_::LitStr(ref is, _) => {
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rewrite_string_lit(context, &is, l.span, width, offset)
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}
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_ => context.codemap.span_to_snippet(self.span).ok()
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}
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}
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ast::Expr_::ExprCall(ref callee, ref args) => {
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rewrite_call(context, callee, args, self.span, width, offset)
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}
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ast::Expr_::ExprParen(ref subexpr) => {
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rewrite_paren(context, subexpr, width, offset)
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}
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ast::Expr_::ExprBinary(ref op, ref lhs, ref rhs) => {
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rewrite_binary_op(context, op, lhs, rhs, width, offset)
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}
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ast::Expr_::ExprUnary(ref op, ref subexpr) => {
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rewrite_unary_op(context, op, subexpr, width, offset)
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}
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ast::Expr_::ExprStruct(ref path, ref fields, ref base) => {
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rewrite_struct_lit(context,
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path,
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fields,
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base.as_ref().map(|e| &**e),
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self.span,
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width,
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offset)
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}
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ast::Expr_::ExprTup(ref items) => {
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rewrite_tuple_lit(context, items, self.span, width, offset)
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}
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ast::Expr_::ExprWhile(ref cond, ref block, label) => {
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Loop::new_while(None, cond, block, label).rewrite(context, width, offset)
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}
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ast::Expr_::ExprWhileLet(ref pat, ref cond, ref block, label) => {
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Loop::new_while(Some(pat), cond, block, label).rewrite(context, width, offset)
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}
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ast::Expr_::ExprForLoop(ref pat, ref cond, ref block, label) => {
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Loop::new_for(pat, cond, block, label).rewrite(context, width, offset)
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}
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ast::Expr_::ExprLoop(ref block, label) => {
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Loop::new_loop(block, label).rewrite(context, width, offset)
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}
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ast::Expr_::ExprBlock(ref block) => {
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block.rewrite(context, width, offset)
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}
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ast::Expr_::ExprIf(ref cond, ref if_block, ref else_block) => {
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rewrite_if_else(context,
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cond,
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if_block,
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else_block.as_ref().map(|e| &**e),
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None,
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width,
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offset)
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}
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ast::Expr_::ExprIfLet(ref pat, ref cond, ref if_block, ref else_block) => {
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rewrite_if_else(context,
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cond,
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if_block,
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else_block.as_ref().map(|e| &**e),
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Some(pat),
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width,
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offset)
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}
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// We reformat it ourselves because rustc gives us a bad span
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// for ranges, see rust#27162
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ast::Expr_::ExprRange(ref left, ref right) => {
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rewrite_range(context,
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left.as_ref().map(|e| &**e),
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right.as_ref().map(|e| &**e),
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width,
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offset)
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}
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ast::Expr_::ExprPath(ref qself, ref path) => {
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rewrite_path(context, qself.as_ref(), path, width, offset)
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}
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_ => context.codemap.span_to_snippet(self.span).ok()
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}
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}
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}
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impl Rewrite for ast::Block {
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fn rewrite(&self, context: &RewriteContext, width: usize, offset: usize) -> Option<String> {
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let mut visitor = FmtVisitor::from_codemap(context.codemap, context.config);
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visitor.block_indent = context.block_indent;
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let prefix = match self.rules {
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ast::BlockCheckMode::PushUnsafeBlock(..) |
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ast::BlockCheckMode::UnsafeBlock(..) => {
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let snippet = try_opt!(context.codemap.span_to_snippet(self.span).ok());
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let open_pos = try_opt!(snippet.find_uncommented("{"));
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visitor.last_pos = self.span.lo + BytePos(open_pos as u32);
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// Extract comment between unsafe and block start.
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let trimmed = &snippet[6..open_pos].trim();
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if trimmed.len() > 0 {
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// 9 = "unsafe {".len(), 7 = "unsafe ".len()
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format!("unsafe {} ", rewrite_comment(trimmed, true, width - 9, offset + 7))
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} else {
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"unsafe ".to_owned()
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}
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}
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ast::BlockCheckMode::PopUnsafeBlock(..) |
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ast::BlockCheckMode::DefaultBlock => {
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visitor.last_pos = self.span.lo;
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String::new()
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}
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};
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visitor.visit_block(self);
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// Push text between last block item and end of block
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let snippet = visitor.snippet(mk_sp(visitor.last_pos, self.span.hi));
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visitor.buffer.push_str(&snippet);
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Some(format!("{}{}", prefix, visitor.buffer))
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}
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}
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// TODO(#18): implement pattern formatting
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impl Rewrite for ast::Pat {
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fn rewrite(&self, context: &RewriteContext, _: usize, _: usize) -> Option<String> {
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context.codemap.span_to_snippet(self.span).ok()
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}
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}
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// Abstraction over for, while and loop expressions
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struct Loop<'a> {
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cond: Option<&'a ast::Expr>,
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block: &'a ast::Block,
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label: Option<ast::Ident>,
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pat: Option<&'a ast::Pat>,
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keyword: &'a str,
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matcher: &'a str,
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connector: &'a str,
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}
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impl<'a> Loop<'a> {
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fn new_loop(block: &'a ast::Block, label: Option<ast::Ident>) -> Loop<'a> {
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Loop {
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cond: None,
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block: block,
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label: label,
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pat: None,
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keyword: "loop",
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matcher: "",
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connector: "",
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}
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}
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fn new_while(pat: Option<&'a ast::Pat>,
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cond: &'a ast::Expr,
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block: &'a ast::Block,
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label: Option<ast::Ident>)
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-> Loop<'a> {
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Loop {
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cond: Some(cond),
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block: block,
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label: label,
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pat: pat,
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keyword: "while ",
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matcher: match pat {
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Some(..) => "let ",
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None => ""
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},
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connector: " =",
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}
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}
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fn new_for(pat: &'a ast::Pat,
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cond: &'a ast::Expr,
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block: &'a ast::Block,
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label: Option<ast::Ident>)
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-> Loop<'a> {
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Loop {
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cond: Some(cond),
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block: block,
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label: label,
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pat: Some(pat),
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keyword: "for ",
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matcher: "",
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connector: " in",
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}
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}
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}
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impl<'a> Rewrite for Loop<'a> {
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fn rewrite(&self, context: &RewriteContext, width: usize, offset: usize) -> Option<String> {
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let label_string = rewrite_label(self.label);
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// 2 = " {".len()
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let inner_width = width - self.keyword.len() - 2 - label_string.len();
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let inner_offset = offset + self.keyword.len() + label_string.len();
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let pat_expr_string = match self.cond {
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Some(cond) => try_opt!(rewrite_pat_expr(context,
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self.pat,
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cond,
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self.matcher,
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self.connector,
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inner_width,
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inner_offset)),
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None => String::new()
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};
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// FIXME: this drops any comment between "loop" and the block.
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self.block.rewrite(context, width, offset).map(|result| {
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format!("{}{}{} {}", label_string, self.keyword, pat_expr_string, result)
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})
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}
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}
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fn rewrite_label(label: Option<ast::Ident>) -> String {
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match label {
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Some(ident) => format!("{}: ", ident),
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None => "".to_owned()
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}
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}
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// FIXME: this doesn't play well with line breaks
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fn rewrite_range(context: &RewriteContext,
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left: Option<&ast::Expr>,
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right: Option<&ast::Expr>,
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width: usize,
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offset: usize)
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-> Option<String> {
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let left_string = match left {
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// 2 = ..
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Some(expr) => try_opt!(expr.rewrite(context, width - 2, offset)),
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None => String::new()
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};
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let right_string = match right {
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Some(expr) => {
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// 2 = ..
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let max_width = (width - 2).checked_sub(left_string.len()).unwrap_or(0);
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try_opt!(expr.rewrite(context, max_width, offset + 2 + left_string.len()))
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}
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None => String::new()
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};
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Some(format!("{}..{}", left_string, right_string))
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}
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// Rewrites if-else blocks. If let Some(_) = pat, the expression is
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// treated as an if-let-else expression.
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fn rewrite_if_else(context: &RewriteContext,
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cond: &ast::Expr,
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if_block: &ast::Block,
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else_block: Option<&ast::Expr>,
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pat: Option<&ast::Pat>,
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width: usize,
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offset: usize)
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-> Option<String> {
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// 3 = "if ", 2 = " {"
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let pat_expr_string = try_opt!(rewrite_pat_expr(context,
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pat,
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cond,
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"let ",
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" =",
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width - 3 - 2,
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offset + 3));
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let if_block_string = try_opt!(if_block.rewrite(context, width, offset));
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let mut result = format!("if {} {}", pat_expr_string, if_block_string);
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if let Some(else_block) = else_block {
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let else_block_string = try_opt!(else_block.rewrite(context, width, offset));
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result.push_str(" else ");
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result.push_str(&else_block_string);
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}
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Some(result)
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}
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fn rewrite_pat_expr(context: &RewriteContext,
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pat: Option<&ast::Pat>,
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expr: &ast::Expr,
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matcher: &str,
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connector: &str,
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width: usize,
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offset: usize)
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-> Option<String> {
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let pat_offset = offset + matcher.len();
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let mut result = match pat {
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Some(pat) => {
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let pat_string = try_opt!(pat.rewrite(context,
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width - connector.len() - matcher.len(),
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pat_offset));
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format!("{}{}{}", matcher, pat_string, connector)
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}
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None => String::new()
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};
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// Consider only the last line of the pat string.
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let extra_offset = extra_offset(&result, offset);
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// The expression may (partionally) fit on the current line.
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if width > extra_offset + 1 {
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let mut corrected_offset = extra_offset;
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if pat.is_some() {
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result.push(' ');
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corrected_offset += 1;
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}
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let expr_rewrite = expr.rewrite(context,
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width - corrected_offset,
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offset + corrected_offset);
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if let Some(expr_string) = expr_rewrite {
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result.push_str(&expr_string);
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return Some(result);
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}
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}
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// The expression won't fit on the current line, jump to next.
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result.push('\n');
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result.push_str(&make_indent(pat_offset));
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let expr_rewrite = expr.rewrite(context, context.config.max_width - pat_offset, pat_offset);
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result.push_str(&&try_opt!(expr_rewrite));
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Some(result)
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}
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fn rewrite_string_lit(context: &RewriteContext,
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s: &str,
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span: Span,
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width: usize,
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offset: usize)
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-> Option<String> {
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// Check if there is anything to fix: we always try to fixup multi-line
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// strings, or if the string is too long for the line.
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let l_loc = context.codemap.lookup_char_pos(span.lo);
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let r_loc = context.codemap.lookup_char_pos(span.hi);
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if l_loc.line == r_loc.line && r_loc.col.to_usize() <= context.config.max_width {
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return context.codemap.span_to_snippet(span).ok();
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}
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let fmt = StringFormat {
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opener: "\"",
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closer: "\"",
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line_start: " ",
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line_end: "\\",
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width: width,
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offset: offset,
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trim_end: false,
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};
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Some(rewrite_string(&s.escape_default(), &fmt))
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}
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fn rewrite_call(context: &RewriteContext,
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callee: &ast::Expr,
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args: &[ptr::P<ast::Expr>],
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span: Span,
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width: usize,
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offset: usize)
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-> Option<String> {
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debug!("rewrite_call, width: {}, offset: {}", width, offset);
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// TODO using byte lens instead of char lens (and probably all over the place too)
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// 2 is for parens
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let max_callee_width = try_opt!(width.checked_sub(2));
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let callee_str = try_opt!(callee.rewrite(context, max_callee_width, offset));
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debug!("rewrite_call, callee_str: `{}`", callee_str);
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if args.len() == 0 {
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return Some(format!("{}()", callee_str));
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}
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let extra_offset = extra_offset(&callee_str, offset);
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// 2 is for parens.
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let remaining_width = try_opt!(width.checked_sub(extra_offset + 2));
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let offset = offset + extra_offset + 1;
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let block_indent = expr_block_indent(context, offset);
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let inner_context = &RewriteContext { block_indent: block_indent, ..*context };
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let items = itemize_list(context.codemap,
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args.iter(),
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")",
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|item| item.span.lo,
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|item| item.span.hi,
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// Take old span when rewrite fails.
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|item| item.rewrite(inner_context, remaining_width, offset)
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.unwrap_or(context.codemap.span_to_snippet(item.span)
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.unwrap()),
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callee.span.hi + BytePos(1),
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span.hi);
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let fmt = ListFormatting {
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tactic: ListTactic::HorizontalVertical,
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separator: ",",
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trailing_separator: SeparatorTactic::Never,
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indent: offset,
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h_width: remaining_width,
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v_width: remaining_width,
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ends_with_newline: false,
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};
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Some(format!("{}({})", callee_str, write_list(&items.collect::<Vec<_>>(), &fmt)))
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}
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fn expr_block_indent(context: &RewriteContext, offset: usize) -> usize {
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match context.config.expr_indent_style {
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BlockIndentStyle::Inherit => context.block_indent,
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BlockIndentStyle::Tabbed => context.block_indent + context.config.tab_spaces,
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BlockIndentStyle::Visual => offset,
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}
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}
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fn rewrite_paren(context: &RewriteContext,
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subexpr: &ast::Expr,
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width: usize,
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offset: usize)
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-> Option<String> {
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debug!("rewrite_paren, width: {}, offset: {}", width, offset);
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// 1 is for opening paren, 2 is for opening+closing, we want to keep the closing
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// paren on the same line as the subexpr
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let subexpr_str = subexpr.rewrite(context, width-2, offset+1);
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debug!("rewrite_paren, subexpr_str: `{:?}`", subexpr_str);
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subexpr_str.map(|s| format!("({})", s))
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}
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fn rewrite_struct_lit<'a>(context: &RewriteContext,
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path: &ast::Path,
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fields: &'a [ast::Field],
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base: Option<&'a ast::Expr>,
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span: Span,
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width: usize,
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offset: usize)
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-> Option<String> {
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debug!("rewrite_struct_lit: width {}, offset {}", width, offset);
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assert!(fields.len() > 0 || base.is_some());
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enum StructLitField<'a> {
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Regular(&'a ast::Field),
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Base(&'a ast::Expr),
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}
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// 2 = " {".len()
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let path_str = try_opt!(path.rewrite(context, width - 2, offset));
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// Foo { a: Foo } - indent is +3, width is -5.
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let h_budget = width.checked_sub(path_str.len() + 5).unwrap_or(0);
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let (indent, v_budget) = match context.config.struct_lit_style {
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StructLitStyle::VisualIndent => {
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(offset + path_str.len() + 3, h_budget)
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}
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StructLitStyle::BlockIndent => {
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// If we are all on one line, then we'll ignore the indent, and we
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// have a smaller budget.
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let indent = context.block_indent + context.config.tab_spaces;
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let v_budget = context.config.max_width.checked_sub(indent).unwrap_or(0);
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(indent, v_budget)
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}
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};
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let field_iter = fields.into_iter().map(StructLitField::Regular)
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.chain(base.into_iter().map(StructLitField::Base));
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let inner_context = &RewriteContext { block_indent: indent, ..*context };
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let items = itemize_list(context.codemap,
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field_iter,
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"}",
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|item| {
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match *item {
|
|
StructLitField::Regular(ref field) => field.span.lo,
|
|
// 2 = ..
|
|
StructLitField::Base(ref expr) => expr.span.lo - BytePos(2)
|
|
}
|
|
},
|
|
|item| {
|
|
match *item {
|
|
StructLitField::Regular(ref field) => field.span.hi,
|
|
StructLitField::Base(ref expr) => expr.span.hi
|
|
}
|
|
},
|
|
|item| {
|
|
match *item {
|
|
StructLitField::Regular(ref field) => {
|
|
rewrite_field(inner_context, &field, h_budget, indent)
|
|
.unwrap_or(context.codemap.span_to_snippet(field.span)
|
|
.unwrap())
|
|
},
|
|
StructLitField::Base(ref expr) => {
|
|
// 2 = ..
|
|
expr.rewrite(inner_context, h_budget - 2, indent + 2)
|
|
.map(|s| format!("..{}", s))
|
|
.unwrap_or(context.codemap.span_to_snippet(expr.span)
|
|
.unwrap())
|
|
}
|
|
}
|
|
},
|
|
span_after(span, "{", context.codemap),
|
|
span.hi);
|
|
|
|
let fmt = ListFormatting {
|
|
tactic: ListTactic::HorizontalVertical,
|
|
separator: ",",
|
|
trailing_separator: if base.is_some() {
|
|
SeparatorTactic::Never
|
|
} else {
|
|
context.config.struct_lit_trailing_comma
|
|
},
|
|
indent: indent,
|
|
h_width: h_budget,
|
|
v_width: v_budget,
|
|
ends_with_newline: false,
|
|
};
|
|
let fields_str = write_list(&items.collect::<Vec<_>>(), &fmt);
|
|
|
|
match context.config.struct_lit_style {
|
|
StructLitStyle::BlockIndent if fields_str.contains('\n') => {
|
|
let inner_indent = make_indent(context.block_indent + context.config.tab_spaces);
|
|
let outer_indent = make_indent(context.block_indent);
|
|
Some(format!("{} {{\n{}{}\n{}}}", path_str, inner_indent, fields_str, outer_indent))
|
|
}
|
|
_ => Some(format!("{} {{ {} }}", path_str, fields_str)),
|
|
}
|
|
|
|
// FIXME if context.config.struct_lit_style == VisualIndent, but we run out
|
|
// of space, we should fall back to BlockIndent.
|
|
}
|
|
|
|
fn rewrite_field(context: &RewriteContext,
|
|
field: &ast::Field,
|
|
width: usize,
|
|
offset: usize)
|
|
-> Option<String> {
|
|
let name = &field.ident.node.to_string();
|
|
let overhead = name.len() + 2;
|
|
let expr = field.expr.rewrite(context, width - overhead, offset + overhead);
|
|
expr.map(|s| format!("{}: {}", name, s))
|
|
}
|
|
|
|
fn rewrite_tuple_lit(context: &RewriteContext,
|
|
items: &[ptr::P<ast::Expr>],
|
|
span: Span,
|
|
width: usize,
|
|
offset: usize)
|
|
-> Option<String> {
|
|
debug!("rewrite_tuple_lit: width: {}, offset: {}", width, offset);
|
|
let indent = offset + 1;
|
|
// In case of length 1, need a trailing comma
|
|
if items.len() == 1 {
|
|
// 3 = "(" + ",)"
|
|
return items[0].rewrite(context, width - 3, indent).map(|s| format!("({},)", s));
|
|
}
|
|
|
|
let items = itemize_list(context.codemap,
|
|
items.iter(),
|
|
")",
|
|
|item| item.span.lo,
|
|
|item| item.span.hi,
|
|
|item| item.rewrite(context,
|
|
context.config.max_width - indent - 1,
|
|
indent)
|
|
.unwrap_or(context.codemap.span_to_snippet(item.span)
|
|
.unwrap()),
|
|
span.lo + BytePos(1), // Remove parens
|
|
span.hi - BytePos(1));
|
|
|
|
let fmt = ListFormatting {
|
|
tactic: ListTactic::HorizontalVertical,
|
|
separator: ",",
|
|
trailing_separator: SeparatorTactic::Never,
|
|
indent: indent,
|
|
h_width: width - 2,
|
|
v_width: width - 2,
|
|
ends_with_newline: false,
|
|
};
|
|
|
|
Some(format!("({})", write_list(&items.collect::<Vec<_>>(), &fmt)))
|
|
}
|
|
|
|
fn rewrite_binary_op(context: &RewriteContext,
|
|
op: &ast::BinOp,
|
|
lhs: &ast::Expr,
|
|
rhs: &ast::Expr,
|
|
width: usize,
|
|
offset: usize)
|
|
-> Option<String> {
|
|
// FIXME: format comments between operands and operator
|
|
|
|
let operator_str = context.codemap.span_to_snippet(op.span).unwrap();
|
|
|
|
// 1 = space between lhs expr and operator
|
|
let mut result =
|
|
try_opt!(lhs.rewrite(context,
|
|
context.config.max_width - offset - 1 - operator_str.len(),
|
|
offset));
|
|
|
|
result.push(' ');
|
|
result.push_str(&operator_str);
|
|
|
|
// 1 = space between operator and rhs
|
|
let used_width = result.len() + 1;
|
|
let remaining_width = match result.rfind('\n') {
|
|
Some(idx) => (offset + width + idx).checked_sub(used_width).unwrap_or(0),
|
|
None => width.checked_sub(used_width).unwrap_or(0)
|
|
};
|
|
|
|
// Get "full width" rhs and see if it fits on the current line. This
|
|
// usually works fairly well since it tends to place operands of
|
|
// operations with high precendence close together.
|
|
let rhs_result = try_opt!(rhs.rewrite(context, width, offset));
|
|
|
|
// Second condition is needed in case of line break not caused by a
|
|
// shortage of space, but by end-of-line comments, for example.
|
|
if rhs_result.len() > remaining_width || rhs_result.contains('\n') {
|
|
result.push('\n');
|
|
result.push_str(&make_indent(offset));
|
|
} else {
|
|
result.push(' ');
|
|
};
|
|
|
|
result.push_str(&rhs_result);
|
|
Some(result)
|
|
}
|
|
|
|
fn rewrite_unary_op(context: &RewriteContext,
|
|
op: &ast::UnOp,
|
|
expr: &ast::Expr,
|
|
width: usize,
|
|
offset: usize)
|
|
-> Option<String> {
|
|
// For some reason, an UnOp is not spanned like BinOp!
|
|
let operator_str = match *op {
|
|
ast::UnOp::UnUniq => "box ",
|
|
ast::UnOp::UnDeref => "*",
|
|
ast::UnOp::UnNot => "!",
|
|
ast::UnOp::UnNeg => "-"
|
|
};
|
|
|
|
let subexpr = try_opt!(expr.rewrite(context, width - operator_str.len(), offset));
|
|
|
|
Some(format!("{}{}", operator_str, subexpr))
|
|
}
|