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std: Enforce Unicode in fmt::Writer

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This commit is an implementation of [RFC 526][rfc] which is a change to alter
the definition of the old `fmt::FormatWriter`. The new trait, renamed to
`Writer`, now only exposes one method `write_str` in order to guarantee that all
implementations of the formatting traits can only produce valid Unicode.

[rfc]: https://github.com/rust-lang/rfcs/blob/master/text/0526-fmt-text-writer.md

One of the primary improvements of this patch is the performance of the
`.to_string()` method by avoiding an almost-always redundant UTF-8 check. This
is a breaking change due to the renaming of the trait as well as the loss of the
`write` method, but migration paths should be relatively easy:

* All usage of `write` should move to `write_str`. If truly binary data was
  being written in an implementation of `Show`, then it will need to use a
  different trait or an altogether different code path.

* All usage of `write!` should continue to work as-is with no modifications.

* All usage of `Show` where implementations just delegate to another should
  continue to work as-is.

[breaking-change]

Closes #20352
This commit is contained in:
Alex Crichton
2014-12-12 10:59:41 -08:00
parent cd614164e6
commit e423fcf0e0
25 changed files with 320 additions and 359 deletions
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58
src/librustdoc/html/format.rs
View File

@@ -69,7 +69,7 @@ impl<'a> fmt::Show for TyParamBounds<'a> {
let &TyParamBounds(bounds) = self;
for (i, bound) in bounds.iter().enumerate() {
if i > 0 {
try!(f.write(" + ".as_bytes()));
try!(f.write_str(" + "));
}
try!(write!(f, "{}", *bound));
}
@@ -80,24 +80,24 @@ impl<'a> fmt::Show for TyParamBounds<'a> {
impl fmt::Show for clean::Generics {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
if self.lifetimes.len() == 0 && self.type_params.len() == 0 { return Ok(()) }
try!(f.write("&lt;".as_bytes()));
try!(f.write_str("&lt;"));
for (i, life) in self.lifetimes.iter().enumerate() {
if i > 0 {
try!(f.write(", ".as_bytes()));
try!(f.write_str(", "));
}
try!(write!(f, "{}", *life));
}
if self.type_params.len() > 0 {
if self.lifetimes.len() > 0 {
try!(f.write(", ".as_bytes()));
try!(f.write_str(", "));
}
for (i, tp) in self.type_params.iter().enumerate() {
if i > 0 {
try!(f.write(", ".as_bytes()))
try!(f.write_str(", "))
}
try!(f.write(tp.name.as_bytes()));
try!(f.write_str(tp.name[]));
if tp.bounds.len() > 0 {
try!(write!(f, ": {}", TyParamBounds(tp.bounds.as_slice())));
@@ -109,7 +109,7 @@ impl fmt::Show for clean::Generics {
};
}
}
try!(f.write("&gt;".as_bytes()));
try!(f.write_str("&gt;"));
Ok(())
}
}
@@ -120,10 +120,10 @@ impl<'a> fmt::Show for WhereClause<'a> {
if gens.where_predicates.len() == 0 {
return Ok(());
}
try!(f.write(" <span class='where'>where ".as_bytes()));
try!(f.write_str(" <span class='where'>where "));
for (i, pred) in gens.where_predicates.iter().enumerate() {
if i > 0 {
try!(f.write(", ".as_bytes()));
try!(f.write_str(", "));
}
match pred {
&clean::WherePredicate::BoundPredicate { ref ty, ref bounds } => {
@@ -135,7 +135,7 @@ impl<'a> fmt::Show for WhereClause<'a> {
try!(write!(f, "{}: ", lifetime));
for (i, lifetime) in bounds.iter().enumerate() {
if i > 0 {
try!(f.write(" + ".as_bytes()));
try!(f.write_str(" + "));
}
try!(write!(f, "{}", lifetime));
@@ -146,14 +146,14 @@ impl<'a> fmt::Show for WhereClause<'a> {
}
}
}
try!(f.write("</span>".as_bytes()));
try!(f.write_str("</span>"));
Ok(())
}
}
impl fmt::Show for clean::Lifetime {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
try!(f.write(self.get_ref().as_bytes()));
try!(f.write_str(self.get_ref()));
Ok(())
}
}
@@ -161,14 +161,14 @@ impl fmt::Show for clean::Lifetime {
impl fmt::Show for clean::PolyTrait {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
if self.lifetimes.len() > 0 {
try!(f.write("for&lt;".as_bytes()));
try!(f.write_str("for&lt;"));
for (i, lt) in self.lifetimes.iter().enumerate() {
if i > 0 {
try!(f.write(", ".as_bytes()));
try!(f.write_str(", "));
}
try!(write!(f, "{}", lt));
}
try!(f.write("&gt; ".as_bytes()));
try!(f.write_str("&gt; "));
}
write!(f, "{}", self.trait_)
}
@@ -196,38 +196,38 @@ impl fmt::Show for clean::PathParameters {
match *self {
clean::PathParameters::AngleBracketed { ref lifetimes, ref types } => {
if lifetimes.len() > 0 || types.len() > 0 {
try!(f.write("&lt;".as_bytes()));
try!(f.write_str("&lt;"));
let mut comma = false;
for lifetime in lifetimes.iter() {
if comma {
try!(f.write(", ".as_bytes()));
try!(f.write_str(", "));
}
comma = true;
try!(write!(f, "{}", *lifetime));
}
for ty in types.iter() {
if comma {
try!(f.write(", ".as_bytes()));
try!(f.write_str(", "));
}
comma = true;
try!(write!(f, "{}", *ty));
}
try!(f.write("&gt;".as_bytes()));
try!(f.write_str("&gt;"));
}
}
clean::PathParameters::Parenthesized { ref inputs, ref output } => {
try!(f.write("(".as_bytes()));
try!(f.write_str("("));
let mut comma = false;
for ty in inputs.iter() {
if comma {
try!(f.write(", ".as_bytes()));
try!(f.write_str(", "));
}
comma = true;
try!(write!(f, "{}", *ty));
}
try!(f.write(")".as_bytes()));
try!(f.write_str(")"));
if let Some(ref ty) = *output {
try!(f.write(" -&gt; ".as_bytes()));
try!(f.write_str(" -&gt; "));
try!(write!(f, "{}", ty));
}
}
@@ -238,7 +238,7 @@ impl fmt::Show for clean::PathParameters {
impl fmt::Show for clean::PathSegment {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
try!(f.write(self.name.as_bytes()));
try!(f.write_str(self.name.as_slice()));
write!(f, "{}", self.params)
}
}
@@ -246,12 +246,12 @@ impl fmt::Show for clean::PathSegment {
impl fmt::Show for clean::Path {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
if self.global {
try!(f.write("::".as_bytes()))
try!(f.write_str("::"))
}
for (i, seg) in self.segments.iter().enumerate() {
if i > 0 {
try!(f.write("::".as_bytes()))
try!(f.write_str("::"))
}
try!(write!(f, "{}", seg));
}
@@ -433,10 +433,10 @@ impl fmt::Show for clean::Type {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
match *self {
clean::TyParamBinder(id) => {
f.write(cache().typarams[ast_util::local_def(id)].as_bytes())
f.write_str(cache().typarams[ast_util::local_def(id)][])
}
clean::Generic(ref name) => {
f.write(name.as_bytes())
f.write_str(name.as_slice())
}
clean::ResolvedPath{ did, ref typarams, ref path } => {
try!(resolved_path(f, did, path, false));
@@ -522,7 +522,7 @@ impl fmt::Show for clean::Type {
primitive_link(f, clean::Slice,
format!("[{}, ..{}]", **t, *s).as_slice())
}
clean::Bottom => f.write("!".as_bytes()),
clean::Bottom => f.write_str("!"),
clean::RawPointer(m, ref t) => {
write!(f, "*{}{}", RawMutableSpace(m), **t)
}