rust/src/libcore/fmt/builders.rs
2018-05-07 10:26:28 -07:00

540 lines
15 KiB
Rust

// Copyright 2015 The Rust Project Developers. See the COPYRIGHT
// file at the top-level directory of this distribution and at
// http://rust-lang.org/COPYRIGHT.
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.
use fmt;
struct PadAdapter<'a> {
buf: &'a mut (fmt::Write + 'a),
on_newline: bool,
}
impl<'a> PadAdapter<'a> {
fn wrap<'b, 'c: 'a+'b>(fmt: &'c mut fmt::Formatter, slot: &'b mut Option<Self>)
-> fmt::Formatter<'b> {
fmt.wrap_buf(move |buf| {
*slot = Some(PadAdapter {
buf,
on_newline: false,
});
slot.as_mut().unwrap()
})
}
}
impl<'a> fmt::Write for PadAdapter<'a> {
fn write_str(&mut self, mut s: &str) -> fmt::Result {
while !s.is_empty() {
if self.on_newline {
self.buf.write_str(" ")?;
}
let split = match s.find('\n') {
Some(pos) => {
self.on_newline = true;
pos + 1
}
None => {
self.on_newline = false;
s.len()
}
};
self.buf.write_str(&s[..split])?;
s = &s[split..];
}
Ok(())
}
}
/// A struct to help with [`fmt::Debug`](trait.Debug.html) implementations.
///
/// This is useful when you wish to output a formatted struct as a part of your
/// [`Debug::fmt`](trait.Debug.html#tymethod.fmt) implementation.
///
/// This can be constructed by the
/// [`Formatter::debug_struct`](struct.Formatter.html#method.debug_struct)
/// method.
///
/// # Examples
///
/// ```
/// use std::fmt;
///
/// struct Foo {
/// bar: i32,
/// baz: String,
/// }
///
/// impl fmt::Debug for Foo {
/// fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
/// fmt.debug_struct("Foo")
/// .field("bar", &self.bar)
/// .field("baz", &self.baz)
/// .finish()
/// }
/// }
///
/// // prints "Foo { bar: 10, baz: "Hello World" }"
/// println!("{:?}", Foo { bar: 10, baz: "Hello World".to_string() });
/// ```
#[must_use = "must eventually call `finish()` on Debug builders"]
#[allow(missing_debug_implementations)]
#[stable(feature = "debug_builders", since = "1.2.0")]
pub struct DebugStruct<'a, 'b: 'a> {
fmt: &'a mut fmt::Formatter<'b>,
result: fmt::Result,
has_fields: bool,
}
pub fn debug_struct_new<'a, 'b>(fmt: &'a mut fmt::Formatter<'b>,
name: &str)
-> DebugStruct<'a, 'b> {
let result = fmt.write_str(name);
DebugStruct {
fmt,
result,
has_fields: false,
}
}
impl<'a, 'b: 'a> DebugStruct<'a, 'b> {
/// Adds a new field to the generated struct output.
#[stable(feature = "debug_builders", since = "1.2.0")]
pub fn field(&mut self, name: &str, value: &fmt::Debug) -> &mut DebugStruct<'a, 'b> {
self.result = self.result.and_then(|_| {
let prefix = if self.has_fields {
","
} else {
" {"
};
if self.is_pretty() {
let mut slot = None;
let mut writer = PadAdapter::wrap(&mut self.fmt, &mut slot);
writer.write_str(prefix)?;
writer.write_str("\n")?;
writer.write_str(name)?;
writer.write_str(": ")?;
value.fmt(&mut writer)
} else {
write!(self.fmt, "{} {}: ", prefix, name)?;
value.fmt(self.fmt)
}
});
self.has_fields = true;
self
}
/// Finishes output and returns any error encountered.
#[stable(feature = "debug_builders", since = "1.2.0")]
pub fn finish(&mut self) -> fmt::Result {
if self.has_fields {
self.result = self.result.and_then(|_| {
if self.is_pretty() {
self.fmt.write_str("\n}")
} else {
self.fmt.write_str(" }")
}
});
}
self.result
}
fn is_pretty(&self) -> bool {
self.fmt.alternate()
}
}
/// A struct to help with [`fmt::Debug`](trait.Debug.html) implementations.
///
/// This is useful when you wish to output a formatted tuple as a part of your
/// [`Debug::fmt`](trait.Debug.html#tymethod.fmt) implementation.
///
/// This can be constructed by the
/// [`Formatter::debug_tuple`](struct.Formatter.html#method.debug_tuple)
/// method.
///
/// # Examples
///
/// ```
/// use std::fmt;
///
/// struct Foo(i32, String);
///
/// impl fmt::Debug for Foo {
/// fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
/// fmt.debug_tuple("Foo")
/// .field(&self.0)
/// .field(&self.1)
/// .finish()
/// }
/// }
///
/// // prints "Foo(10, "Hello World")"
/// println!("{:?}", Foo(10, "Hello World".to_string()));
/// ```
#[must_use = "must eventually call `finish()` on Debug builders"]
#[allow(missing_debug_implementations)]
#[stable(feature = "debug_builders", since = "1.2.0")]
pub struct DebugTuple<'a, 'b: 'a> {
fmt: &'a mut fmt::Formatter<'b>,
result: fmt::Result,
fields: usize,
empty_name: bool,
}
pub fn debug_tuple_new<'a, 'b>(fmt: &'a mut fmt::Formatter<'b>, name: &str) -> DebugTuple<'a, 'b> {
let result = fmt.write_str(name);
DebugTuple {
fmt,
result,
fields: 0,
empty_name: name.is_empty(),
}
}
impl<'a, 'b: 'a> DebugTuple<'a, 'b> {
/// Adds a new field to the generated tuple struct output.
#[stable(feature = "debug_builders", since = "1.2.0")]
pub fn field(&mut self, value: &fmt::Debug) -> &mut DebugTuple<'a, 'b> {
self.result = self.result.and_then(|_| {
let (prefix, space) = if self.fields > 0 {
(",", " ")
} else {
("(", "")
};
if self.is_pretty() {
let mut slot = None;
let mut writer = PadAdapter::wrap(&mut self.fmt, &mut slot);
writer.write_str(prefix)?;
writer.write_str("\n")?;
value.fmt(&mut writer)
} else {
self.fmt.write_str(prefix)?;
self.fmt.write_str(space)?;
value.fmt(self.fmt)
}
});
self.fields += 1;
self
}
/// Finishes output and returns any error encountered.
#[stable(feature = "debug_builders", since = "1.2.0")]
pub fn finish(&mut self) -> fmt::Result {
if self.fields > 0 {
self.result = self.result.and_then(|_| {
if self.is_pretty() {
self.fmt.write_str("\n")?;
}
if self.fields == 1 && self.empty_name {
self.fmt.write_str(",")?;
}
self.fmt.write_str(")")
});
}
self.result
}
fn is_pretty(&self) -> bool {
self.fmt.alternate()
}
}
struct DebugInner<'a, 'b: 'a> {
fmt: &'a mut fmt::Formatter<'b>,
result: fmt::Result,
has_fields: bool,
}
impl<'a, 'b: 'a> DebugInner<'a, 'b> {
fn entry(&mut self, entry: &fmt::Debug) {
self.result = self.result.and_then(|_| {
if self.is_pretty() {
let mut slot = None;
let mut writer = PadAdapter::wrap(&mut self.fmt, &mut slot);
writer.write_str(if self.has_fields {
",\n"
} else {
"\n"
})?;
entry.fmt(&mut writer)
} else {
if self.has_fields {
self.fmt.write_str(", ")?
}
entry.fmt(self.fmt)
}
});
self.has_fields = true;
}
pub fn finish(&mut self) {
let prefix = if self.is_pretty() && self.has_fields {
"\n"
} else {
""
};
self.result = self.result.and_then(|_| self.fmt.write_str(prefix));
}
fn is_pretty(&self) -> bool {
self.fmt.alternate()
}
}
/// A struct to help with [`fmt::Debug`](trait.Debug.html) implementations.
///
/// This is useful when you wish to output a formatted set of items as a part
/// of your [`Debug::fmt`](trait.Debug.html#tymethod.fmt) implementation.
///
/// This can be constructed by the
/// [`Formatter::debug_set`](struct.Formatter.html#method.debug_set)
/// method.
///
/// # Examples
///
/// ```
/// use std::fmt;
///
/// struct Foo(Vec<i32>);
///
/// impl fmt::Debug for Foo {
/// fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
/// fmt.debug_set().entries(self.0.iter()).finish()
/// }
/// }
///
/// // prints "{10, 11}"
/// println!("{:?}", Foo(vec![10, 11]));
/// ```
#[must_use = "must eventually call `finish()` on Debug builders"]
#[allow(missing_debug_implementations)]
#[stable(feature = "debug_builders", since = "1.2.0")]
pub struct DebugSet<'a, 'b: 'a> {
inner: DebugInner<'a, 'b>,
}
pub fn debug_set_new<'a, 'b>(fmt: &'a mut fmt::Formatter<'b>) -> DebugSet<'a, 'b> {
let result = write!(fmt, "{{");
DebugSet {
inner: DebugInner {
fmt,
result,
has_fields: false,
},
}
}
impl<'a, 'b: 'a> DebugSet<'a, 'b> {
/// Adds a new entry to the set output.
#[stable(feature = "debug_builders", since = "1.2.0")]
pub fn entry(&mut self, entry: &fmt::Debug) -> &mut DebugSet<'a, 'b> {
self.inner.entry(entry);
self
}
/// Adds the contents of an iterator of entries to the set output.
#[stable(feature = "debug_builders", since = "1.2.0")]
pub fn entries<D, I>(&mut self, entries: I) -> &mut DebugSet<'a, 'b>
where D: fmt::Debug,
I: IntoIterator<Item = D>
{
for entry in entries {
self.entry(&entry);
}
self
}
/// Finishes output and returns any error encountered.
#[stable(feature = "debug_builders", since = "1.2.0")]
pub fn finish(&mut self) -> fmt::Result {
self.inner.finish();
self.inner.result.and_then(|_| self.inner.fmt.write_str("}"))
}
}
/// A struct to help with [`fmt::Debug`](trait.Debug.html) implementations.
///
/// This is useful when you wish to output a formatted list of items as a part
/// of your [`Debug::fmt`](trait.Debug.html#tymethod.fmt) implementation.
///
/// This can be constructed by the
/// [`Formatter::debug_list`](struct.Formatter.html#method.debug_list)
/// method.
///
/// # Examples
///
/// ```
/// use std::fmt;
///
/// struct Foo(Vec<i32>);
///
/// impl fmt::Debug for Foo {
/// fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
/// fmt.debug_list().entries(self.0.iter()).finish()
/// }
/// }
///
/// // prints "[10, 11]"
/// println!("{:?}", Foo(vec![10, 11]));
/// ```
#[must_use = "must eventually call `finish()` on Debug builders"]
#[allow(missing_debug_implementations)]
#[stable(feature = "debug_builders", since = "1.2.0")]
pub struct DebugList<'a, 'b: 'a> {
inner: DebugInner<'a, 'b>,
}
pub fn debug_list_new<'a, 'b>(fmt: &'a mut fmt::Formatter<'b>) -> DebugList<'a, 'b> {
let result = write!(fmt, "[");
DebugList {
inner: DebugInner {
fmt,
result,
has_fields: false,
},
}
}
impl<'a, 'b: 'a> DebugList<'a, 'b> {
/// Adds a new entry to the list output.
#[stable(feature = "debug_builders", since = "1.2.0")]
pub fn entry(&mut self, entry: &fmt::Debug) -> &mut DebugList<'a, 'b> {
self.inner.entry(entry);
self
}
/// Adds the contents of an iterator of entries to the list output.
#[stable(feature = "debug_builders", since = "1.2.0")]
pub fn entries<D, I>(&mut self, entries: I) -> &mut DebugList<'a, 'b>
where D: fmt::Debug,
I: IntoIterator<Item = D>
{
for entry in entries {
self.entry(&entry);
}
self
}
/// Finishes output and returns any error encountered.
#[stable(feature = "debug_builders", since = "1.2.0")]
pub fn finish(&mut self) -> fmt::Result {
self.inner.finish();
self.inner.result.and_then(|_| self.inner.fmt.write_str("]"))
}
}
/// A struct to help with [`fmt::Debug`](trait.Debug.html) implementations.
///
/// This is useful when you wish to output a formatted map as a part of your
/// [`Debug::fmt`](trait.Debug.html#tymethod.fmt) implementation.
///
/// This can be constructed by the
/// [`Formatter::debug_map`](struct.Formatter.html#method.debug_map)
/// method.
///
/// # Examples
///
/// ```
/// use std::fmt;
///
/// struct Foo(Vec<(String, i32)>);
///
/// impl fmt::Debug for Foo {
/// fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
/// fmt.debug_map().entries(self.0.iter().map(|&(ref k, ref v)| (k, v))).finish()
/// }
/// }
///
/// // prints "{"A": 10, "B": 11}"
/// println!("{:?}", Foo(vec![("A".to_string(), 10), ("B".to_string(), 11)]));
/// ```
#[must_use = "must eventually call `finish()` on Debug builders"]
#[allow(missing_debug_implementations)]
#[stable(feature = "debug_builders", since = "1.2.0")]
pub struct DebugMap<'a, 'b: 'a> {
fmt: &'a mut fmt::Formatter<'b>,
result: fmt::Result,
has_fields: bool,
}
pub fn debug_map_new<'a, 'b>(fmt: &'a mut fmt::Formatter<'b>) -> DebugMap<'a, 'b> {
let result = write!(fmt, "{{");
DebugMap {
fmt,
result,
has_fields: false,
}
}
impl<'a, 'b: 'a> DebugMap<'a, 'b> {
/// Adds a new entry to the map output.
#[stable(feature = "debug_builders", since = "1.2.0")]
pub fn entry(&mut self, key: &fmt::Debug, value: &fmt::Debug) -> &mut DebugMap<'a, 'b> {
self.result = self.result.and_then(|_| {
if self.is_pretty() {
let mut slot = None;
let mut writer = PadAdapter::wrap(&mut self.fmt, &mut slot);
writer.write_str(if self.has_fields {
",\n"
} else {
"\n"
})?;
key.fmt(&mut writer)?;
writer.write_str(": ")?;
value.fmt(&mut writer)
} else {
if self.has_fields {
self.fmt.write_str(", ")?
}
key.fmt(self.fmt)?;
self.fmt.write_str(": ")?;
value.fmt(self.fmt)
}
});
self.has_fields = true;
self
}
/// Adds the contents of an iterator of entries to the map output.
#[stable(feature = "debug_builders", since = "1.2.0")]
pub fn entries<K, V, I>(&mut self, entries: I) -> &mut DebugMap<'a, 'b>
where K: fmt::Debug,
V: fmt::Debug,
I: IntoIterator<Item = (K, V)>
{
for (k, v) in entries {
self.entry(&k, &v);
}
self
}
/// Finishes output and returns any error encountered.
#[stable(feature = "debug_builders", since = "1.2.0")]
pub fn finish(&mut self) -> fmt::Result {
let prefix = if self.is_pretty() && self.has_fields {
"\n"
} else {
""
};
self.result.and_then(|_| write!(self.fmt, "{}}}", prefix))
}
fn is_pretty(&self) -> bool {
self.fmt.alternate()
}
}