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make value internal visitor support borrowing
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@KodrAus
KodrAus committed Jan 31, 2020
1 parent ddb118e commit 6743f4a
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Showing 4 changed files with 216 additions and 96 deletions.
123 changes: 91 additions & 32 deletions src/kv/value/internal.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -24,17 +24,9 @@ pub(super) enum Inner<'v> {
}

impl<'v> Inner<'v> {
pub(super) fn visit(&self, visitor: &mut dyn Visitor) -> Result<(), Error> {
match *self {
Inner::Primitive(value) => match value {
Primitive::Signed(value) => visitor.i64(value),
Primitive::Unsigned(value) => visitor.u64(value),
Primitive::Float(value) => visitor.f64(value),
Primitive::Bool(value) => visitor.bool(value),
Primitive::Char(value) => visitor.char(value),
Primitive::Str(value) => visitor.str(value),
Primitive::None => visitor.none(),
},
pub(super) fn visit(self, visitor: &mut dyn Visitor<'v>) -> Result<(), Error> {
match self {
Inner::Primitive(value) => value.visit(visitor),
Inner::Fill(value) => value.fill(&mut Slot::new(visitor)),
Inner::Debug(value) => visitor.debug(value),
Inner::Display(value) => visitor.display(value),
Expand All @@ -46,7 +38,7 @@ impl<'v> Inner<'v> {
}

/// The internal serialization contract.
pub(super) trait Visitor {
pub(super) trait Visitor<'v> {
fn debug(&mut self, v: &dyn fmt::Debug) -> Result<(), Error>;
fn display(&mut self, v: &dyn fmt::Display) -> Result<(), Error> {
self.debug(&format_args!("{}", v))
Expand All @@ -57,7 +49,12 @@ pub(super) trait Visitor {
fn f64(&mut self, v: f64) -> Result<(), Error>;
fn bool(&mut self, v: bool) -> Result<(), Error>;
fn char(&mut self, v: char) -> Result<(), Error>;

fn str(&mut self, v: &str) -> Result<(), Error>;
fn borrowed_str(&mut self, v: &'v str) -> Result<(), Error> {
self.str(v)
}

fn none(&mut self) -> Result<(), Error>;

#[cfg(feature = "kv_unstable_sval")]
Expand All @@ -75,35 +72,45 @@ pub(super) enum Primitive<'v> {
None,
}

impl<'v> Primitive<'v> {
fn visit(self, visitor: &mut dyn Visitor<'v>) -> Result<(), Error> {
match self {
Primitive::Signed(value) => visitor.i64(value),
Primitive::Unsigned(value) => visitor.u64(value),
Primitive::Float(value) => visitor.f64(value),
Primitive::Bool(value) => visitor.bool(value),
Primitive::Char(value) => visitor.char(value),
Primitive::Str(value) => visitor.borrowed_str(value),
Primitive::None => visitor.none(),
}
}
}

mod coerce {
use super::*;

impl<'v> Inner<'v> {
pub(in crate::kv::value) fn as_str(&self) -> Option<&str> {
if let Inner::Primitive(Primitive::Str(value)) = self {
Some(value)
} else {
self.coerce().into_primitive().into_str()
}
pub(in crate::kv::value) fn get_str(&self) -> Option<&str> {
self.coerce().into_primitive().into_str()
}

pub(in crate::kv::value) fn as_u64(&self) -> Option<u64> {
pub(in crate::kv::value) fn get_u64(&self) -> Option<u64> {
self.coerce().into_primitive().into_u64()
}

pub(in crate::kv::value) fn as_i64(&self) -> Option<i64> {
pub(in crate::kv::value) fn get_i64(&self) -> Option<i64> {
self.coerce().into_primitive().into_i64()
}

pub(in crate::kv::value) fn as_f64(&self) -> Option<f64> {
pub(in crate::kv::value) fn get_f64(&self) -> Option<f64> {
self.coerce().into_primitive().into_f64()
}

pub(in crate::kv::value) fn as_char(&self) -> Option<char> {
pub(in crate::kv::value) fn get_char(&self) -> Option<char> {
self.coerce().into_primitive().into_char()
}

pub(in crate::kv::value) fn as_bool(&self) -> Option<bool> {
pub(in crate::kv::value) fn get_bool(&self) -> Option<bool> {
self.coerce().into_primitive().into_bool()
}

Expand All @@ -116,7 +123,7 @@ mod coerce {
}
}

impl<'v> Visitor for Coerce<'v> {
impl<'v> Visitor<'v> for Coerce<'v> {
fn debug(&mut self, _: &dyn fmt::Debug) -> Result<(), Error> {
Ok(())
}
Expand Down Expand Up @@ -146,8 +153,13 @@ mod coerce {
Ok(())
}

fn borrowed_str(&mut self, v: &'v str) -> Result<(), Error> {
self.0 = Coerced::Primitive(Primitive::Str(v));
Ok(())
}

#[cfg(not(feature = "std"))]
fn str(&mut self, v: &str) -> Result<(), Error> {
fn str(&mut self, _: &str) -> Result<(), Error> {
Ok(())
}

Expand Down Expand Up @@ -185,6 +197,7 @@ mod coerce {
fn into_primitive(self) -> Primitive<'v> {
match self {
Coerced::Primitive(value) => value,
#[cfg(feature = "std")]
_ => Primitive::None,
}
}
Expand Down Expand Up @@ -247,7 +260,7 @@ mod coerce {
use std::borrow::Cow;

impl<'v> Inner<'v> {
pub(in crate::kv::value) fn to_str(&self) -> Option<Cow<str>> {
pub(in crate::kv::value) fn get_string(&self) -> Option<Cow<str>> {
self.coerce().into_string()
}
}
Expand Down Expand Up @@ -289,6 +302,36 @@ mod fmt_support {
}
}

impl<'s, 'f> Slot<'s, 'f> {
/// Fill the slot with a debuggable value.
///
/// The given value doesn't need to satisfy any particular lifetime constraints.
///
/// # Panics
///
/// Calling more than a single `fill` method on this slot will panic.
pub fn fill_debug<T>(&mut self, value: T) -> Result<(), Error>
where
T: fmt::Debug,
{
self.fill(|visitor| visitor.debug(&value))
}

/// Fill the slot with a displayable value.
///
/// The given value doesn't need to satisfy any particular lifetime constraints.
///
/// # Panics
///
/// Calling more than a single `fill` method on this slot will panic.
pub fn fill_display<T>(&mut self, value: T) -> Result<(), Error>
where
T: fmt::Display,
{
self.fill(|visitor| visitor.display(&value))
}
}

impl<'v> fmt::Debug for kv::Value<'v> {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
self.visit(&mut FmtVisitor(f))?;
Expand All @@ -307,7 +350,7 @@ mod fmt_support {

struct FmtVisitor<'a, 'b: 'a>(&'a mut fmt::Formatter<'b>);

impl<'a, 'b: 'a> Visitor for FmtVisitor<'a, 'b> {
impl<'a, 'b: 'a, 'v> Visitor<'v> for FmtVisitor<'a, 'b> {
fn debug(&mut self, v: &dyn fmt::Debug) -> Result<(), Error> {
v.fmt(self.0)?;

Expand Down Expand Up @@ -368,6 +411,22 @@ pub(super) mod sval_support {
}
}

impl<'s, 'f> Slot<'s, 'f> {
/// Fill the slot with a structured value.
///
/// The given value doesn't need to satisfy any particular lifetime constraints.
///
/// # Panics
///
/// Calling more than a single `fill` method on this slot will panic.
pub fn fill_sval<T>(&mut self, value: T) -> Result<(), Error>
where
T: sval::Value,
{
self.fill(|visitor| visitor.sval(&value))
}
}

impl<'v> sval::Value for kv::Value<'v> {
fn stream(&self, s: &mut sval::value::Stream) -> sval::value::Result {
self.visit(&mut SvalVisitor(s)).map_err(Error::into_sval)?;
Expand Down Expand Up @@ -395,7 +454,7 @@ pub(super) mod sval_support {

struct SvalVisitor<'a, 'b: 'a>(&'a mut sval::value::Stream<'b>);

impl<'a, 'b: 'a> Visitor for SvalVisitor<'a, 'b> {
impl<'a, 'b: 'a, 'v> Visitor<'v> for SvalVisitor<'a, 'b> {
fn debug(&mut self, v: &dyn fmt::Debug) -> Result<(), Error> {
self.0
.fmt(format_args!("{:?}", v))
Expand Down Expand Up @@ -496,21 +555,21 @@ pub(super) mod sval_support {
}

#[test]
fn coersion() {
fn sval_coersion() {
assert_eq!(
42u64,
kv::Value::from_sval(&42u64)
.as_u64()
.get_u64()
.expect("invalid value")
);

assert!(kv::Value::from_sval(&"a string").as_str().is_none());
assert!(kv::Value::from_sval(&"a string").get_str().is_none());

#[cfg(feature = "std")]
assert_eq!(
"a string",
&*kv::Value::from_sval(&"a string")
.to_str()
.get_string()
.expect("invalid value")
);
}
Expand Down
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