Introduce an `alloc` feature

Cargo.toml

@@ -25,7 +25,9 @@ name = "chrono"
 
 [features]
 default = ["clock", "std"]
+alloc = []
 std = []
+serde-1 = ["serde", "alloc"]
 clock = ["time", "std"]
 wasmbind = ["wasm-bindgen", "js-sys"]
 
@@ -34,7 +36,7 @@ time = { version = "0.1.39", optional = true }
 num-integer = { version = "0.1.36", default-features = false }
 num-traits = { version = "0.2", default-features = false }
 rustc-serialize = { version = "0.3.20", optional = true }
-serde = { version = "1.0.99", default-features = false, optional = true }
+serde = { version = "1.0.99", default-features = false, features = ["alloc"], optional = true }
 
 [target.'cfg(all(target_arch = "wasm32", not(target_os = "emscripten")))'.dependencies]
 wasm-bindgen = { version = "0.2", optional = true }

README.md

@@ -52,7 +52,7 @@ feature like this:
 
 ```toml
 [dependencies]
-chrono = { version = "0.4", features = ["serde"] }
+chrono = { version = "0.4", features = ["serde-1"] }
 ```
 
 Then put this in your crate root:

ci/core-test/Cargo.toml

@@ -9,3 +9,6 @@ edition = "2018"
 
 [dependencies]
 chrono = { path = "../..", default-features = false, features = ["serde"] }
+
+[features]
+alloc = ["chrono/alloc"]

ci/travis.sh

@@ -48,20 +48,20 @@ build_and_test_nonwasm() {
   TZ=ACST-9:30 channel test -v --lib
   channel build -v --features rustc-serialize
   TZ=EST4 channel test -v --features rustc-serialize --lib
-  channel build -v --features serde
+  channel build -v --features serde-1
-  TZ=UTC0 channel test -v --features serde --lib
+  TZ=UTC0 channel test -v --features serde-1 --lib
-  channel build -v --features serde,rustc-serialize
+  channel build -v --features serde-1,rustc-serialize
-  TZ=Asia/Katmandu channel test -v --features serde,rustc-serialize
+  TZ=Asia/Katmandu channel test -v --features serde-1,rustc-serialize
 
   # without default "clock" feature
   channel build -v --no-default-features --features std
   TZ=ACST-9:30 channel test -v --no-default-features --lib
   channel build -v --no-default-features --features std,rustc-serialize
   TZ=EST4 channel test -v --no-default-features --features rustc-serialize --lib
-  channel build -v --no-default-features --features std,serde
+  channel build -v --no-default-features --features std,serde-1
-  TZ=UTC0 channel test -v --no-default-features --features serde --lib
+  TZ=UTC0 channel test -v --no-default-features --features serde-1 --lib
-  channel build -v --no-default-features --features std,serde,rustc-serialize
+  channel build -v --no-default-features --features std,serde-1,rustc-serialize
-  TZ=Asia/Katmandu channel test -v --no-default-features --features std,serde,rustc-serialize --lib
+  TZ=Asia/Katmandu channel test -v --no-default-features --features std,serde-1,rustc-serialize --lib
 }
 
 build_and_test_wasm() {
@@ -81,7 +81,7 @@ build_only() {
   cargo clean
   channel build -v
   channel build -v --features rustc-serialize
-  channel build -v --features 'serde bincode'
+  channel build -v --features 'serde-1 bincode'
   channel build -v --no-default-features --features std
 }
 
@@ -99,7 +99,7 @@ run_clippy() {
         exit
     fi
 
-    cargo clippy --features 'serde bincode rustc-serialize' -- -Dclippy
+    cargo clippy --features 'serde-1 bincode rustc-serialize' -- -Dclippy
 }
 
 check_readme() {
@@ -123,9 +123,7 @@ build_and_test
 
 CHANNEL=stable
 build_and_test
+build_core_test
 
 CHANNEL=1.13.0
 build_only
-
-CHANNEL=stable
-build_core_test

src/date.rs

@@ -12,7 +12,8 @@ use {Weekday, Datelike};
 use offset::{TimeZone, Utc};
 use naive::{self, NaiveDate, NaiveTime, IsoWeek};
 use DateTime;
-use format::{Item, DelayedFormat, StrftimeItems};
+#[cfg(any(feature = "alloc", feature = "std", test))]
+use format::{DelayedFormat, Item, StrftimeItems};
 
 /// ISO 8601 calendar date with time zone.
 ///
@@ -255,6 +256,7 @@ fn map_local<Tz: TimeZone, F>(d: &Date<Tz>, mut f: F) -> Option<Date<Tz>>
 
 impl<Tz: TimeZone> Date<Tz> where Tz::Offset: fmt::Display {
     /// Formats the date with the specified formatting items.
+    #[cfg(any(feature = "alloc", feature = "std", test))]
     #[inline]
     pub fn format_with_items<'a, I>(&self, items: I) -> DelayedFormat<I>
             where I: Iterator<Item=Item<'a>> + Clone {
@@ -264,6 +266,7 @@ impl<Tz: TimeZone> Date<Tz> where Tz::Offset: fmt::Display {
     /// Formats the date with the specified format string.
     /// See the [`format::strftime` module](./format/strftime/index.html)
     /// on the supported escape sequences.
+    #[cfg(any(feature = "alloc", feature = "std", test))]
     #[inline]
     pub fn format<'a>(&self, fmt: &'a str) -> DelayedFormat<StrftimeItems<'a>> {
         self.format_with_items(StrftimeItems::new(fmt))

src/datetime.rs

@@ -10,7 +10,7 @@ use core::ops::{Add, Sub};
 use std::time::{SystemTime, UNIX_EPOCH};
 use oldtime::Duration as OldDuration;
 
-#[cfg(not(any(feature = "std", test)))]
+#[cfg(any(feature = "alloc", feature = "std", test))]
 use alloc::string::{String, ToString};
 
 use {Weekday, Timelike, Datelike};
@@ -20,7 +20,9 @@ use offset::{TimeZone, Offset, Utc, FixedOffset};
 use naive::{NaiveTime, NaiveDateTime, IsoWeek};
 use Date;
 use format::{Item, Numeric, Pad, Fixed};
-use format::{parse, Parsed, ParseError, ParseResult, DelayedFormat, StrftimeItems};
+use format::{parse, Parsed, ParseError, ParseResult, StrftimeItems};
+#[cfg(any(feature = "alloc", feature = "std", test))]
+use format::DelayedFormat;
 
 /// Specific formatting options for seconds. This may be extended in the
 /// future, so exhaustive matching in external code is not recommended.
@@ -367,12 +369,14 @@ impl DateTime<FixedOffset> {
 
 impl<Tz: TimeZone> DateTime<Tz> where Tz::Offset: fmt::Display {
     /// Returns an RFC 2822 date and time string such as `Tue, 1 Jul 2003 10:52:37 +0200`.
+    #[cfg(any(feature = "alloc", feature = "std", test))]
     pub fn to_rfc2822(&self) -> String {
         const ITEMS: &'static [Item<'static>] = &[Item::Fixed(Fixed::RFC2822)];
         self.format_with_items(ITEMS.iter().cloned()).to_string()
     }
 
     /// Returns an RFC 3339 and ISO 8601 date and time string such as `1996-12-19T16:39:57-08:00`.
+    #[cfg(any(feature = "alloc", feature = "std", test))]
     pub fn to_rfc3339(&self) -> String {
         const ITEMS: &'static [Item<'static>] = &[Item::Fixed(Fixed::RFC3339)];
         self.format_with_items(ITEMS.iter().cloned()).to_string()
@@ -402,6 +406,7 @@ impl<Tz: TimeZone> DateTime<Tz> where Tz::Offset: fmt::Display {
     /// assert_eq!(dt.to_rfc3339_opts(SecondsFormat::Secs, true),
     ///            "2018-01-26T10:30:09+08:00");
     /// ```
+    #[cfg(any(feature = "alloc", feature = "std", test))]
     pub fn to_rfc3339_opts(&self, secform: SecondsFormat, use_z: bool) -> String {
         use format::Numeric::*;
         use format::Pad::Zero;
@@ -453,6 +458,7 @@ impl<Tz: TimeZone> DateTime<Tz> where Tz::Offset: fmt::Display {
     }
 
     /// Formats the combined date and time with the specified formatting items.
+    #[cfg(any(feature = "alloc", feature = "std", test))]
     #[inline]
     pub fn format_with_items<'a, I>(&self, items: I) -> DelayedFormat<I>
             where I: Iterator<Item=Item<'a>> + Clone {
@@ -463,6 +469,7 @@ impl<Tz: TimeZone> DateTime<Tz> where Tz::Offset: fmt::Display {
     /// Formats the combined date and time with the specified format string.
     /// See the [`format::strftime` module](./format/strftime/index.html)
     /// on the supported escape sequences.
+    #[cfg(any(feature = "alloc", feature = "std", test))]
     #[inline]
     pub fn format<'a>(&self, fmt: &'a str) -> DelayedFormat<StrftimeItems<'a>> {
         self.format_with_items(StrftimeItems::new(fmt))
@@ -911,7 +918,7 @@ pub mod rustc_serialize {
 }
 
 /// documented at re-export site
-#[cfg(feature = "serde")]
+#[cfg(feature = "serde-1")]
 pub mod serde {
     use core::fmt;
     #[cfg(not(any(feature = "std", test)))]

src/format/mod.rs

@@ -21,13 +21,43 @@ use core::fmt;
 use core::str::FromStr;
 #[cfg(any(feature = "std", test))]
 use std::error::Error;
+#[cfg(any(feature = "alloc", feature = "std", test))]
 use alloc::boxed::Box;
-#[cfg(not(any(feature = "std", test)))]
+#[cfg(any(feature = "alloc", feature = "std", test))]
 use alloc::string::{String, ToString};
 
-use {Datelike, Timelike, Weekday, ParseWeekdayError};
+#[cfg(not(any(feature = "alloc", feature = "std", test)))]
+mod core_only {
+    /// Core only
+    #[derive(Debug, PartialEq, Eq, PartialOrd, Ord)]
+    pub struct Box<T: ?Sized>(core::marker::PhantomData<T>);
+
+    impl Box<str> {
+        /// Core only
+        pub fn len(&self) -> usize { 0 }
+    }
+
+    impl Clone for Box<str> { fn clone(&self) -> Self { Box(core::marker::PhantomData) } }
+
+    impl core::ops::Index<core::ops::RangeFull> for Box<str> {
+        type Output = str;
+        fn index(&self, _: core::ops::RangeFull) -> &Self::Output {
+            ""
+        }
+    }
+}
+
+#[cfg(not(any(feature = "alloc", feature = "std", test)))]
+use self::core_only::Box;
+
+#[cfg(any(feature = "alloc", feature = "std", test))]
+use {Datelike, Timelike};
+use {Weekday, ParseWeekdayError};
+#[cfg(any(feature = "alloc", feature = "std", test))]
 use div::{div_floor, mod_floor};
+#[cfg(any(feature = "alloc", feature = "std", test))]
 use offset::{Offset, FixedOffset};
+#[cfg(any(feature = "alloc", feature = "std", test))]
 use naive::{NaiveDate, NaiveTime};
 
 pub use self::strftime::StrftimeItems;
@@ -347,6 +377,7 @@ const BAD_FORMAT:   ParseError = ParseError(ParseErrorKind::BadFormat);
 
 /// Tries to format given arguments with given formatting items.
 /// Internally used by `DelayedFormat`.
+#[cfg(any(feature = "alloc", feature = "std", test))]
 pub fn format<'a, I>(
     w: &mut fmt::Formatter,
     date: Option<&NaiveDate>,
@@ -609,6 +640,7 @@ pub mod strftime;
 
 /// A *temporary* object which can be used as an argument to `format!` or others.
 /// This is normally constructed via `format` methods of each date and time type.
+#[cfg(any(feature = "alloc", feature = "std", test))]
 #[derive(Debug)]
 pub struct DelayedFormat<I> {
     /// The date view, if any.
@@ -621,6 +653,7 @@ pub struct DelayedFormat<I> {
     items: I,
 }
 
+#[cfg(any(feature = "alloc", feature = "std", test))]
 impl<'a, I: Iterator<Item=Item<'a>> + Clone> DelayedFormat<I> {
     /// Makes a new `DelayedFormat` value out of local date and time.
     pub fn new(date: Option<NaiveDate>, time: Option<NaiveTime>, items: I) -> DelayedFormat<I> {
@@ -636,6 +669,7 @@ impl<'a, I: Iterator<Item=Item<'a>> + Clone> DelayedFormat<I> {
     }
 }
 
+#[cfg(any(feature = "alloc", feature = "std", test))]
 impl<'a, I: Iterator<Item=Item<'a>> + Clone> fmt::Display for DelayedFormat<I> {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
         format(f, self.date.as_ref(), self.time.as_ref(), self.off.as_ref(), self.items.clone())

src/lib.rs

@@ -418,7 +418,7 @@ extern crate num_integer;
 extern crate num_traits;
 #[cfg(feature = "rustc-serialize")]
 extern crate rustc_serialize;
-#[cfg(feature = "serde")]
+#[cfg(feature = "serde-1")]
 extern crate serde as serdelib;
 #[cfg(test)]
 #[macro_use]
@@ -497,7 +497,7 @@ pub mod naive {
     ///
     /// [1]: https://serde.rs/attributes.html#field-attributes
     /// [2]: https://tools.ietf.org/html/rfc3339
-    #[cfg(feature = "serde")]
+    #[cfg(feature = "serde-1")]
     pub mod serde {
         pub use super::datetime::serde::*;
     }
@@ -515,7 +515,7 @@ mod round;
 ///
 /// [1]: https://serde.rs/attributes.html#field-attributes
 /// [2]: https://tools.ietf.org/html/rfc3339
-#[cfg(feature = "serde")]
+#[cfg(feature = "serde-1")]
 pub mod serde {
     pub use super::datetime::serde::*;
 }
@@ -703,7 +703,7 @@ impl fmt::Debug for ParseWeekdayError {
 
 // the actual `FromStr` implementation is in the `format` module to leverage the existing code
 
-#[cfg(feature = "serde")]
+#[cfg(feature = "serde-1")]
 mod weekday_serde {
     use super::Weekday;
     use core::fmt;

src/naive/date.rs

@@ -12,7 +12,9 @@ use {Weekday, Datelike};
 use div::div_mod_floor;
 use naive::{NaiveTime, NaiveDateTime, IsoWeek};
 use format::{Item, Numeric, Pad};
-use format::{parse, Parsed, ParseError, ParseResult, DelayedFormat, StrftimeItems};
+use format::{parse, Parsed, ParseError, ParseResult, StrftimeItems};
+#[cfg(any(feature = "alloc", feature = "std", test))]
+use format::DelayedFormat;
 
 use super::isoweek;
 use super::internals::{self, DateImpl, Of, Mdf, YearFlags};
@@ -916,6 +918,7 @@ impl NaiveDate {
     /// # let d = NaiveDate::from_ymd(2015, 9, 5);
     /// assert_eq!(format!("{}", d.format_with_items(fmt)), "2015-09-05");
     /// ~~~~
+    #[cfg(any(feature = "alloc", feature = "std", test))]
     #[inline]
     pub fn format_with_items<'a, I>(&self, items: I) -> DelayedFormat<I>
             where I: Iterator<Item=Item<'a>> + Clone {
@@ -954,6 +957,7 @@ impl NaiveDate {
     /// assert_eq!(format!("{}", d.format("%Y-%m-%d")), "2015-09-05");
     /// assert_eq!(format!("{}", d.format("%A, %-d %B, %C%y")), "Saturday, 5 September, 2015");
     /// ~~~~
+    #[cfg(any(feature = "alloc", feature = "std", test))]
     #[inline]
     pub fn format<'a>(&self, fmt: &'a str) -> DelayedFormat<StrftimeItems<'a>> {
         self.format_with_items(StrftimeItems::new(fmt))
@@ -1598,7 +1602,7 @@ mod rustc_serialize {
     }
 }
 
-#[cfg(feature = "serde")]
+#[cfg(feature = "serde-1")]
 mod serde {
     use core::fmt;
     #[cfg(not(any(feature = "std", test)))]

src/naive/datetime.rs

@@ -12,7 +12,9 @@ use {Weekday, Timelike, Datelike};
 use div::div_mod_floor;
 use naive::{NaiveTime, NaiveDate, IsoWeek};
 use format::{Item, Numeric, Pad, Fixed};
-use format::{parse, Parsed, ParseError, ParseResult, DelayedFormat, StrftimeItems};
+use format::{parse, Parsed, ParseError, ParseResult, StrftimeItems};
+#[cfg(any(feature = "alloc", feature = "std", test))]
+use format::DelayedFormat;
 
 /// The tight upper bound guarantees that a duration with `|Duration| >= 2^MAX_SECS_BITS`
 /// will always overflow the addition with any date and time type.
@@ -645,6 +647,7 @@ impl NaiveDateTime {
     /// # let dt = NaiveDate::from_ymd(2015, 9, 5).and_hms(23, 56, 4);
     /// assert_eq!(format!("{}", dt.format_with_items(fmt)), "2015-09-05 23:56:04");
     /// ~~~~
+    #[cfg(any(feature = "alloc", feature = "std", test))]
     #[inline]
     pub fn format_with_items<'a, I>(&self, items: I) -> DelayedFormat<I>
             where I: Iterator<Item=Item<'a>> + Clone {
@@ -683,6 +686,7 @@ impl NaiveDateTime {
     /// assert_eq!(format!("{}", dt.format("%Y-%m-%d %H:%M:%S")), "2015-09-05 23:56:04");
     /// assert_eq!(format!("{}", dt.format("around %l %p on %b %-d")), "around 11 PM on Sep 5");
     /// ~~~~
+    #[cfg(any(feature = "alloc", feature = "std", test))]
     #[inline]
     pub fn format<'a>(&self, fmt: &'a str) -> DelayedFormat<StrftimeItems<'a>> {
         self.format_with_items(StrftimeItems::new(fmt))
@@ -1661,7 +1665,7 @@ pub mod rustc_serialize {
 }
 
 /// Tools to help serializing/deserializing `NaiveDateTime`s
-#[cfg(feature = "serde")]
+#[cfg(feature = "serde-1")]
 pub mod serde {
     use core::fmt;
     #[cfg(not(any(feature = "std", test)))]

src/naive/time.rs

@@ -10,7 +10,9 @@ use oldtime::Duration as OldDuration;
 use Timelike;
 use div::div_mod_floor;
 use format::{Item, Numeric, Pad, Fixed};
-use format::{parse, Parsed, ParseError, ParseResult, DelayedFormat, StrftimeItems};
+use format::{parse, Parsed, ParseError, ParseResult, StrftimeItems};
+#[cfg(any(feature = "alloc", feature = "std", test))]
+use format::DelayedFormat;
 
 /// ISO 8601 time without timezone.
 /// Allows for the nanosecond precision and optional leap second representation.
@@ -723,6 +725,7 @@ impl NaiveTime {
     /// # let t = NaiveTime::from_hms(23, 56, 4);
     /// assert_eq!(format!("{}", t.format_with_items(fmt)), "23:56:04");
     /// ~~~~
+    #[cfg(any(feature = "alloc", feature = "std", test))]
     #[inline]
     pub fn format_with_items<'a, I>(&self, items: I) -> DelayedFormat<I>
             where I: Iterator<Item=Item<'a>> + Clone {
@@ -763,6 +766,7 @@ impl NaiveTime {
     /// assert_eq!(format!("{}", t.format("%H:%M:%S%.6f")), "23:56:04.012345");
     /// assert_eq!(format!("{}", t.format("%-I:%M %p")), "11:56 PM");
     /// ~~~~
+    #[cfg(any(feature = "alloc", feature = "std", test))]
     #[inline]
     pub fn format<'a>(&self, fmt: &'a str) -> DelayedFormat<StrftimeItems<'a>> {
         self.format_with_items(StrftimeItems::new(fmt))
@@ -1409,7 +1413,7 @@ mod rustc_serialize {
     }
 }
 
-#[cfg(feature = "serde")]
+#[cfg(feature = "serde-1")]
 mod serde {
     use core::fmt;
     #[cfg(not(any(feature = "std", test)))]