From f66d8bcf33530c858a502bfa170f2383a8cbc204 Mon Sep 17 00:00:00 2001
From: Alex Crichton <alex@alexcrichton.com>
Date: Sun, 29 Jan 2017 16:53:20 -0800
Subject: Rewrite crate with serde support from ground up

This commit completely rewrites this crate from the ground up,
supporting serde at the lowest levels as I believe serde support was
intended to do. This is a major change from the previous versions of
this crate, with a summary of changes being:

* Serialization directly to TOML is now supported without going through
  a `Value` first.

* Deserialization directly from TOML is now supported without going
  through a `Value`. Note that due to the TOML format some values still
  are buffered in intermediate memory, but overall this should be at a
  minimum now.

* The API of `Value` was overhauled to match the API of
  `serde_json::Value`. The changes here were to:

  * Add `is_*` accessors
  * Add `get` and `get_mut` for one-field lookups.
  * Implement panicking lookups through `Index`

  The old `index` methods are now gone in favor of `get` and `Index`
  implementations.

* A `Datetime` type has been added to represent a TOML datetime in a
  first-class fashion. Currently this type provides no accessors other
  than a `Display` implementation, but the idea is that this will grow
  support over time for decomposing the date.

* Support for the `rustc-serialize` crate has been dropped, that'll stay
  on the 0.2 and 0.1 release trains.

* This crate no longer supports the detection of unused fields, for that though
  you can use the `serde_ignored` crate on crates.io
---
 src/datetime.rs | 424 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 424 insertions(+)
 create mode 100644 src/datetime.rs

(limited to 'src/datetime.rs')

diff --git a/src/datetime.rs b/src/datetime.rs
new file mode 100644
index 0000000..7a618dc
--- /dev/null
+++ b/src/datetime.rs
@@ -0,0 +1,424 @@
+use std::fmt;
+use std::str::{self, FromStr};
+use std::error;
+
+use serde::{de, ser};
+
+/// A parsed TOML datetime value
+///
+/// This structure is intended to represent the datetime primitive type that can
+/// be encoded into TOML documents. This type is a parsed version that contains
+/// all metadata internally.
+///
+/// Currently this type is intentionally conservative and only supports
+/// `to_string` as an accessor. Over time though it's intended that it'll grow
+/// more support!
+///
+/// Note that if you're using `Deserialize` to deserialize a TOML document, you
+/// can use this as a placeholder for where you're expecting a datetime to be
+/// specified.
+///
+/// Also note though that while this type implements `Serialize` and
+/// `Deserialize` it's only recommended to use this type with the TOML format,
+/// otherwise encoded in other formats it may look a little odd.
+#[derive(PartialEq, Clone)]
+pub struct Datetime {
+    date: Option<Date>,
+    time: Option<Time>,
+    offset: Option<Offset>,
+}
+
+/// Error returned from parsing a `Datetime` in the `FromStr` implementation.
+#[derive(Debug, Clone)]
+pub struct DatetimeParseError {
+    _private: (),
+}
+
+// Currently serde itself doesn't have a datetime type, so we map our `Datetime`
+// to a special valid in the serde data model. Namely one with thiese special
+// fields/struct names.
+//
+// In general the TOML encoder/decoder will catch this and not literally emit
+// these strings but rather emit datetimes as they're intended.
+pub const SERDE_STRUCT_FIELD_NAME: &'static str = "$__toml_private_datetime";
+pub const SERDE_STRUCT_NAME: &'static str = "$__toml_private_Datetime";
+
+#[derive(PartialEq, Clone)]
+struct Date {
+    year: u16,
+    month: u8,
+    day: u8,
+}
+
+#[derive(PartialEq, Clone)]
+struct Time {
+    hour: u8,
+    minute: u8,
+    second: u8,
+    secfract: Option<f64>,
+}
+
+#[derive(PartialEq, Clone)]
+enum Offset {
+    Z,
+    Custom { hours: i8, minutes: u8 },
+}
+
+impl fmt::Debug for Datetime {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        fmt::Display::fmt(self, f)
+    }
+}
+
+impl fmt::Display for Datetime {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        if let Some(ref date) = self.date {
+            write!(f, "{}", date)?;
+        }
+        if let Some(ref time) = self.time {
+            if self.date.is_some() {
+                write!(f, "T")?;
+            }
+            write!(f, "{}", time)?;
+        }
+        if let Some(ref offset) = self.offset {
+            write!(f, "{}", offset)?;
+        }
+        Ok(())
+    }
+}
+
+impl fmt::Display for Date {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        write!(f, "{:04}-{:02}-{:02}", self.year, self.month, self.day)
+    }
+}
+
+impl fmt::Display for Time {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        write!(f, "{:02}:{:02}:{:02}", self.hour, self.minute, self.second)?;
+        if let Some(i) = self.secfract {
+            let s = format!("{}", i);
+            write!(f, "{}", s.trim_left_matches("0"))?;
+        }
+        Ok(())
+    }
+}
+
+impl fmt::Display for Offset {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        match *self {
+            Offset::Z => write!(f, "Z"),
+            Offset::Custom { hours, minutes } => {
+                write!(f, "{:+03}:{:02}", hours, minutes)
+            }
+        }
+    }
+}
+
+impl FromStr for Datetime {
+    type Err = DatetimeParseError;
+
+    fn from_str(date: &str) -> Result<Datetime, DatetimeParseError> {
+        // Accepted formats:
+        //
+        // 0000-00-00T00:00:00.00Z
+        // 0000-00-00T00:00:00.00
+        // 0000-00-00
+        // 00:00:00.00
+        if date.len() < 3 {
+            return Err(DatetimeParseError { _private: () })
+        }
+        let mut offset_allowed = true;
+        let mut chars = date.chars();
+
+        // First up, parse the full date if we can
+        let full_date = if chars.clone().nth(2) == Some(':') {
+            offset_allowed = false;
+            None
+        } else {
+            let y1 = digit(&mut chars)? as u16;
+            let y2 = digit(&mut chars)? as u16;
+            let y3 = digit(&mut chars)? as u16;
+            let y4 = digit(&mut chars)? as u16;
+
+            match chars.next() {
+                Some('-') => {}
+                _ => return Err(DatetimeParseError { _private: () }),
+            }
+
+            let m1 = digit(&mut chars)?;
+            let m2 = digit(&mut chars)?;
+
+            match chars.next() {
+                Some('-') => {}
+                _ => return Err(DatetimeParseError { _private: () }),
+            }
+
+            let d1 = digit(&mut chars)?;
+            let d2 = digit(&mut chars)?;
+
+            let date = Date {
+                year: y1 * 1000 + y2 * 100 + y3 * 10 + y4,
+                month: m1 * 10 + m2,
+                day: d1 * 10 + d2,
+            };
+
+            if date.month < 1 || date.month > 12 {
+                return Err(DatetimeParseError { _private: () })
+            }
+            if date.day < 1 || date.day > 31 {
+                return Err(DatetimeParseError { _private: () })
+            }
+
+            Some(date)
+        };
+
+        // Next parse the "partial-time" if available
+        let partial_time = if full_date.is_some() &&
+                              chars.clone().next() == Some('T') {
+            chars.next();
+            true
+        } else if full_date.is_none() {
+            true
+        } else {
+            false
+        };
+        let time = if partial_time {
+            let h1 = digit(&mut chars)?;
+            let h2 = digit(&mut chars)?;
+            match chars.next() {
+                Some(':') => {}
+                _ => return Err(DatetimeParseError { _private: () }),
+            }
+            let m1 = digit(&mut chars)?;
+            let m2 = digit(&mut chars)?;
+            match chars.next() {
+                Some(':') => {}
+                _ => return Err(DatetimeParseError { _private: () }),
+            }
+            let s1 = digit(&mut chars)?;
+            let s2 = digit(&mut chars)?;
+
+            let secfract = if chars.clone().next() == Some('.') {
+                chars.next();
+                let mut first = true;
+                let whole = chars.as_str();
+                let mut end = whole.len();
+                for (i, c) in whole.char_indices() {
+                    match c {
+                        '0' ... '9' => {}
+                        _ => {
+                            end = i;
+                            break
+                        }
+                    }
+                    first = false;
+                }
+                if first {
+                    return Err(DatetimeParseError { _private: () })
+                }
+                chars = whole[end..].chars();
+                match format!("0.{}", &whole[..end]).parse() {
+                    Ok(f) => Some(f),
+                    Err(_) => return Err(DatetimeParseError { _private: () }),
+                }
+            } else {
+                None
+            };
+
+            let time = Time {
+                hour: h1 * 10 + h2,
+                minute: m1 * 10 + m2,
+                second: s1 * 10 + s2,
+                secfract: secfract,
+            };
+
+            if time.hour > 24 {
+                return Err(DatetimeParseError { _private: () })
+            }
+            if time.minute > 59 {
+                return Err(DatetimeParseError { _private: () })
+            }
+            if time.second > 60 {
+                return Err(DatetimeParseError { _private: () })
+            }
+
+            Some(time)
+        } else {
+            offset_allowed = false;
+            None
+        };
+
+        // And finally, parse the offset
+        let offset = if offset_allowed {
+            let next = chars.clone().next();
+            if next == Some('Z') {
+                chars.next();
+                Some(Offset::Z)
+            } else if next.is_none() {
+                None
+            } else {
+                let sign = match next {
+                    Some('+') => 1,
+                    Some('-') => -1,
+                    _ => return Err(DatetimeParseError { _private: () }),
+                };
+                chars.next();
+                let h1 = digit(&mut chars)? as i8;
+                let h2 = digit(&mut chars)? as i8;
+                match chars.next() {
+                    Some(':') => {}
+                    _ => return Err(DatetimeParseError { _private: () }),
+                }
+                let m1 = digit(&mut chars)?;
+                let m2 = digit(&mut chars)?;
+
+                Some(Offset::Custom {
+                    hours: sign * (h1 * 10 + h2),
+                    minutes: m1 * 10 + m2,
+                })
+            }
+        } else {
+            None
+        };
+
+        // Return an error if we didn't hit eof, otherwise return our parsed
+        // date
+        if chars.next().is_some() {
+            return Err(DatetimeParseError { _private: () })
+        }
+
+        Ok(Datetime {
+            date: full_date,
+            time: time,
+            offset: offset,
+        })
+    }
+}
+
+fn digit(chars: &mut str::Chars) -> Result<u8, DatetimeParseError> {
+    match chars.next() {
+        Some(c) if '0' <= c && c <= '9' => Ok(c as u8 - '0' as u8),
+        _ => Err(DatetimeParseError { _private: () }),
+    }
+}
+
+impl ser::Serialize for Datetime {
+    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
+        where S: ser::Serializer
+    {
+        use serde::ser::SerializeStruct;
+
+        let mut s = serializer.serialize_struct(SERDE_STRUCT_NAME, 1)?;
+        s.serialize_field(SERDE_STRUCT_FIELD_NAME, &self.to_string())?;
+        s.end()
+    }
+}
+
+impl de::Deserialize for Datetime {
+    fn deserialize<D>(deserializer: D) -> Result<Datetime, D::Error>
+        where D: de::Deserializer
+    {
+        struct DatetimeVisitor;
+
+        impl de::Visitor for DatetimeVisitor {
+            type Value = Datetime;
+
+            fn expecting(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
+                formatter.write_str("a TOML datetime")
+            }
+
+            fn visit_map<V>(self, mut visitor: V) -> Result<Datetime, V::Error>
+                where V: de::MapVisitor
+            {
+                let value = visitor.visit_key::<DatetimeKey>()?;
+                if value.is_none() {
+                    return Err(de::Error::custom("datetime key not found"))
+                }
+                let v: DatetimeFromString = visitor.visit_value()?;
+                Ok(v.value)
+
+            }
+        }
+
+        static FIELDS: [&'static str; 1] = [SERDE_STRUCT_FIELD_NAME];
+        deserializer.deserialize_struct(SERDE_STRUCT_NAME,
+                                        &FIELDS,
+                                        DatetimeVisitor)
+    }
+}
+
+struct DatetimeKey;
+
+impl de::Deserialize for DatetimeKey {
+    fn deserialize<D>(deserializer: D) -> Result<DatetimeKey, D::Error>
+        where D: de::Deserializer
+    {
+        struct FieldVisitor;
+
+        impl de::Visitor for FieldVisitor {
+            type Value = ();
+
+            fn expecting(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
+                formatter.write_str("a valid datetime field")
+            }
+
+            fn visit_str<E>(self, s: &str) -> Result<(), E>
+                where E: de::Error
+            {
+                if s == SERDE_STRUCT_FIELD_NAME {
+                    Ok(())
+                } else {
+                    Err(de::Error::custom("expected field with custom name"))
+                }
+            }
+        }
+
+        deserializer.deserialize_struct_field(FieldVisitor)?;
+        Ok(DatetimeKey)
+    }
+}
+
+pub struct DatetimeFromString {
+    pub value: Datetime,
+}
+
+impl de::Deserialize for DatetimeFromString {
+    fn deserialize<D>(deserializer: D) -> Result<DatetimeFromString, D::Error>
+        where D: de::Deserializer
+    {
+        struct Visitor;
+
+        impl de::Visitor for Visitor {
+            type Value = DatetimeFromString;
+
+            fn expecting(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
+                formatter.write_str("string containing a datetime")
+            }
+
+            fn visit_str<E>(self, s: &str) -> Result<DatetimeFromString, E>
+                where E: de::Error,
+            {
+                match s.parse() {
+                    Ok(date) => Ok(DatetimeFromString { value: date }),
+                    Err(e) => Err(de::Error::custom(e)),
+                }
+            }
+        }
+
+        deserializer.deserialize_str(Visitor)
+    }
+}
+
+impl fmt::Display for DatetimeParseError {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        "failed to parse datetime".fmt(f)
+    }
+}
+
+impl error::Error for DatetimeParseError {
+    fn description(&self) -> &str {
+        "failed to parse datetime"
+    }
+}
-- 
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