RUST-1406 Add type-specific errors to standard error type (#555)

Author: isabelatkinson

src/binary.rs

@@ -1,13 +1,18 @@
 #! Module containing functionality related to BSON binary values.
-
 mod vector;
 
-use crate::{base64, spec::BinarySubtype, RawBinaryRef};
 use std::{
-    error,
+    convert::TryFrom,
     fmt::{self, Display},
 };
 
+use crate::{
+    base64,
+    error::{Error, Result},
+    spec::BinarySubtype,
+    RawBinaryRef,
+};
+
 pub use vector::{PackedBitVector, Vector};
 
 /// Represents a BSON binary value.
@@ -37,7 +42,7 @@ impl Binary {
     /// [`BinarySubtype::Generic`].
     ///
     /// ```rust
-    /// # use bson::{Binary, binary::Result};
+    /// # use bson::{Binary, error::Result};
     /// # fn example() -> Result<()> {
     /// let input = base64::encode("hello");
     /// let binary = Binary::from_base64(input, None)?;
@@ -50,9 +55,7 @@ impl Binary {
         input: impl AsRef<str>,
         subtype: impl Into<Option<BinarySubtype>>,
     ) -> Result<Self> {
-        let bytes = base64::decode(input.as_ref()).map_err(|e| Error::DecodingError {
-            message: e.to_string(),
-        })?;
+        let bytes = base64::decode(input.as_ref()).map_err(Error::binary)?;
         let subtype = match subtype.into() {
             Some(s) => s,
             None => BinarySubtype::Generic,
@@ -97,27 +100,3 @@ impl Binary {
         }
     }
 }
-
-/// Possible errors that can arise during [`Binary`] construction.
-#[derive(Clone, Debug)]
-#[non_exhaustive]
-pub enum Error {
-    /// While trying to decode from base64, an error was returned.
-    DecodingError { message: String },
-
-    /// A [`Vector`]-related error occurred.
-    Vector { message: String },
-}
-
-impl error::Error for Error {}
-
-impl std::fmt::Display for Error {
-    fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
-        match self {
-            Error::DecodingError { message } => fmt.write_str(message),
-            Error::Vector { message } => fmt.write_str(message),
-        }
-    }
-}
-
-pub type Result<T> = std::result::Result<T, Error>;

src/binary/vector.rs

@@ -23,7 +23,7 @@ const PACKED_BIT: u8 = 0x10;
 ///
 /// ```rust
 /// # use serde::{Serialize, Deserialize};
-/// # use bson::{binary::{Result, Vector}, spec::ElementType};
+/// # use bson::{binary::Vector, error::Result, spec::ElementType};
 /// #[derive(Serialize, Deserialize)]
 /// struct Data {
 ///     vector: Vector,
@@ -64,7 +64,7 @@ impl PackedBitVector {
     /// single-bit elements in little-endian format. For example, the following vector:
     ///
     /// ```rust
-    /// # use bson::binary::{Result, PackedBitVector};
+    /// # use bson::{binary::PackedBitVector, error::Result};
     /// # fn main() -> Result<()> {
     /// let packed_bits = vec![238, 224];
     /// let vector = PackedBitVector::new(packed_bits, 0)?;
@@ -91,17 +91,14 @@ impl PackedBitVector {
     pub fn new(vector: Vec<u8>, padding: impl Into<Option<u8>>) -> Result<Self> {
         let padding = padding.into().unwrap_or(0);
         if !(0..8).contains(&padding) {
-            return Err(Error::Vector {
-                message: format!("padding must be within 0-7 inclusive, got {}", padding),
-            });
+            return Err(Error::binary(format!(
+                "vector padding must be within 0-7 inclusive, got {padding}"
+            )));
         }
         if padding != 0 && vector.is_empty() {
-            return Err(Error::Vector {
-                message: format!(
-                    "cannot specify non-zero padding if the provided vector is empty, got {}",
-                    padding
-                ),
-            });
+            return Err(Error::binary(format!(
+                "cannot specify non-zero padding if the provided vector is empty, got {padding}",
+            )));
         }
         Ok(Self { vector, padding })
     }
@@ -115,24 +112,19 @@ impl Vector {
         let bytes = bytes.as_ref();
 
         if bytes.len() < 2 {
-            return Err(Error::Vector {
-                message: format!(
-                    "the provided bytes must have a length of at least 2, got {}",
-                    bytes.len()
-                ),
-            });
+            return Err(Error::binary(format!(
+                "the provided vector bytes must have a length of at least 2, got {}",
+                bytes.len()
+            )));
         }
 
         let d_type = bytes[0];
         let padding = bytes[1];
         if d_type != PACKED_BIT && padding != 0 {
-            return Err(Error::Vector {
-                message: format!(
-                    "padding can only be specified for a packed bit vector (data type {}), got \
-                     type {}",
-                    PACKED_BIT, d_type
-                ),
-            });
+            return Err(Error::binary(format!(
+                "padding can only be specified for a packed bit vector (data type {}), got type {}",
+                PACKED_BIT, d_type
+            )));
         }
         let number_bytes = &bytes[2..];
 
@@ -149,11 +141,11 @@ impl Vector {
 
                 let mut vector = Vec::new();
                 for chunk in number_bytes.chunks(F32_BYTES) {
-                    let bytes: [u8; F32_BYTES] = chunk.try_into().map_err(|_| Error::Vector {
-                        message: format!(
+                    let bytes: [u8; F32_BYTES] = chunk.try_into().map_err(|_| {
+                        Error::binary(format!(
                             "f32 vector values must be {} bytes, got {:?}",
                             F32_BYTES, chunk,
-                        ),
+                        ))
                     })?;
                     vector.push(f32::from_le_bytes(bytes));
                 }
@@ -163,9 +155,9 @@ impl Vector {
                 let packed_bit_vector = PackedBitVector::new(number_bytes.to_vec(), padding)?;
                 Ok(Self::PackedBit(packed_bit_vector))
             }
-            other => Err(Error::Vector {
-                message: format!("unsupported vector data type: {}", other),
-            }),
+            other => Err(Error::binary(format!(
+                "unsupported vector data type: {other}"
+            ))),
         }
     }
 
@@ -228,9 +220,10 @@ impl TryFrom<&Binary> for Vector {
 
     fn try_from(binary: &Binary) -> Result<Self> {
         if binary.subtype != BinarySubtype::Vector {
-            return Err(Error::Vector {
-                message: format!("expected vector binary subtype, got {:?}", binary.subtype),
-            });
+            return Err(Error::binary(format!(
+                "expected vector binary subtype, got {:?}",
+                binary.subtype
+            )));
         }
         Self::from_bytes(&binary.bytes)
     }

src/datetime.rs

@@ -1,25 +1,24 @@
 //! Module containing functionality related to BSON DateTimes.
 //! For more information, see the documentation for the [`DateTime`] type.
+pub(crate) mod builder;
 
 use std::{
     convert::TryInto,
-    error,
     fmt::{self, Display},
-    result,
     time::{Duration, SystemTime},
 };
 
-pub(crate) mod builder;
-pub use crate::datetime::builder::DateTimeBuilder;
-use time::format_description::well_known::Rfc3339;
-
 #[cfg(feature = "chrono-0_4")]
 use chrono::{LocalResult, TimeZone, Utc};
 #[cfg(all(
     feature = "serde_with-3",
     any(feature = "chrono-0_4", feature = "time-0_3")
 ))]
 use serde::{Deserialize, Deserializer, Serialize};
+use time::format_description::well_known::Rfc3339;
+
+pub use crate::datetime::builder::DateTimeBuilder;
+use crate::error::{Error, Result};
 
 /// Struct representing a BSON datetime.
 /// Note: BSON datetimes have millisecond precision.
@@ -388,21 +387,13 @@ impl crate::DateTime {
 
     /// Convert this [`DateTime`] to an RFC 3339 formatted string.
     pub fn try_to_rfc3339_string(self) -> Result<String> {
-        self.to_time_0_3()
-            .format(&Rfc3339)
-            .map_err(|e| Error::CannotFormat {
-                message: e.to_string(),
-            })
+        self.to_time_0_3().format(&Rfc3339).map_err(Error::datetime)
     }
 
     /// Convert the given RFC 3339 formatted string to a [`DateTime`], truncating it to millisecond
     /// precision.
     pub fn parse_rfc3339_str(s: impl AsRef<str>) -> Result<Self> {
-        let odt = time::OffsetDateTime::parse(s.as_ref(), &Rfc3339).map_err(|e| {
-            Error::InvalidTimestamp {
-                message: e.to_string(),
-            }
-        })?;
+        let odt = time::OffsetDateTime::parse(s.as_ref(), &Rfc3339).map_err(Error::datetime)?;
         Ok(Self::from_time_0_3(odt))
     }
 
@@ -543,30 +534,3 @@ impl serde_with::SerializeAs<time::OffsetDateTime> for crate::DateTime {
         dt.serialize(serializer)
     }
 }
-
-/// Errors that can occur during [`DateTime`] construction and generation.
-#[derive(Clone, Debug)]
-#[non_exhaustive]
-pub enum Error {
-    /// Error returned when an invalid datetime format is provided to a conversion method.
-    #[non_exhaustive]
-    InvalidTimestamp { message: String },
-    /// Error returned when a [`DateTime`] cannot be represented in a particular format.
-    #[non_exhaustive]
-    CannotFormat { message: String },
-}
-
-/// Alias for `Result<T, DateTime::Error>`
-pub type Result<T> = result::Result<T, Error>;
-
-impl fmt::Display for Error {
-    fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
-        match self {
-            Error::InvalidTimestamp { message } | Error::CannotFormat { message } => {
-                write!(fmt, "{}", message)
-            }
-        }
-    }
-}
-
-impl error::Error for Error {}

src/datetime/builder.rs

@@ -1,7 +1,12 @@
-use super::*;
 use std::convert::TryFrom;
+
 use time::Date;
 
+use crate::{
+    datetime::DateTime,
+    error::{Error, Result},
+};
+
 /// Builder for constructing a BSON [`DateTime`]
 pub struct DateTimeBuilder<Y = NoYear, M = NoMonth, D = NoDay> {
     pub(crate) year: Y,
@@ -169,19 +174,16 @@ impl DateTimeBuilder<Year, Month, Day> {
     ///
     /// Note: You cannot call `build()` before setting at least the year, month and day.
     pub fn build(self) -> Result<DateTime> {
-        let err = |e: time::error::ComponentRange| Error::InvalidTimestamp {
-            message: e.to_string(),
-        };
-        let month = time::Month::try_from(self.month.0).map_err(err)?;
+        let month = time::Month::try_from(self.month.0).map_err(Error::datetime)?;
         let dt = Date::from_calendar_date(self.year.0, month, self.day.0)
-            .map_err(err)?
+            .map_err(Error::datetime)?
             .with_hms_milli(
                 self.hour.unwrap_or(0),
                 self.minute.unwrap_or(0),
                 self.second.unwrap_or(0),
                 self.millisecond.unwrap_or(0),
             )
-            .map_err(err)?;
+            .map_err(Error::datetime)?;
         Ok(DateTime::from_time_private(dt.assume_utc()))
     }
 }