Merge pull request #408 from lucatrv/add_with_deserialize_headers

feat: add `with_deserialize_headers` method for `RangeDeserializerBui…

src/de.rs

@@ -1,6 +1,6 @@
 use serde::de::value::BorrowedStrDeserializer;
 use serde::de::{self, DeserializeOwned, DeserializeSeed, SeqAccess, Visitor};
-use serde::{self, forward_to_deserialize_any, Deserialize};
+use serde::{self, forward_to_deserialize_any, Deserialize, Deserializer};
 use std::marker::PhantomData;
 use std::{fmt, slice, str};
 
@@ -163,7 +163,7 @@ impl<'h, H: AsRef<str> + Clone + 'h> RangeDeserializerBuilder<'h, H> {
  ///
  /// Ok(())
  /// } else {
- /// return Err(From::from("expected at least one record but got none"));
+ /// Err(From::from("expected at least one record but got none"))
  /// }
  /// }
  /// ```
@@ -192,7 +192,7 @@ impl<'h, H: AsRef<str> + Clone + 'h> RangeDeserializerBuilder<'h, H> {
  ///
  /// Ok(())
  /// } else {
- /// return Err(From::from("expected at least one record but got none"));
+ /// Err(From::from("expected at least one record but got none"))
  /// }
  /// }
  /// ```
@@ -208,6 +208,87 @@ impl<'h, H: AsRef<str> + Clone + 'h> RangeDeserializerBuilder<'h, H> {
  }
 }
 
+impl<'h> RangeDeserializerBuilder<'h, &str> {
+ /// Build a `RangeDeserializer` from this configuration and keep only selected headers
+ /// from the specified deserialization struct.
+ ///
+ /// # Example
+ ///
+ /// ```
+ /// # use calamine::{open_workbook, Error, RangeDeserializerBuilder, Reader, Xlsx};
+ /// # use serde_derive::Deserialize;
+ /// #[derive(Deserialize)]
+ /// struct Record {
+ /// label: String,
+ /// value: f64,
+ /// }
+ ///
+ /// fn main() -> Result<(), Error> {
+ /// let path = format!("{}/tests/temperature.xlsx", env!("CARGO_MANIFEST_DIR"));
+ /// let mut workbook: Xlsx<_> = open_workbook(path)?;
+ /// let range = workbook.worksheet_range("Sheet1")?;
+ /// let mut iter =
+ /// RangeDeserializerBuilder::with_deserialize_headers::<Record>().from_range(&range)?;
+ ///
+ /// if let Some(result) = iter.next() {
+ /// let record: Record = result?;
+ /// assert_eq!(record.label, "celsius");
+ /// assert_eq!(record.value, 22.2222);
+ ///
+ /// Ok(())
+ /// } else {
+ /// Err(From::from("expected at least one record but got none"))
+ /// }
+ /// }
+ /// ```
+ pub fn with_deserialize_headers<'de, T>() -> Self
+ where
+ T: Deserialize<'de>,
+ {
+ struct StructFieldsDeserializer<'h> {
+ fields: &'h mut Option<&'static [&'static str]>,
+ }
+
+ impl<'de, 'h> Deserializer<'de> for StructFieldsDeserializer<'h> {
+ type Error = de::value::Error;
+
+ fn deserialize_any<V>(self, _visitor: V) -> Result<V::Value, Self::Error>
+ where
+ V: Visitor<'de>,
+ {
+ Err(de::Error::custom("I'm just here for the fields"))
+ }
+
+ fn deserialize_struct<V>(
+ self,
+ _name: &'static str,
+ fields: &'static [&'static str],
+ _visitor: V,
+ ) -> Result<V::Value, Self::Error>
+ where
+ V: Visitor<'de>,
+ {
+ *self.fields = Some(fields); // get the names of the deserialized fields
+ Err(de::Error::custom("I'm just here for the fields"))
+ }
+
+ serde::forward_to_deserialize_any! {
+ bool i8 i16 i32 i64 u8 u16 u32 u64 f32 f64 char str string bytes
+ byte_buf option unit unit_struct newtype_struct seq tuple
+ tuple_struct map enum identifier ignored_any
+ }
+ }
+
+ let mut serialized_names = None;
+ let _ = T::deserialize(StructFieldsDeserializer {
+ fields: &mut serialized_names,
+ });
+ let headers = serialized_names.unwrap_or_default();
+
+ Self::with_headers(headers)
+ }
+}
+
 /// A configured `Range` deserializer.
 ///
 /// # Example