read_value()/write_value(): put behind feature postcard-values

Cargo.toml

@@ -11,7 +11,11 @@ categories = ["embedded", "database"]
 license = "GPL-3"
 edition = "2018"
 
+[features]
+default = ["postcard-values"]
+postcard-values = ["postcard", "serde"]
+
 [dependencies]
 byteorder = { version = "1", default-features = false }
-serde = { version = "1.0", default-features = false }
+serde = { version = "1.0", default-features = false, optional = true }
-postcard = "0.5"
+postcard = { version = "0.5", optional = true }

src/error.rs

@@ -4,7 +4,9 @@ use core::{fmt, str};
 pub enum Error<B> {
     Read(ReadError),
     Write(WriteError<B>),
+    #[cfg(feature = "postcard-values")]
     Encode(postcard::Error),
+    #[cfg(feature = "postcard-values")]
     Decode(postcard::Error),
 }
 

src/lib.rs

@@ -2,6 +2,7 @@
 
 use core::{mem::size_of, str};
 use byteorder::{ByteOrder, BigEndian};
+#[cfg(feature = "postcard-values")]
 use serde::{Deserialize, Serialize};
 
 mod error;
@@ -59,10 +60,12 @@ impl<B: StoreBackend> Store<B> {
                       .map(|value| str::from_utf8(value)
                            .map_err(ReadError::Utf8Error)
                       )
-                      .transpose())
+                      .transpose()
+            )
     }
 
     /// read from `key`, decode with `postcard`
+    #[cfg(feature = "postcard-values")]
     pub fn read_value<'a, T: Deserialize<'a>>(&'a self, key: &str) -> Result<Option<T>, Error<B::Error>> {
         self.read(key)?
             .map(
@@ -159,6 +162,7 @@ impl<B: StoreBackend> Store<B> {
     }
 
     /// encode with `postcard`, write at `key`
+    #[cfg(feature = "postcard-values")]
     pub fn write_value<T: Serialize>(&mut self, key: &str, value: T) -> Result<(), Error<B::Error>> {
         let mut buf = [0; 64];
         let data = postcard::to_slice(&value, &mut buf)

src/test.rs

@@ -74,6 +74,7 @@ fn write_read_str_utf8() {
 }
 
 #[test]
+#[cfg(feature = "postcard-values")]
 fn write_read_value_str() {
     let mut store = make_store();
     store.write_value("foo", "bar").unwrap();
@@ -81,6 +82,7 @@ fn write_read_value_str() {
 }
 
 #[test]
+#[cfg(feature = "postcard-values")]
 fn write_read_value_u32() {
     let mut store = make_store();
     store.write_value("foo", 42005u32).unwrap();
@@ -88,6 +90,7 @@ fn write_read_value_u32() {
 }
 
 #[test]
+#[cfg(feature = "postcard-values")]
 fn write_read_value_i64() {
     let mut store = make_store();
     store.write_value("foo", -99999999i64).unwrap();
@@ -95,6 +98,7 @@ fn write_read_value_i64() {
 }
 
 #[test]
+#[cfg(feature = "postcard-values")]
 fn write_read_value_f32() {
     let mut store = make_store();
     store.write_value("foo", 3.75e17f32).unwrap();
@@ -102,6 +106,7 @@ fn write_read_value_f32() {
 }
 
 #[test]
+#[cfg(feature = "postcard-values")]
 fn write_read_value_f64() {
     let mut store = make_store();
     store.write_value("foo", -1.999e-13f64).unwrap();