Add support for no-std usages of capnp crate.

Author: dwrensha

.travis.yml

@@ -3,10 +3,10 @@ sudo: false
 language: rust
 matrix:
   include:
-    - rust: stable
+    #- rust: stable
     - rust: beta
     - rust: nightly
-    - rust: 1.40.0
+    #- rust: 1.44.0
 env:
   global:
     - export PATH="$PATH:$HOME/bin"
@@ -26,6 +26,9 @@ install:
   - cd ../
 
 script:
+  - cd capnp
+  - cargo test --no-default-features
+  - cd ../
   - cargo build --all
   - cargo test --all
   - ./target/debug/addressbook write | ./target/debug/addressbook read

capnp/Cargo.toml

@@ -25,9 +25,13 @@ quickcheck = { version = "0.9", optional = true }
 quickcheck = "0.9"
 
 [features]
+default = ["std"]
+
 rpc_try = []
 
 # If enabled, relaxes alignment requirements on segments.
 # This has a performance cost on some targets (e.g. ARMv6).
 unaligned = []
 
+std = []
+

capnp/src/any_pointer.rs

@@ -21,6 +21,9 @@
 
 //! Dynamically typed value.
 
+use alloc::boxed::Box;
+use alloc::vec::Vec;
+
 use crate::capability::FromClientHook;
 use crate::private::capability::{ClientHook, PipelineHook, PipelineOp};
 use crate::private::layout::{PointerReader, PointerBuilder};

capnp/src/any_pointer_list.rs

@@ -124,7 +124,7 @@ impl <'a> crate::traits::SetPointerBuilder<Builder<'a>> for Reader<'a> {
     }
 }
 
-impl <'a> ::std::iter::IntoIterator for Reader<'a> {
+impl <'a> core::iter::IntoIterator for Reader<'a> {
     type Item = Result<crate::any_pointer::Reader<'a>>;
     type IntoIter = ListIter<Reader<'a>, Self::Item>;
 

capnp/src/capability.rs

@@ -23,19 +23,18 @@
 //!
 //! Roughly corresponds to capability.h in the C++ implementation.
 
+use alloc::boxed::Box;
+use core::future::{Future};
+use core::pin::{Pin};
+use core::marker::{PhantomData, Unpin};
+use core::task::Poll;
+#[cfg(feature = "rpc_try")]
+use core::ops::Try;
+
 use crate::{any_pointer, Error, MessageSize};
 use crate::traits::{Pipelined, Owned};
 use crate::private::capability::{ClientHook, ParamsHook, RequestHook, ResponseHook, ResultsHook};
 
-use std::future::{Future};
-use std::pin::{Pin};
-use std::marker::Unpin;
-use std::task::Poll;
-#[cfg(feature = "rpc_try")]
-use std::ops::Try;
-
-use std::marker::PhantomData;
-
 /// A computation that might eventually resolve to a value of type `T` or to an error
 ///  of type `E`. Dropping the promise cancels the computation.
 #[must_use = "futures do nothing unless polled"]
@@ -45,7 +44,7 @@ pub struct Promise<T, E> {
 
 enum PromiseInner<T, E> {
     Immediate(Result<T,E>),
-    Deferred(Pin<Box<dyn Future<Output=std::result::Result<T,E>> + 'static>>),
+    Deferred(Pin<Box<dyn Future<Output=core::result::Result<T,E>> + 'static>>),
     Empty,
 }
 
@@ -62,21 +61,21 @@ impl <T, E> Promise<T, E> {
     }
 
     pub fn from_future<F>(f: F) -> Promise<T, E>
-        where F: Future<Output=std::result::Result<T,E>> + 'static
+        where F: Future<Output=core::result::Result<T,E>> + 'static
     {
         Promise { inner: PromiseInner::Deferred(Box::pin(f)) }
     }
 }
 
 impl <T, E> Future for Promise<T, E>
 {
-    type Output = std::result::Result<T,E>;
+    type Output = core::result::Result<T,E>;
 
-    fn poll(self: Pin<&mut Self>, cx: &mut ::std::task::Context) -> Poll<Self::Output> {
+    fn poll(self: Pin<&mut Self>, cx: &mut ::core::task::Context) -> Poll<Self::Output> {
         match self.get_mut().inner {
             PromiseInner::Empty => panic!("Promise polled after done."),
             ref mut imm @ PromiseInner::Immediate(_) => {
-                match std::mem::replace(imm, PromiseInner::Empty) {
+                match core::mem::replace(imm, PromiseInner::Empty) {
                     PromiseInner::Immediate(r) => Poll::Ready(r),
                     _ => unreachable!(),
                 }
@@ -254,7 +253,7 @@ pub trait Server {
 /// Trait to track the relationship between generated Server traits and Client structs.
 pub trait FromServer<S> : FromClientHook {
     // Implemented by the generated ServerDispatch struct.
-    type Dispatch: Server + 'static + std::ops::DerefMut<Target=S>;
+    type Dispatch: Server + 'static + core::ops::DerefMut<Target=S>;
 
     fn from_server(s: S) -> Self::Dispatch;
 }

capnp/src/capability_list.rs

@@ -20,7 +20,8 @@
 
 //! List of capabilities.
 
-use std::marker::PhantomData;
+use alloc::boxed::Box;
+use core::marker::PhantomData;
 
 use crate::capability::{FromClientHook};
 use crate::private::capability::ClientHook;
@@ -152,7 +153,7 @@ impl <'a, T> crate::traits::SetPointerBuilder<Builder<'a, T>> for Reader<'a, T>
     }
 }
 
-impl <'a, T> ::std::iter::IntoIterator for Reader<'a, T>
+impl <'a, T> ::core::iter::IntoIterator for Reader<'a, T>
     where T: FromClientHook
 {
     type Item = Result<T>;

capnp/src/constant.rs

@@ -23,7 +23,7 @@
 //! `constant::Reader` does not do bounds-checking, so it is unsafe to
 //! manually construct one of these.
 
-use std::marker::PhantomData;
+use core::marker::PhantomData;
 
 use crate::any_pointer;
 use crate::private::layout::PointerReader;

capnp/src/data.rs

@@ -35,7 +35,7 @@ impl<'a> crate::traits::Owned<'a> for Owned {
 pub type Reader<'a> = &'a [u8];
 
 pub fn new_reader<'a>(p : *const u8, len : u32) -> Reader<'a> {
-    unsafe { ::std::slice::from_raw_parts(p, len as usize) }
+    unsafe { ::core::slice::from_raw_parts(p, len as usize) }
 }
 
 impl <'a> crate::traits::FromPointerReader<'a> for Reader<'a> {
@@ -47,7 +47,7 @@ impl <'a> crate::traits::FromPointerReader<'a> for Reader<'a> {
 pub type Builder<'a> = &'a mut [u8];
 
 pub fn new_builder<'a>(p : *mut u8, len : u32) -> Builder<'a> {
-    unsafe { ::std::slice::from_raw_parts_mut(p, len as usize) }
+    unsafe { ::core::slice::from_raw_parts_mut(p, len as usize) }
 }
 
 impl <'a> crate::traits::FromPointerBuilder<'a> for Builder<'a> {

capnp/src/data_list.rs

@@ -133,7 +133,7 @@ impl <'a> crate::traits::SetPointerBuilder<Builder<'a>> for Reader<'a> {
     }
 }
 
-impl <'a> ::std::iter::IntoIterator for Reader<'a> {
+impl <'a> ::core::iter::IntoIterator for Reader<'a> {
     type Item = Result<crate::data::Reader<'a>>;
     type IntoIter = ListIter<Reader<'a>, Self::Item>;
 

capnp/src/enum_list.rs

@@ -27,7 +27,7 @@ use crate::private::layout::{ListReader, ListBuilder, PointerReader, PointerBuil
                              TwoBytes, PrimitiveElement};
 use crate::{NotInSchema, Result};
 
-use std::marker::PhantomData;
+use core::marker::PhantomData;
 
 #[derive(Clone, Copy)]
 pub struct Owned<T> {
@@ -52,7 +52,7 @@ impl <'a, T: FromU16> Reader<'a, T> {
 
     pub fn len(&self) -> u32 { self.reader.len() }
 
-    pub fn iter(self) -> ListIter<Reader<'a, T>, ::std::result::Result<T, NotInSchema>>{
+    pub fn iter(self) -> ListIter<Reader<'a, T>, ::core::result::Result<T, NotInSchema>>{
         let l = self.len();
         ListIter::new(self, l)
     }
@@ -65,14 +65,14 @@ impl <'a, T : FromU16> FromPointerReader<'a> for Reader<'a, T> {
     }
 }
 
-impl <'a, T: FromU16>  IndexMove<u32, ::std::result::Result<T, NotInSchema>> for Reader<'a, T>{
-    fn index_move(&self, index: u32) -> ::std::result::Result<T, NotInSchema> {
+impl <'a, T: FromU16>  IndexMove<u32, ::core::result::Result<T, NotInSchema>> for Reader<'a, T>{
+    fn index_move(&self, index: u32) -> ::core::result::Result<T, NotInSchema> {
         self.get(index)
     }
 }
 
 impl <'a, T : FromU16> Reader<'a, T> {
-    pub fn get(&self, index: u32) -> ::std::result::Result<T, NotInSchema> {
+    pub fn get(&self, index: u32) -> ::core::result::Result<T, NotInSchema> {
         assert!(index < self.len());
         let result: u16 = PrimitiveElement::get(&self.reader, index);
         FromU16::from_u16(result)
@@ -119,7 +119,7 @@ impl <'a, T : FromU16> FromPointerBuilder<'a> for Builder<'a, T> {
 }
 
 impl <'a, T : ToU16 + FromU16>  Builder<'a, T> {
-    pub fn get(&self, index: u32) -> ::std::result::Result<T, NotInSchema> {
+    pub fn get(&self, index: u32) -> ::core::result::Result<T, NotInSchema> {
         assert!(index < self.len());
         let result: u16 = PrimitiveElement::get_from_builder(&self.builder, index);
         FromU16::from_u16(result)
@@ -138,8 +138,8 @@ impl <'a, T> crate::traits::SetPointerBuilder<Builder<'a, T>> for Reader<'a, T>
     }
 }
 
-impl <'a, T: FromU16> ::std::iter::IntoIterator for Reader<'a, T> {
-    type Item = ::std::result::Result<T, NotInSchema>;
+impl <'a, T: FromU16> ::core::iter::IntoIterator for Reader<'a, T> {
+    type Item = ::core::result::Result<T, NotInSchema>;
     type IntoIter = ListIter<Reader<'a, T>, Self::Item>;
 
     fn into_iter(self) -> Self::IntoIter {

capnp/src/io.rs

@@ -0,0 +1,115 @@
+//! Custom I/O traits that roughly mirror `std::io::{Read, BufRead, Write}`.
+//! This extra layer of indirection enables support of no-std environments.
+
+use crate::Result;
+
+pub trait Read {
+    fn read_exact(&mut self, buf: &mut [u8]) -> Result<()>;
+}
+
+pub trait BufRead : Read {
+    fn fill_buf(&mut self) -> Result<&[u8]>;
+    fn consume(&mut self, amt: usize);
+}
+
+pub trait Write {
+    fn write_all(&mut self, buf: &[u8]) -> Result<()>;
+}
+
+#[cfg(feature="std")]
+mod std_impls {
+    use crate::{Result};
+    use crate::io::{Read, BufRead, Write};
+
+    impl <R> Read for R where R: std::io::Read {
+        fn read_exact(&mut self, buf: &mut [u8]) -> Result<()> {
+            std::io::Read::read_exact(self, buf)?;
+            Ok(())
+        }
+    }
+
+    impl <R> BufRead for R where R: std::io::BufRead {
+        fn fill_buf(&mut self) -> Result<&[u8]> {
+            Ok(std::io::BufRead::fill_buf(self)?)
+        }
+        fn consume(&mut self, amt: usize) {
+            std::io::BufRead::consume(self, amt)
+        }
+    }
+
+    impl <W> Write for W where W: std::io::Write {
+        fn write_all(&mut self, buf: &[u8]) -> Result<()> {
+            std::io::Write::write_all(self, buf)?;
+            Ok(())
+        }
+    }
+}
+
+#[cfg(not(feature="std"))]
+mod no_std_impls {
+    use alloc::string::ToString;
+    use crate::{Error, Result};
+    use crate::io::{Read, BufRead, Write};
+
+    impl <'a> Write for &'a mut [u8] {
+        fn write_all(&mut self, buf: &[u8]) -> Result<()> {
+            if buf.len() > self.len() {
+                return Err(Error::failed("buffer is not large enough".to_string()));
+            }
+            let amt = buf.len();
+            let (a, b) = core::mem::replace(self, &mut []).split_at_mut(amt);
+            a.copy_from_slice(buf);
+            *self = b;
+            Ok(())
+        }
+    }
+
+    impl Write for alloc::vec::Vec<u8> {
+        fn write_all(&mut self, buf: &[u8]) -> Result<()> {
+            self.extend_from_slice(buf);
+            Ok(())
+        }
+    }
+
+    impl <W: ?Sized> Write for &mut W where W: Write {
+        fn write_all(&mut self, buf: &[u8]) -> Result<()> {
+            (**self).write_all(buf)
+        }
+    }
+
+    impl <'a> Read for &'a [u8] {
+        fn read_exact(&mut self, buf: &mut [u8]) -> Result<()> {
+            if buf.len() > self.len() {
+                return Err(Error::failed("buffer is not large enough".to_string()));
+            }
+            let (a, b) = self.split_at(buf.len());
+            buf.copy_from_slice(a);
+            *self = b;
+            Ok(())
+        }
+    }
+
+    impl <R: ?Sized> Read for &mut R where R: Read {
+        fn read_exact(&mut self, buf: &mut [u8]) -> Result<()> {
+            (**self).read_exact(buf)
+        }
+    }
+
+    impl <'a> BufRead for &'a [u8] {
+        fn fill_buf(&mut self) -> Result<&[u8]> {
+            Ok(*self)
+        }
+        fn consume(&mut self, amt: usize) {
+            *self = &self[amt..]
+        }
+    }
+
+    impl <R: ?Sized> BufRead for &mut R where R: BufRead {
+        fn fill_buf(&mut self) -> Result<&[u8]> {
+            (**self).fill_buf()
+        }
+        fn consume(&mut self, amt: usize) {
+            (**self).consume(amt)
+        }
+    }
+}