Use cfg-if to simplify lib.rs (#55)

Cargo.toml

@@ -19,6 +19,7 @@ members = ["tests/wasm_bindgen"]
 
 [dependencies]
 log = { version = "0.4", optional = true }
+cfg-if = "0.1"
 
 [target.'cfg(any(unix, target_os = "redox", target_os = "wasi"))'.dependencies]
 libc = "0.2.54"

src/error.rs

@@ -38,7 +38,7 @@ impl Error {
     }
 
     pub(crate) fn msg(&self) -> Option<&'static str> {
-        if let Some(msg) = super::error_msg_inner(self.0) {
+        if let Some(msg) = crate::imp::error_msg_inner(self.0) {
             Some(msg)
         } else {
             match *self {

src/ios.rs

@@ -11,7 +11,6 @@ extern crate std;
 
 use crate::Error;
 use core::num::NonZeroU32;
-use std::io;
 
 // TODO: Make extern once extern_types feature is stabilized. See:
 //   https://github.com/rust-lang/rust/issues/43467
@@ -29,7 +28,7 @@ pub fn getrandom_inner(dest: &mut [u8]) -> Result<(), Error> {
     let ret = unsafe { SecRandomCopyBytes(kSecRandomDefault, dest.len(), dest.as_mut_ptr()) };
     if ret == -1 {
         error!("SecRandomCopyBytes call failed");
-        Err(io::Error::last_os_error().into())
+        Err(Error::UNKNOWN)
     } else {
         Ok(())
     }

src/lib.rs

@@ -127,17 +127,23 @@
 #![no_std]
 #![cfg_attr(feature = "stdweb", recursion_limit = "128")]
 
-#[cfg(feature = "log")]
 #[macro_use]
-extern crate log;
-#[cfg(not(feature = "log"))]
-#[allow(unused)]
-macro_rules! error {
-    ($($x:tt)*) => {};
+extern crate cfg_if;
+
+cfg_if! {
+    if #[cfg(feature = "log")] {
+        #[allow(unused)]
+        #[macro_use]
+        extern crate log;
+    } else {
+        #[allow(unused)]
+        macro_rules! error {
+            ($($x:tt)*) => {};
+        }
+    }
 }
 
-// temp fix for stdweb
-#[cfg(target_arch = "wasm32")]
+#[cfg(feature = "std")]
 extern crate std;
 
 mod error;
@@ -149,27 +155,8 @@ mod util;
 #[allow(dead_code)]
 mod util_libc;
 
-// System-specific implementations.
-//
-// These should all provide getrandom_inner with the same signature as getrandom.
-
-macro_rules! mod_use {
-    ($cond:meta, $module:ident) => {
-        #[$cond]
-        mod $module;
-        #[$cond]
-        use crate::$module::{error_msg_inner, getrandom_inner};
-    };
-}
-
-// These targets use std anyway, so we use the std declarations.
-#[cfg(any(
-    feature = "std",
-    windows,
-    unix,
-    target_os = "redox",
-    target_arch = "wasm32",
-))]
+// std-only trait definitions (also need for use_file)
+#[cfg(any(feature = "std", unix, target_os = "redox"))]
 mod error_impls;
 
 // These targets read from a file as a fallback method.
@@ -180,79 +167,69 @@ mod error_impls;
     target_os = "solaris",
     target_os = "illumos",
 ))]
+#[allow(dead_code)]
 mod use_file;
 
-mod_use!(cfg(target_os = "android"), linux_android);
-mod_use!(cfg(target_os = "bitrig"), openbsd_bitrig);
-mod_use!(cfg(target_os = "cloudabi"), cloudabi);
-mod_use!(cfg(target_os = "dragonfly"), use_file);
-mod_use!(cfg(target_os = "emscripten"), use_file);
-mod_use!(cfg(target_os = "freebsd"), freebsd);
-mod_use!(cfg(target_os = "fuchsia"), fuchsia);
-mod_use!(cfg(target_os = "haiku"), use_file);
-mod_use!(cfg(target_os = "illumos"), solaris_illumos);
-mod_use!(cfg(target_os = "ios"), ios);
-mod_use!(cfg(target_os = "linux"), linux_android);
-mod_use!(cfg(target_os = "macos"), macos);
-mod_use!(cfg(target_os = "netbsd"), use_file);
-mod_use!(cfg(target_os = "openbsd"), openbsd_bitrig);
-mod_use!(cfg(target_os = "redox"), use_file);
-mod_use!(cfg(target_os = "solaris"), solaris_illumos);
-mod_use!(cfg(windows), windows);
-mod_use!(cfg(target_env = "sgx"), rdrand);
-mod_use!(cfg(all(target_arch = "x86_64", target_os = "uefi")), rdrand);
-mod_use!(cfg(target_os = "wasi"), wasi);
-
-mod_use!(
-    cfg(all(
-        target_arch = "wasm32",
-        not(target_os = "emscripten"),
-        not(target_os = "wasi"),
-        feature = "wasm-bindgen"
-    )),
-    wasm32_bindgen
-);
-
-mod_use!(
-    cfg(all(
-        target_arch = "wasm32",
-        not(target_os = "emscripten"),
-        not(target_os = "wasi"),
-        not(feature = "wasm-bindgen"),
-        feature = "stdweb",
-    )),
-    wasm32_stdweb
-);
-
-mod_use!(
-    cfg(not(any(
-        target_os = "android",
-        target_os = "bitrig",
-        target_os = "cloudabi",
-        target_os = "dragonfly",
-        target_os = "emscripten",
-        target_os = "freebsd",
-        target_os = "fuchsia",
-        target_os = "haiku",
-        target_os = "illumos",
-        target_os = "ios",
-        target_os = "linux",
-        target_os = "macos",
-        target_os = "netbsd",
-        target_os = "openbsd",
-        target_os = "redox",
-        target_os = "solaris",
-        all(target_arch = "x86_64", target_os = "uefi"),
-        target_os = "wasi",
-        target_env = "sgx",
-        windows,
-        all(
-            target_arch = "wasm32",
-            any(feature = "wasm-bindgen", feature = "stdweb"),
-        ),
-    ))),
-    dummy
-);
+// System-specific implementations.
+//
+// These should all provide getrandom_inner with the same signature as getrandom.
+cfg_if! {
+    if #[cfg(target_os = "android")] {
+        #[path = "linux_android.rs"] mod imp;
+    } else if #[cfg(target_os = "bitrig")] {
+        #[path = "openbsd_bitrig.rs"] mod imp;
+    } else if #[cfg(target_os = "cloudabi")] {
+        #[path = "cloudabi.rs"] mod imp;
+    } else if #[cfg(target_os = "dragonfly")] {
+        #[path = "use_file.rs"] mod imp;
+    } else if #[cfg(target_os = "emscripten")] {
+        #[path = "use_file.rs"] mod imp;
+    } else if #[cfg(target_os = "freebsd")] {
+        #[path = "freebsd.rs"] mod imp;
+    } else if #[cfg(target_os = "fuchsia")] {
+        #[path = "fuchsia.rs"] mod imp;
+    } else if #[cfg(target_os = "haiku")] {
+        #[path = "use_file.rs"] mod imp;
+    } else if #[cfg(target_os = "illumos")] {
+        #[path = "solaris_illumos.rs"] mod imp;
+    } else if #[cfg(target_os = "ios")] {
+        #[path = "ios.rs"] mod imp;
+    } else if #[cfg(target_os = "linux")] {
+        #[path = "linux_android.rs"] mod imp;
+    } else if #[cfg(target_os = "macos")] {
+        #[path = "macos.rs"] mod imp;
+    } else if #[cfg(target_os = "netbsd")] {
+        #[path = "use_file.rs"] mod imp;
+    } else if #[cfg(target_os = "openbsd")] {
+        #[path = "openbsd_bitrig.rs"] mod imp;
+    } else if #[cfg(target_os = "redox")] {
+        #[path = "use_file.rs"] mod imp;
+    } else if #[cfg(target_os = "solaris")] {
+        #[path = "solaris_illumos.rs"] mod imp;
+    } else if #[cfg(target_os = "wasi")] {
+        #[path = "wasi.rs"] mod imp;
+    } else if #[cfg(windows)] {
+        #[path = "windows.rs"] mod imp;
+    } else if #[cfg(target_env = "sgx")] {
+        #[path = "rdrand.rs"] mod imp;
+    } else if #[cfg(all(target_arch = "x86_64", target_os = "uefi"))] {
+        #[path = "rdrand.rs"] mod imp;
+    } else if #[cfg(target_arch = "wasm32")] {
+        cfg_if! {
+            if #[cfg(feature = "wasm-bindgen")] {
+                #[path = "wasm32_bindgen.rs"] mod imp;
+            } else if #[cfg(feature = "stdweb")] {
+                // temp fix for stdweb
+                extern crate std;
+                #[path = "wasm32_stdweb.rs"] mod imp;
+            } else {
+                #[path = "dummy.rs"] mod imp;
+            }
+        }
+    } else {
+        #[path = "dummy.rs"] mod imp;
+    }
+}
 
 /// Fill `dest` with random bytes from the system's preferred random number
 /// source.
@@ -266,5 +243,5 @@ mod_use!(
 /// significantly slower than a user-space CSPRNG; for the latter consider
 /// [`rand::thread_rng`](https://docs.rs/rand/*/rand/fn.thread_rng.html).
 pub fn getrandom(dest: &mut [u8]) -> Result<(), error::Error> {
-    getrandom_inner(dest)
+    imp::getrandom_inner(dest)
 }

src/rdrand.rs

@@ -7,6 +7,7 @@
 // except according to those terms.
 
 //! Implementation for SGX using RDRAND instruction
+#[cfg(not(target_feature = "rdrand"))]
 use crate::util::LazyBool;
 use crate::Error;
 use core::arch::x86_64::_rdrand64_step;

src/wasi.rs

@@ -9,16 +9,15 @@
 //! Implementation for WASI
 use crate::Error;
 use core::num::NonZeroU32;
-use std::io;
 
 pub fn getrandom_inner(dest: &mut [u8]) -> Result<(), Error> {
     let ret =
         unsafe { libc::__wasi_random_get(dest.as_mut_ptr() as *mut libc::c_void, dest.len()) };
-    if ret == libc::__WASI_ESUCCESS {
-        Ok(())
+    if let Some(code) = NonZeroU32::new(ret as u32) {
+        error!("WASI: __wasi_random_get failed with return value {}", code);
+        Err(Error::from(code))
     } else {
-        error!("WASI: __wasi_random_get failed with return value {}", ret);
-        Err(io::Error::last_os_error().into())
+        Ok(()) // Zero means success for WASI
     }
 }
 

src/wasm32_bindgen.rs

@@ -7,6 +7,8 @@
 // except according to those terms.
 
 //! Implementation for WASM via wasm-bindgen
+extern crate std;
+
 use core::cell::RefCell;
 use core::mem;
 use core::num::NonZeroU32;

src/windows.rs

@@ -11,7 +11,6 @@ extern crate std;
 
 use crate::Error;
 use core::num::NonZeroU32;
-use std::io;
 
 extern "system" {
     #[link_name = "SystemFunction036"]
@@ -24,7 +23,7 @@ pub fn getrandom_inner(dest: &mut [u8]) -> Result<(), Error> {
         let ret = unsafe { RtlGenRandom(chunk.as_mut_ptr(), chunk.len() as u32) };
         if ret == 0 {
             error!("RtlGenRandom call failed");
-            return Err(io::Error::last_os_error().into());
+            return Err(Error::UNKNOWN);
         }
     }
     Ok(())