Add shims for modules that we can't implement on CloudABI.

As discussed in #47268, libstd isn't ready to have certain functionality
disabled yet. Follow wasm's approach of adding no-op modules for all of
the features that we can't implement.

I've placed all of those shims in a shims/ subdirectory, so we (the
CloudABI folks) can experiment with removing them more easily. It also
ensures that the code that does work doesn't get polluted with lots of
useless boilerplate code.

1 files changed, 95 insertions, 0 deletions

diff --git a/src/libstd/sys/cloudabi/shims/os.rs b/src/libstd/sys/cloudabi/shims/os.rs
new file mode 100644
index 00000000000..1e355d9ad04
--- /dev/null
+++ b/src/libstd/sys/cloudabi/shims/os.rs
@@ -0,0 +1,95 @@
+// Copyright 2018 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+use error::Error as StdError;
+use ffi::{OsStr, OsString};
+use fmt;
+use io;
+use iter;
+use path::{self, PathBuf};
+use sys::{unsupported, Void};
+
+pub fn getcwd() -> io::Result<PathBuf> {
+    unsupported()
+}
+
+pub fn chdir(_: &path::Path) -> io::Result<()> {
+    unsupported()
+}
+
+pub type Env = iter::Empty<(OsString, OsString)>;
+
+pub fn env() -> Env {
+    iter::empty()
+}
+
+pub fn getenv(_: &OsStr) -> io::Result<Option<OsString>> {
+    Ok(None)
+}
+
+pub fn setenv(_: &OsStr, _: &OsStr) -> io::Result<()> {
+    unsupported()
+}
+
+pub fn unsetenv(_: &OsStr) -> io::Result<()> {
+    unsupported()
+}
+
+pub struct SplitPaths<'a>(&'a Void);
+
+pub fn split_paths(_unparsed: &OsStr) -> SplitPaths {
+    panic!("unsupported")
+}
+
+impl<'a> Iterator for SplitPaths<'a> {
+    type Item = PathBuf;
+    fn next(&mut self) -> Option<PathBuf> {
+        match *self.0 {}
+    }
+}
+
+#[derive(Debug)]
+pub struct JoinPathsError;
+
+pub fn join_paths<I, T>(_paths: I) -> Result<OsString, JoinPathsError>
+where
+    I: Iterator<Item = T>,
+    T: AsRef<OsStr>,
+{
+    Err(JoinPathsError)
+}
+
+impl fmt::Display for JoinPathsError {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        "not supported on CloudABI yet".fmt(f)
+    }
+}
+
+impl StdError for JoinPathsError {
+    fn description(&self) -> &str {
+        "not supported on CloudABI yet"
+    }
+}
+
+pub fn home_dir() -> Option<PathBuf> {
+    None
+}
+
+pub fn temp_dir() -> PathBuf {
+    PathBuf::from("/tmp")
+}
+
+pub fn current_exe() -> io::Result<PathBuf> {
+    unsupported()
+}
+
+pub fn getpid() -> u32 {
+    1
+}