Emscripten tests compiling again

lib/emscripten/src/file_descriptor.rs

@@ -0,0 +1,25 @@
+use std::io;
+use std::io::Error;
+use std::io::ErrorKind;
+use std::io::Read;
+
+pub struct FileDescriptor(libc::c_int);
+
+impl FileDescriptor {
+    pub fn new(file_descriptor_number: libc::c_int) -> FileDescriptor {
+        FileDescriptor(file_descriptor_number)
+    }
+}
+
+impl Read for FileDescriptor {
+    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
+        let file_descriptor: libc::c_int = self.0;
+        let count =
+            unsafe { libc::read(file_descriptor, buf.as_mut_ptr() as *mut libc::c_void, 1) };
+        if count < 0 {
+            Err(Error::new(ErrorKind::Other, "read error"))
+        } else {
+            Ok(count as usize)
+        }
+    }
+}

lib/emscripten/src/lib.rs

@@ -4,21 +4,26 @@ extern crate wasmer_runtime;
 #[macro_use]
 use wasmer_runtime::macros;
 
-use wasmer_runtime::{
-    import::{Imports, NamespaceMap},
-    export::{Export, Context, GlobalPointer, FuncPointer},
-    types::{
-        FuncSig, Type::{self, *}, Value,
-        GlobalDesc,
-    },
-    vm::{self, LocalGlobal, Func},
-    memory::LinearMemory,
-};
 use byteorder::{ByteOrder, LittleEndian};
+use hashbrown::{hash_map::Entry, HashMap};
 use libc::c_int;
 use std::cell::UnsafeCell;
 use std::mem;
-use hashbrown::{hash_map::Entry, HashMap};
+use wasmer_runtime::{
+    export::{Context, Export, FuncPointer, GlobalPointer},
+    import::{Imports, NamespaceMap},
+    memory::LinearMemory,
+    types::{
+        FuncSig, GlobalDesc,
+        Type::{self, *},
+        Value,
+    },
+    vm::{self, Func, LocalGlobal},
+};
+
+//#[cfg(test)]
+mod file_descriptor;
+pub mod stdio;
 
 // EMSCRIPTEN APIS
 mod env;
@@ -124,7 +129,7 @@ macro_rules! global {
         unsafe {
             GlobalPointer::new(
                 // NOTE: Taking a shortcut here. LocalGlobal is a struct containing just u64.
-                std::mem::transmute::<&u64, *mut LocalGlobal>($value)
+                std::mem::transmute::<&u64, *mut LocalGlobal>($value),
             )
         }
     }};
@@ -134,7 +139,7 @@ pub struct EmscriptenGlobals<'a> {
     pub data: HashMap<&'a str, HashMap<&'a str, (u64, Type)>>, // <namespace, <field_name, (global_value, type)>>
 }
 
-impl <'a> EmscriptenGlobals<'a> {
+impl<'a> EmscriptenGlobals<'a> {
     pub fn new() -> Self {
         let mut data = HashMap::new();
         let mut env_namepace = HashMap::new();
@@ -150,9 +155,7 @@ impl <'a> EmscriptenGlobals<'a> {
         data.insert("env", env_namepace);
         data.insert("global", global_namepace);
 
-        Self {
-            data,
-        }
+        Self { data }
     }
 }
 
@@ -175,7 +178,7 @@ pub fn generate_emscripten_env(globals: &EmscriptenGlobals) -> Imports {
             global: GlobalDesc {
                 mutable: false,
                 ty: ty.clone(),
-            }
+            },
         },
     );
 
@@ -187,7 +190,7 @@ pub fn generate_emscripten_env(globals: &EmscriptenGlobals) -> Imports {
             global: GlobalDesc {
                 mutable: false,
                 ty: ty.clone(),
-            }
+            },
         },
     );
 
@@ -199,7 +202,7 @@ pub fn generate_emscripten_env(globals: &EmscriptenGlobals) -> Imports {
             global: GlobalDesc {
                 mutable: false,
                 ty: ty.clone(),
-            }
+            },
         },
     );
 
@@ -211,7 +214,7 @@ pub fn generate_emscripten_env(globals: &EmscriptenGlobals) -> Imports {
             global: GlobalDesc {
                 mutable: false,
                 ty: ty.clone(),
-            }
+            },
         },
     );
 
@@ -223,7 +226,7 @@ pub fn generate_emscripten_env(globals: &EmscriptenGlobals) -> Imports {
             global: GlobalDesc {
                 mutable: false,
                 ty: ty.clone(),
-            }
+            },
         },
     );
 
@@ -235,7 +238,7 @@ pub fn generate_emscripten_env(globals: &EmscriptenGlobals) -> Imports {
             global: GlobalDesc {
                 mutable: false,
                 ty: ty.clone(),
-            }
+            },
         },
     );
 
@@ -252,7 +255,6 @@ pub fn generate_emscripten_env(globals: &EmscriptenGlobals) -> Imports {
         },
     );
 
-
     env_namespace.insert(
         "putchar",
         Export::Function {

lib/emscripten/src/stdio.rs

@@ -0,0 +1,75 @@
+use super::file_descriptor::FileDescriptor;
+use libc;
+use std::io::BufReader;
+use std::io::Read;
+
+// A struct to hold the references to the base stdout and the captured one
+pub struct StdioCapturer {
+    stdout_backup: libc::c_int,
+    stderr_backup: libc::c_int,
+    stdout_reader: libc::c_int,
+    stderr_reader: libc::c_int,
+}
+
+// Implementation inspired in
+// https://github.com/rust-lang/rust/blob/7d52cbce6db83e4fc2d8706b4e4b9c7da76cbcf8/src/test/run-pass/issues/issue-30490.rs
+// Currently only works in Unix systems (Mac, Linux)
+impl StdioCapturer {
+    fn pipe() -> (libc::c_int, libc::c_int) {
+        let mut fds = [0; 2];
+
+        #[cfg(not(target_os = "windows"))]
+        assert_eq!(unsafe { libc::pipe(fds.as_mut_ptr()) }, 0);
+        #[cfg(target_os = "windows")]
+        assert_eq!(
+            unsafe { libc::pipe(fds.as_mut_ptr(), 1000, libc::O_TEXT) },
+            0
+        );
+
+        (fds[0], fds[1])
+    }
+
+    pub fn new() -> Self {
+        let stdout_backup = unsafe { libc::dup(libc::STDOUT_FILENO) };
+        let stderr_backup = unsafe { libc::dup(libc::STDERR_FILENO) };
+
+        let (stdout_reader, stdout_writer) = Self::pipe();
+        let (stderr_reader, stderr_writer) = Self::pipe();
+
+        assert!(unsafe { libc::dup2(stdout_writer, libc::STDOUT_FILENO) } > -1);
+        assert!(unsafe { libc::dup2(stderr_writer, libc::STDERR_FILENO) } > -1);
+
+        // Make sure we close any duplicates of the writer end of the pipe,
+        // otherwise we can get stuck reading from the pipe which has open
+        // writers but no one supplying any input
+        assert_eq!(unsafe { libc::close(stdout_writer) }, 0);
+        assert_eq!(unsafe { libc::close(stderr_writer) }, 0);
+
+        StdioCapturer {
+            stdout_backup,
+            stderr_backup,
+            stdout_reader,
+            stderr_reader,
+        }
+    }
+
+    pub fn end(self) -> Result<(String, String), std::io::Error> {
+        // The Stdio passed into the Command took over (and closed) std{out, err}
+        // so we should restore them as they were.
+
+        assert!(unsafe { libc::dup2(self.stdout_backup, libc::STDOUT_FILENO) } > -1);
+        assert!(unsafe { libc::dup2(self.stderr_backup, libc::STDERR_FILENO) } > -1);
+
+        let fd = FileDescriptor::new(self.stdout_reader);
+        let mut reader = BufReader::new(fd);
+        let mut stdout_read = "".to_string();
+        let _ = reader.read_to_string(&mut stdout_read)?;
+
+        let fd = FileDescriptor::new(self.stderr_reader);
+        let mut reader = BufReader::new(fd);
+        let mut stderr_read = "".to_string();
+        let _ = reader.read_to_string(&mut stderr_read)?;
+
+        Ok((stdout_read, stderr_read))
+    }
+}