From 3a6e2c9c37fdc8cd06a314c399805daf968da6a8 Mon Sep 17 00:00:00 2001
From: Lachlan Sneff <lachlan.sneff@gmail.com>
Date: Tue, 2 Apr 2019 11:49:05 -0700
Subject: [PATCH] Change tagged and untagged methods

---
 lib/wasi/src/state.rs          | 11 +++--
 lib/wasi/src/syscalls/types.rs | 86 +++++++++++++++++++++++++---------
 2 files changed, 72 insertions(+), 25 deletions(-)

diff --git a/lib/wasi/src/state.rs b/lib/wasi/src/state.rs
index 2f7cb8ef5..6fda1b8a3 100644
--- a/lib/wasi/src/state.rs
+++ b/lib/wasi/src/state.rs
@@ -201,10 +201,13 @@ impl WasiFs {
         let inode_val = &self.inodes[fd.inode];
 
         if inode_val.is_preopened {
-            Ok(PrestatEnum::PreOpenDir {
-                pr_name_len: inode_val.name.len() as u32,
-            }
-            .get_untagged())
+            Ok(__wasi_prestat_t {
+                pr_type: __WASI_PREOPENTYPE_DIR,
+                u: PrestatEnum::Dir {
+                    pr_name_len: inode_val.name.len() as u32,
+                }
+                .untagged(),
+            })
         } else {
             Err(__WASI_EBADF)
         }
diff --git a/lib/wasi/src/syscalls/types.rs b/lib/wasi/src/syscalls/types.rs
index 157720675..b6f7bada2 100644
--- a/lib/wasi/src/syscalls/types.rs
+++ b/lib/wasi/src/syscalls/types.rs
@@ -134,6 +134,24 @@ pub union __wasi_event_u {
     fd_readwrite: __wasi_event_fd_readwrite_t,
 }
 
+#[derive(Copy, Clone)]
+pub enum EventEnum {
+    FdReadWrite {
+        nbytes: __wasi_filesize_t,
+        flags: __wasi_eventrwflags_t,
+    },
+}
+
+impl EventEnum {
+    pub fn untagged(self) -> __wasi_event_u {
+        match self {
+            EventEnum::FdReadWrite { nbytes, flags } => __wasi_event_u {
+                fd_readwrite: __wasi_event_fd_readwrite_t { nbytes, flags },
+            },
+        }
+    }
+}
+
 #[derive(Copy, Clone)]
 #[repr(C)]
 pub struct __wasi_event_t {
@@ -143,6 +161,18 @@ pub struct __wasi_event_t {
     pub u: __wasi_event_u,
 }
 
+impl __wasi_event_t {
+    pub fn tagged(&self) -> Option<EventEnum> {
+        match self.type_ {
+            __WASI_EVENTTYPE_FD_READ | __WASI_EVENTTYPE_FD_WRITE => Some(EventEnum::FdReadWrite {
+                nbytes: unsafe { self.u.fd_readwrite.nbytes },
+                flags: unsafe { self.u.fd_readwrite.flags },
+            }),
+            _ => None,
+        }
+    }
+}
+
 pub type __wasi_eventrwflags_t = u16;
 pub const __WASI_EVENT_FD_READWRITE_HANGUP: u16 = 1 << 0;
 
@@ -171,7 +201,7 @@ pub const __WASI_PREOPENTYPE_DIR: u8 = 0;
 #[derive(Debug, Copy, Clone, PartialEq, Eq)]
 #[repr(C)]
 pub struct __wasi_prestat_u_dir_t {
-    pr_name_len: u32,
+    pub pr_name_len: u32,
 }
 
 unsafe impl ValueType for __wasi_prestat_u_dir_t {}
@@ -187,37 +217,32 @@ unsafe impl ValueType for __wasi_prestat_u {}
 #[derive(Copy, Clone)]
 #[repr(C)]
 pub struct __wasi_prestat_t {
-    pr_type: __wasi_preopentype_t,
-    u: __wasi_prestat_u,
+    pub pr_type: __wasi_preopentype_t,
+    pub u: __wasi_prestat_u,
 }
 
 #[derive(Copy, Clone)]
 pub enum PrestatEnum {
-    PreOpenDir { pr_name_len: u32 },
+    Dir { pr_name_len: u32 },
 }
 
-impl __wasi_prestat_t {
-    pub fn get_tagged(&self) -> PrestatEnum {
-        match self.pr_type {
-            __WASI_PREOPENTYPE_DIR => PrestatEnum::PreOpenDir {
-                pr_name_len: unsafe { self.u.dir.pr_name_len },
+impl PrestatEnum {
+    pub fn untagged(self) -> __wasi_prestat_u {
+        match self {
+            PrestatEnum::Dir { pr_name_len } => __wasi_prestat_u {
+                dir: __wasi_prestat_u_dir_t { pr_name_len },
             },
-            _ => panic!("Invalid enum variant in __wasi_prestat_t: {}", self.pr_type),
         }
     }
 }
 
-impl PrestatEnum {
-    pub fn get_untagged(&self) -> __wasi_prestat_t {
-        match self {
-            PrestatEnum::PreOpenDir { pr_name_len } => __wasi_prestat_t {
-                pr_type: __WASI_PREOPENTYPE_DIR,
-                u: __wasi_prestat_u {
-                    dir: __wasi_prestat_u_dir_t {
-                        pr_name_len: *pr_name_len,
-                    },
-                },
-            },
+impl __wasi_prestat_t {
+    pub fn tagged(&self) -> Option<PrestatEnum> {
+        match self.pr_type {
+            __WASI_PREOPENTYPE_DIR => Some(PrestatEnum::Dir {
+                pr_name_len: unsafe { self.u.dir.pr_name_len },
+            }),
+            _ => None,
         }
     }
 }
@@ -398,6 +423,25 @@ pub struct __wasi_subscription_t {
     pub u: __wasi_subscription_u,
 }
 
+pub enum SubscriptionEnum {
+    Clock(__wasi_subscription_clock_t),
+    FdReadWrite(__wasi_subscription_fs_readwrite_t),
+}
+
+impl __wasi_subscription_t {
+    pub fn tagged(&self) -> Option<SubscriptionEnum> {
+        match self.type_ {
+            __WASI_EVENTTYPE_CLOCK => Some(SubscriptionEnum::Clock(unsafe { self.u.clock })),
+            __WASI_EVENTTYPE_FD_READ | __WASI_EVENTTYPE_FD_WRITE => {
+                Some(SubscriptionEnum::FdReadWrite(unsafe {
+                    self.u.fd_readwrite
+                }))
+            }
+            _ => None,
+        }
+    }
+}
+
 pub type __wasi_timestamp_t = u64;
 
 pub type __wasi_userdata_t = u64;