diff --git a/core/os/os2/errors_windows.odin b/core/os/os2/errors_windows.odin index 56acd503f..404560f98 100644 --- a/core/os/os2/errors_windows.odin +++ b/core/os/os2/errors_windows.odin @@ -55,13 +55,15 @@ _get_platform_error :: proc() -> Error { case win32.ERROR_NEGATIVE_SEEK: return .Invalid_Offset + case win32.ERROR_BROKEN_PIPE: + return .Broken_Pipe + case win32.ERROR_BAD_ARGUMENTS, win32.ERROR_INVALID_PARAMETER, win32.ERROR_NOT_ENOUGH_MEMORY, win32.ERROR_NO_MORE_FILES, win32.ERROR_LOCK_VIOLATION, - win32.ERROR_BROKEN_PIPE, win32.ERROR_CALL_NOT_IMPLEMENTED, win32.ERROR_INSUFFICIENT_BUFFER, win32.ERROR_INVALID_NAME, diff --git a/core/os/os2/pipe.odin b/core/os/os2/pipe.odin index 9254d6f8e..5d3e8368e 100644 --- a/core/os/os2/pipe.odin +++ b/core/os/os2/pipe.odin @@ -1,6 +1,43 @@ package os2 +/* +Create an anonymous pipe. + +This procedure creates an anonymous pipe, returning two ends of the pipe, `r` +and `w`. The file `r` is the readable end of the pipe. The file `w` is a +writeable end of the pipe. + +Pipes are used as an inter-process communication mechanism, to communicate +between a parent and a child process. The child uses one end of the pipe to +write data, and the parent uses the other end to read from the pipe +(or vice-versa). When a parent passes one of the ends of the pipe to the child +process, that end of the pipe needs to be closed by the parent, before any data +is attempted to be read. + +Although pipes look like files and is compatible with most file APIs in package +os2, the way it's meant to be read is different. Due to asynchronous nature of +the communication channel, the data may not be present at the time of a read +request. The other scenario is when a pipe has no data because the other end +of the pipe was closed by the child process. +*/ @(require_results) pipe :: proc() -> (r, w: ^File, err: Error) { return _pipe() } + +/* +Check if the pipe has any data. + +This procedure checks whether a read-end of the pipe has data that can be +read, and returns `true`, if the pipe has readable data, and `false` if the +pipe is empty. This procedure does not block the execution of the current +thread. + +**Note**: If the other end of the pipe was closed by the child process, the +`.Broken_Pipe` +can be returned by this procedure. Handle these errors accordingly. +*/ +@(require_results) +pipe_has_data :: proc(r: ^File) -> (ok: bool, err: Error) { + return _pipe_has_data(r) +} diff --git a/core/os/os2/pipe_linux.odin b/core/os/os2/pipe_linux.odin index ac3382bc3..852674c69 100644 --- a/core/os/os2/pipe_linux.odin +++ b/core/os/os2/pipe_linux.odin @@ -15,3 +15,29 @@ _pipe :: proc() -> (r, w: ^File, err: Error) { return } + +@(require_results) +_pipe_has_data :: proc(r: ^File) -> (ok: bool, err: Error) { + if r == nil || r.impl == nil { + return false, nil + } + fd := linux.Fd((^File_Impl)(r.impl).fd) + poll_fds := []linux.Poll_Fd { + linux.Poll_Fd { + fd = fd, + events = {.IN, .HUP}, + }, + } + n, errno := linux.poll(poll_fds, 0) + if n != 1 || errno != nil { + return false, _get_platform_error(errno) + } + pipe_events := poll_fds[0].revents + if pipe_events >= {.IN} { + return true, nil + } + if pipe_events >= {.HUP} { + return false, .Broken_Pipe + } + return false, nil +} \ No newline at end of file diff --git a/core/os/os2/pipe_posix.odin b/core/os/os2/pipe_posix.odin index 487e32aea..463f29f01 100644 --- a/core/os/os2/pipe_posix.odin +++ b/core/os/os2/pipe_posix.odin @@ -44,3 +44,28 @@ _pipe :: proc() -> (r, w: ^File, err: Error) { return } +@(require_results) +_pipe_has_data :: proc(r: ^File) -> (ok: bool, err: Error) { + if r == nil || r.impl == nil { + return false, nil + } + fd := posix.FD((^File_Impl)(r.impl).fd) + poll_fds := []posix.pollfd { + posix.pollfd { + fd = fd, + events = {.IN, .HUP}, + }, + } + n := posix.poll(raw_data(poll_fds), u32(len(poll_fds)), 0) + if n != 1 { + return false, _get_platform_error() + } + pipe_events := poll_fds[0].revents + if pipe_events >= {.IN} { + return true, nil + } + if pipe_events >= {.HUP} { + return false, .Broken_Pipe + } + return false, nil +} \ No newline at end of file diff --git a/core/os/os2/pipe_windows.odin b/core/os/os2/pipe_windows.odin index ee93fb683..5a6048f06 100644 --- a/core/os/os2/pipe_windows.odin +++ b/core/os/os2/pipe_windows.odin @@ -15,3 +15,15 @@ _pipe :: proc() -> (r, w: ^File, err: Error) { return new_file(uintptr(p[0]), ""), new_file(uintptr(p[1]), ""), nil } +@(require_results) +_pipe_has_data :: proc(r: ^File) -> (ok: bool, err: Error) { + if r == nil || r.impl == nil { + return false, nil + } + handle := win32.HANDLE((^File_Impl)(r.impl).fd) + bytes_available: u32 + if !win32.PeekNamedPipe(handle, nil, 0, nil, &bytes_available, nil) { + return false, _get_platform_error() + } + return bytes_available > 0, nil +} \ No newline at end of file diff --git a/core/sys/windows/kernel32.odin b/core/sys/windows/kernel32.odin index 2771581e6..d9648ec45 100644 --- a/core/sys/windows/kernel32.odin +++ b/core/sys/windows/kernel32.odin @@ -381,6 +381,14 @@ foreign kernel32 { nDefaultTimeOut: DWORD, lpSecurityAttributes: LPSECURITY_ATTRIBUTES, ) -> HANDLE --- + PeekNamedPipe :: proc( + hNamedPipe: HANDLE, + lpBuffer: rawptr, + nBufferSize: u32, + lpBytesRead: ^u32, + lpTotalBytesAvail: ^u32, + lpBytesLeftThisMessage: ^u32, + ) -> BOOL --- CancelIo :: proc(handle: HANDLE) -> BOOL --- GetOverlappedResult :: proc( hFile: HANDLE,