Files
scryer-prolog/src/prolog/machine/streams.rs
2020-05-03 18:49:15 -06:00

611 lines
17 KiB
Rust

use crate::prolog_parser::ast::*;
use crate::prolog::read::readline::*;
use crate::prolog::machine::machine_errors::*;
use crate::prolog::machine::machine_indices::*;
use crate::prolog::machine::machine_state::*;
use crate::prolog::read::PrologStream;
use std::cell::RefCell;
use std::error::Error;
use std::fmt;
use std::fs::File;
use std::io::{stdout, Cursor, ErrorKind, Read, Write};
use std::hash::{Hash, Hasher};
use std::net::TcpStream;
use std::rc::Rc;
#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
pub enum StreamType {
Binary,
Text,
}
#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
pub enum EOFAction {
EOFCode,
Error,
Reset,
}
/* all these streams are closed automatically when the instance is
* dropped. */
pub enum StreamInstance {
Bytes(Cursor<Vec<u8>>),
DynReadSource(Box<dyn Read>),
File(File),
Null,
ReadlineStream(ReadlineStream),
// Stdin,
Stdout,
TcpStream(TcpStream),
}
impl fmt::Debug for StreamInstance {
fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
match self {
&StreamInstance::Bytes(ref bytes) =>
write!(fmt, "Bytes({:?})", bytes),
&StreamInstance::DynReadSource(_) =>
write!(fmt, "DynReadSource(_)"), // Hacky solution.
&StreamInstance::File(ref file) => write!(fmt, "File({:?})", file),
&StreamInstance::Null => write!(fmt, "Null"),
&StreamInstance::ReadlineStream(ref readline_stream) =>
write!(fmt, "ReadlineStream({:?})", readline_stream),
// &StreamInstance::Stdin => write!(fmt, "Stdin"),
&StreamInstance::Stdout => write!(fmt, "Stdout"),
&StreamInstance::TcpStream(ref tcp_stream) =>
write!(fmt, "TcpStream({:?})", tcp_stream),
}
}
}
#[derive(Debug, Clone)]
struct WrappedStreamInstance(Rc<RefCell<StreamInstance>>);
impl WrappedStreamInstance {
#[inline]
fn new(stream_inst: StreamInstance) -> Self {
WrappedStreamInstance(Rc::new(RefCell::new(stream_inst)))
}
}
impl PartialEq for WrappedStreamInstance {
#[inline]
fn eq(&self, other: &Self) -> bool {
Rc::ptr_eq(&self.0, &other.0)
}
}
impl Eq for WrappedStreamInstance {}
impl Hash for WrappedStreamInstance {
fn hash<H: Hasher>(&self, state: &mut H) {
let rc = &self.0;
let ptr = Rc::into_raw(rc.clone());
state.write_usize(ptr as usize);
unsafe {
// necessary to avoid memory leak.
let _ = Rc::from_raw(ptr);
};
}
}
#[derive(Debug)]
enum StreamError {
ReadFromOutputStream,
WriteToInputStream,
FlushToInputStream,
}
impl fmt::Display for StreamError {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
match self {
StreamError::ReadFromOutputStream => {
write!(f, "attempted to read from a write-only stream")
}
StreamError::WriteToInputStream => {
write!(f, "attempted to write to a read-only stream")
}
StreamError::FlushToInputStream => {
write!(f, "attempted to flush a read-only stream")
}
}
}
}
impl Error for StreamError {}
#[derive(Debug, Clone, PartialEq, Eq, Hash)]
pub struct StreamOptions {
pub stream_type: StreamType,
pub reposition: bool,
pub alias: Option<ClauseName>,
pub eof_action: EOFAction,
}
impl Default for StreamOptions {
#[inline]
fn default() -> Self {
StreamOptions {
stream_type: StreamType::Text,
reposition: false,
alias: None,
eof_action: EOFAction::EOFCode,
}
}
}
#[derive(Debug, Clone, PartialEq, Eq, Hash)]
pub struct Stream {
pub options: StreamOptions,
stream_inst: WrappedStreamInstance,
}
impl From<TcpStream> for Stream {
fn from(tcp_stream: TcpStream) -> Self {
Stream {
options: StreamOptions::default(),
stream_inst: WrappedStreamInstance::new(
StreamInstance::TcpStream(tcp_stream)
)
}
}
}
impl From<String> for Stream {
fn from(string: String) -> Self {
Stream {
options: StreamOptions::default(),
stream_inst: WrappedStreamInstance::new(
StreamInstance::Bytes(Cursor::new(string.into_bytes()))
)
}
}
}
impl From<ReadlineStream> for Stream {
fn from(rl_stream: ReadlineStream) -> Self {
Stream {
options: StreamOptions::default(),
stream_inst: WrappedStreamInstance::new(
StreamInstance::ReadlineStream(rl_stream)
),
}
}
}
impl From<&'static str> for Stream {
fn from(src: &'static str) -> Stream {
Stream {
options: StreamOptions::default(),
stream_inst: WrappedStreamInstance::new(
StreamInstance::DynReadSource(Box::new(src.as_bytes()))
),
}
}
}
impl From<File> for Stream {
fn from(file: File) -> Stream {
Stream {
options: StreamOptions::default(),
stream_inst: WrappedStreamInstance::new(
StreamInstance::File(file)
),
}
}
}
impl Stream {
#[inline]
pub(crate)
fn as_ptr(&self) -> *const u8 {
let rc = self.stream_inst.0.clone();
let ptr = Rc::into_raw(rc);
unsafe {
// must be done to avoid memory leak.
let _ = Rc::from_raw(ptr);
}
ptr as *const u8
}
#[inline]
pub(crate)
fn stdout() -> Self {
Stream {
options: StreamOptions::default(),
stream_inst: WrappedStreamInstance::new(
StreamInstance::Stdout
),
}
}
/*
#[inline]
pub(crate)
fn stdin() -> Self {
Stream {
options: StreamOptions::default(),
stream_inst: WrappedStreamInstance::new(
StreamInstance::Stdin
),
}
}
*/
#[inline]
pub(crate)
fn null_stream() -> Self {
Stream {
options: StreamOptions::default(), // TODO: null_options?
stream_inst: WrappedStreamInstance::new(
StreamInstance::Null
),
}
}
#[inline]
pub(crate)
fn is_stdout(&self) -> bool {
match *self.stream_inst.0.borrow() {
StreamInstance::Stdout => {
true
}
_ => {
false
}
}
}
#[inline]
pub(crate)
fn is_stdin(&self) -> bool {
match *self.stream_inst.0.borrow() {
//StreamInstance::Stdin |
StreamInstance::ReadlineStream(_) => {
true
}
_ => {
false
}
}
}
#[inline]
pub(crate)
fn is_input_stream(&self) -> bool {
match *self.stream_inst.0.borrow() {
// StreamInstance::Stdin |
StreamInstance::TcpStream(_) |
StreamInstance::Bytes(_) |
StreamInstance::ReadlineStream(_) |
StreamInstance::DynReadSource(_) |
StreamInstance::File(_) => {
true
}
_ => {
false
}
}
}
#[inline]
pub(crate)
fn is_output_stream(&self) -> bool {
match *self.stream_inst.0.borrow() {
StreamInstance::Stdout
| StreamInstance::TcpStream(_)
| StreamInstance::Bytes(_)
| StreamInstance::File(_) => {
true
}
_ => {
false
}
}
}
}
impl MachineState {
pub(crate)
fn to_stream_options(
&self,
alias: Addr,
eof_action: Addr,
reposition: Addr,
stream_type: Addr,
) -> StreamOptions {
let alias =
match self.store(self.deref(alias)) {
Addr::Con(h) if self.heap.atom_at(h) => {
if let HeapCellValue::Atom(ref name, _) = &self.heap[h] {
Some(name.clone())
} else {
unreachable!()
}
}
_ => {
None
}
};
let eof_action =
match self.store(self.deref(eof_action)) {
Addr::Con(h) if self.heap.atom_at(h) => {
if let HeapCellValue::Atom(ref name, _) = &self.heap[h] {
match name.as_str() {
"eof_code" => EOFAction::EOFCode,
"error" => EOFAction::Error,
"reset" => EOFAction::Reset,
_ => unreachable!(),
}
} else {
unreachable!()
}
}
_ => {
unreachable!()
}
};
let reposition =
match self.store(self.deref(reposition)) {
Addr::Con(h) if self.heap.atom_at(h) => {
if let HeapCellValue::Atom(ref name, _) = &self.heap[h] {
name.as_str() == "true"
} else {
unreachable!()
}
}
_ => {
unreachable!()
}
};
let stream_type =
match self.store(self.deref(stream_type)) {
Addr::Con(h) if self.heap.atom_at(h) => {
if let HeapCellValue::Atom(ref name, _) = &self.heap[h] {
match name.as_str() {
"text" => StreamType::Text,
"binary" => StreamType::Binary,
_ => unreachable!()
}
} else {
unreachable!()
}
}
_ => {
unreachable!()
}
};
let mut options = StreamOptions::default();
options.stream_type = stream_type;
options.reposition = reposition;
options.alias = alias;
options.eof_action = eof_action;
options
}
pub(crate)
fn get_stream_or_alias(
&mut self,
addr: Addr,
indices: &IndexStore,
caller: &'static str,
arity: usize,
) -> Result<Stream, MachineStub>
{
Ok(match addr {
Addr::Con(h) if self.heap.atom_at(h) => {
if let HeapCellValue::Atom(ref atom, ref spec) = self.heap.clone(h) {
match indices.stream_aliases.get(atom) {
Some(stream) => {
stream.clone()
}
None => {
let stub = MachineError::functor_stub(clause_name!(caller), arity);
let h = self.heap.h();
let addr = self.heap.to_unifiable(
HeapCellValue::Atom(atom.clone(), spec.clone())
);
return Err(self.error_form(
MachineError::existence_error(h + 1, ExistenceError::Stream(addr)),
stub,
));
}
}
} else {
unreachable!()
}
}
Addr::Stream(h) => {
if let HeapCellValue::Stream(ref stream) = &self.heap[h] {
stream.clone()
} else {
unreachable!()
}
}
_ => {
let stub = MachineError::functor_stub(clause_name!(caller), arity);
return Err(self.error_form(
MachineError::domain_error(DomainErrorType::StreamOrAlias, addr),
stub,
));
}
})
}
pub(crate)
fn open_parsing_stream(
&self,
stream: Stream,
stub_name: &'static str,
stub_arity: usize,
) -> Result<PrologStream, MachineStub> {
match parsing_stream(stream) {
Ok(stream) => {
Ok(stream)
}
Err(e) => {
let stub = MachineError::functor_stub(clause_name!(stub_name), stub_arity);
let err = MachineError::session_error(
self.heap.h(),
SessionError::from(e),
);
Err(self.error_form(err, stub))
}
}
}
pub(crate)
fn open_permission_error<T: PermissionError>(
&self,
culprit: T,
stub_name: &'static str,
stub_arity: usize,
) -> MachineStub {
let stub = MachineError::functor_stub(clause_name!(stub_name), stub_arity);
let err = MachineError::permission_error(
self.heap.h(),
Permission::Open,
"source_sink",
culprit,
);
return self.error_form(err, stub);
}
pub(crate)
fn occupied_alias_permission_error(
&self,
alias: ClauseName,
stub_name: &'static str,
stub_arity: usize,
) -> MachineStub {
let stub = MachineError::functor_stub(clause_name!(stub_name), stub_arity);
let err = MachineError::permission_error(
self.heap.h(),
Permission::Open,
"source_sink",
functor!("alias", [clause_name(alias)]),
);
return self.error_form(err, stub);
}
pub(crate)
fn reposition_error(
&self,
stub_name: &'static str,
stub_arity: usize,
) -> MachineStub {
let stub = MachineError::functor_stub(clause_name!(stub_name), stub_arity);
let rep_stub = functor!("reposition", [atom("true")]);
let err = MachineError::permission_error(
self.heap.h(),
Permission::Open,
"source_sink",
rep_stub,
);
return self.error_form(err, stub);
}
}
impl Read for Stream {
fn read(&mut self, buf: &mut [u8]) -> std::io::Result<usize> {
match *self.stream_inst.0.borrow_mut() {
StreamInstance::File(ref mut file) => {
file.read(buf)
}
StreamInstance::TcpStream(ref mut tcp_stream) => {
tcp_stream.read(buf)
}
StreamInstance::ReadlineStream(ref mut rl_stream) => {
rl_stream.read(buf)
}
StreamInstance::DynReadSource(ref mut src) => {
src.read(buf)
}
StreamInstance::Bytes(ref mut cursor) => {
cursor.read(buf)
}
/*
StreamInstance::Stdin => {
stdin().read(buf)
}
*/
StreamInstance::Stdout | StreamInstance::Null => {
Err(std::io::Error::new(
ErrorKind::PermissionDenied,
StreamError::ReadFromOutputStream,
))
}
}
}
}
impl Write for Stream {
fn write(&mut self, buf: &[u8]) -> std::io::Result<usize> {
match *self.stream_inst.0.borrow_mut() {
StreamInstance::File(ref mut file) => {
file.write(buf)
}
StreamInstance::TcpStream(ref mut tcp_stream) => {
tcp_stream.write(buf)
}
StreamInstance::Bytes(ref mut cursor) => {
cursor.write(buf)
}
StreamInstance::Stdout => {
stdout().write(buf)
}
_ => {
Err(std::io::Error::new(
ErrorKind::PermissionDenied,
StreamError::WriteToInputStream,
))
}
}
}
fn flush(&mut self) -> std::io::Result<()> {
match *self.stream_inst.0.borrow_mut() {
StreamInstance::File(ref mut file) => {
file.flush()
}
StreamInstance::TcpStream(ref mut tcp_stream) => {
tcp_stream.flush()
}
StreamInstance::Bytes(ref mut cursor) => {
cursor.flush()
}
StreamInstance::Stdout => {
stdout().flush()
}
_ => {
Err(std::io::Error::new(
ErrorKind::PermissionDenied,
StreamError::FlushToInputStream,
))
}
}
}
}
//TODO: write a Seek instance.