factor/vm/io.cpp

254 lines
5.9 KiB
C++

#include "master.hpp"
namespace factor {
// Simple wrappers for ANSI C I/O functions, used for bootstrapping.
// Note the ugly loop logic in almost every function; we have to handle EINTR
// and restart the operation if the system call was interrupted. Naive
// applications don't do this, but then they quickly fail if one enables
// itimer()s or other signals.
// The Factor library provides platform-specific code for Unix and Windows
// with many more capabilities so these words are not usually used in
// normal operation.
size_t raw_fread(void* ptr, size_t size, size_t nitems, FILE* stream) {
FACTOR_ASSERT(nitems > 0);
size_t items_read = 0;
do {
size_t ret = fread((void*)((int*)ptr + items_read * size), size,
nitems - items_read, stream);
if (ret == 0) {
if (feof(stream)) {
break;
}
else if (errno != EINTR) {
return 0;
}
}
items_read += ret;
} while (items_read != nitems);
return items_read;
}
// Call fclose() once only. Issues #1335, #908.
int raw_fclose(FILE* stream) {
if (fclose(stream) == EOF && errno != EINTR)
return -1;
return 0;
}
void factor_vm::init_c_io() {
special_objects[OBJ_STDIN] = allot_alien(false_object, (cell)stdin);
special_objects[OBJ_STDOUT] = allot_alien(false_object, (cell)stdout);
special_objects[OBJ_STDERR] = allot_alien(false_object, (cell)stderr);
}
// Allocates memory
void factor_vm::io_error_if_not_EINTR() {
if (errno == EINTR)
return;
general_error(ERROR_IO, tag_fixnum(errno), false_object);
}
FILE* factor_vm::safe_fopen(char* filename, const char* mode) {
FILE* file;
for (;;) {
file = fopen(filename, mode);
if (file == NULL)
io_error_if_not_EINTR();
else
break;
}
return file;
}
int factor_vm::safe_fgetc(FILE* stream) {
int c;
for (;;) {
c = getc(stream);
if (c == EOF) {
if (feof(stream))
return EOF;
else
io_error_if_not_EINTR();
} else
break;
}
return c;
}
size_t factor_vm::safe_fread(void* ptr, size_t size, size_t nitems,
FILE* stream) {
size_t ret = raw_fread(ptr, size, nitems, stream);
if (ret == 0 && !feof(stream))
io_error_if_not_EINTR();
return ret;
}
void factor_vm::safe_fputc(int c, FILE* stream) {
for (;;) {
if (putc(c, stream) == EOF)
io_error_if_not_EINTR();
else
break;
}
}
size_t factor_vm::safe_fwrite(void* ptr, size_t size, size_t nitems,
FILE* stream) {
size_t items_written = 0;
size_t ret = 0;
do {
ret = fwrite((void*)((int*)ptr + items_written * size), size,
nitems - items_written, stream);
if (ret == 0)
io_error_if_not_EINTR();
items_written += ret;
} while (items_written != nitems);
return items_written;
}
int factor_vm::safe_ftell(FILE* stream) {
off_t offset;
for (;;) {
if ((offset = FTELL(stream)) == -1)
io_error_if_not_EINTR();
else
break;
}
return offset;
}
void factor_vm::safe_fseek(FILE* stream, off_t offset, int whence) {
switch (whence) {
case 0:
whence = SEEK_SET;
break;
case 1:
whence = SEEK_CUR;
break;
case 2:
whence = SEEK_END;
break;
default:
critical_error("Bad value for whence", whence);
}
for (;;) {
if (FSEEK(stream, offset, whence) == -1)
io_error_if_not_EINTR();
else
break;
}
}
void factor_vm::safe_fflush(FILE* stream) {
for (;;) {
if (fflush(stream) == EOF)
io_error_if_not_EINTR();
else
break;
}
}
void factor_vm::primitive_fopen() {
data_root<byte_array> mode(ctx->pop(), this);
data_root<byte_array> path(ctx->pop(), this);
check_tagged(mode);
check_tagged(path);
FILE* file;
file = safe_fopen((char*)(path.untagged() + 1),
(char*)(mode.untagged() + 1));
ctx->push(allot_alien((cell)file));
}
FILE* factor_vm::pop_file_handle() { return (FILE*)alien_offset(ctx->pop()); }
FILE* factor_vm::peek_file_handle() { return (FILE*)alien_offset(ctx->peek()); }
void factor_vm::primitive_fgetc() {
FILE* file = peek_file_handle();
int c = safe_fgetc(file);
if (c == EOF && feof(file)) {
clearerr(file);
ctx->replace(false_object);
} else
ctx->replace(tag_fixnum(c));
}
// Allocates memory (from_unsigned_cell())
void factor_vm::primitive_fread() {
FILE* file = pop_file_handle();
void* buf = (void*)alien_offset(ctx->pop());
cell size = unbox_array_size();
if (size == 0) {
ctx->push(from_unsigned_cell(0));
return;
}
size_t c = safe_fread(buf, 1, size, file);
if (c == 0 || feof(file))
clearerr(file);
ctx->push(from_unsigned_cell(c));
}
void factor_vm::primitive_fputc() {
FILE* file = pop_file_handle();
fixnum ch = to_fixnum(ctx->pop());
safe_fputc((int)ch, file);
}
void factor_vm::primitive_fwrite() {
FILE* file = pop_file_handle();
cell length = to_cell(ctx->pop());
char* text = alien_offset(ctx->pop());
if (length == 0)
return;
size_t written = safe_fwrite(text, 1, length, file);
if (written != length)
io_error_if_not_EINTR();
}
void factor_vm::primitive_ftell() {
FILE* file = peek_file_handle();
ctx->replace(from_signed_8(safe_ftell(file)));
}
void factor_vm::primitive_fseek() {
FILE* file = pop_file_handle();
int whence = (int)to_fixnum(ctx->pop());
off_t offset = (off_t)to_signed_8(ctx->pop());
safe_fseek(file, offset, whence);
}
void factor_vm::primitive_fflush() {
FILE* file = pop_file_handle();
safe_fflush(file);
}
void factor_vm::primitive_fclose() {
FILE* file = pop_file_handle();
if (raw_fclose(file) == -1)
io_error_if_not_EINTR();
}
// This function is used by FFI I/O. Accessing the errno global directly is
// not portable, since on some libc's errno is not a global but a funky macro that
// reads thread-local storage.
VM_C_API int err_no() { return errno; }
VM_C_API void set_err_no(int err) { errno = err; }
}