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5124587c96
janet/src/core/io.c
Calvin Rose f2313b9959 file/read on eof will return nil. 
Also add documentation for :exit in import.
Address issue #91
Partially adress issue #93
2019-05-14 11:05:19 -04:00

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/*
* Copyright (c) 2019 Calvin Rose
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to
* deal in the Software without restriction, including without limitation the
* rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
* sell copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
* IN THE SOFTWARE.
*/
/* Compiler feature test macros for things */
#define _DEFAULT_SOURCE
#define _BSD_SOURCE
#include <stdio.h>
#include <errno.h>
#ifndef JANET_AMALG
#include <janet.h>
#include "util.h"
#endif
#define IO_WRITE 1
#define IO_READ 2
#define IO_APPEND 4
#define IO_UPDATE 8
#define IO_NOT_CLOSEABLE 16
#define IO_CLOSED 32
#define IO_BINARY 64
#define IO_SERIALIZABLE 128
#define IO_PIPED 256
typedef struct IOFile IOFile;
struct IOFile {
FILE *file;
int flags;
};
static int cfun_io_gc(void *p, size_t len);
static Janet io_file_get(void *p, Janet);
JanetAbstractType cfun_io_filetype = {
"core/file",
cfun_io_gc,
NULL,
io_file_get,
NULL,
NULL,
NULL,
NULL
};
/* Check arguments to fopen */
static int checkflags(const uint8_t *str) {
int flags = 0;
int32_t i;
int32_t len = janet_string_length(str);
if (!len || len > 3)
janet_panic("file mode must have a length between 1 and 3");
switch (*str) {
default:
janet_panicf("invalid flag %c, expected w, a, or r", *str);
break;
case 'w':
flags |= IO_WRITE;
break;
case 'a':
flags |= IO_APPEND;
break;
case 'r':
flags |= IO_READ;
break;
}
for (i = 1; i < len; i++) {
switch (str[i]) {
default:
janet_panicf("invalid flag %c, expected + or b", str[i]);
break;
case '+':
if (flags & IO_UPDATE) return -1;
flags |= IO_UPDATE;
break;
case 'b':
if (flags & IO_BINARY) return -1;
flags |= IO_BINARY;
break;
}
}
return flags;
}
static Janet makef(FILE *f, int flags) {
IOFile *iof = (IOFile *) janet_abstract(&cfun_io_filetype, sizeof(IOFile));
iof->file = f;
iof->flags = flags;
return janet_wrap_abstract(iof);
}
/* Open a process */
#ifdef __EMSCRIPTEN__
static Janet cfun_io_popen(int32_t argc, Janet *argv) {
(void) argc;
(void) argv;
janet_panic("not implemented on this platform");
return janet_wrap_nil();
}
#else
static Janet cfun_io_popen(int32_t argc, Janet *argv) {
janet_arity(argc, 1, 2);
const uint8_t *fname = janet_getstring(argv, 0);
const uint8_t *fmode = NULL;
int flags;
if (argc == 2) {
fmode = janet_getkeyword(argv, 1);
if (janet_string_length(fmode) != 1 ||
!(fmode[0] == 'r' || fmode[0] == 'w')) {
janet_panicf("invalid file mode :%S, expected :r or :w", fmode);
}
flags = IO_PIPED | (fmode[0] == 'r' ? IO_READ : IO_WRITE);
} else {
fmode = (const uint8_t *)"r";
flags = IO_PIPED | IO_READ;
}
#ifdef JANET_WINDOWS
#define popen _popen
#endif
FILE *f = popen((const char *)fname, (const char *)fmode);
if (!f) {
return janet_wrap_nil();
}
return makef(f, flags);
}
#endif
static Janet cfun_io_fopen(int32_t argc, Janet *argv) {
janet_arity(argc, 1, 2);
const uint8_t *fname = janet_getstring(argv, 0);
const uint8_t *fmode;
int flags;
if (argc == 2) {
fmode = janet_getkeyword(argv, 1);
flags = checkflags(fmode);
} else {
fmode = (const uint8_t *)"r";
flags = IO_READ;
}
FILE *f = fopen((const char *)fname, (const char *)fmode);
return f ? makef(f, flags) : janet_wrap_nil();
}
/* Read up to n bytes into buffer. */
static void read_chunk(IOFile *iof, JanetBuffer *buffer, int32_t nBytesMax) {
if (!(iof->flags & (IO_READ | IO_UPDATE)))
janet_panic("file is not readable");
janet_buffer_extra(buffer, nBytesMax);
size_t ntoread = nBytesMax;
size_t nread = fread((char *)(buffer->data + buffer->count), 1, ntoread, iof->file);
if (nread != ntoread && ferror(iof->file))
janet_panic("could not read file");
buffer->count += (int32_t) nread;
}
/* Read a certain number of bytes into memory */
static Janet cfun_io_fread(int32_t argc, Janet *argv) {
janet_arity(argc, 2, 3);
IOFile *iof = janet_getabstract(argv, 0, &cfun_io_filetype);
if (iof->flags & IO_CLOSED) janet_panic("file is closed");
JanetBuffer *buffer;
if (argc == 2) {
buffer = janet_buffer(0);
} else {
buffer = janet_getbuffer(argv, 2);
}
int32_t bufstart = buffer->count;
if (janet_checktype(argv[1], JANET_KEYWORD)) {
const uint8_t *sym = janet_unwrap_keyword(argv[1]);
if (!janet_cstrcmp(sym, "all")) {
/* Read whole file */
int status = fseek(iof->file, 0, SEEK_SET);
if (status) {
/* backwards fseek did not work (stream like popen) */
int32_t sizeBefore;
do {
sizeBefore = buffer->count;
read_chunk(iof, buffer, 1024);
} while (sizeBefore < buffer->count);
} else {
fseek(iof->file, 0, SEEK_END);
long fsize = ftell(iof->file);
if (fsize < 0) {
janet_panicf("could not get file size of %v", argv[0]);
}
if (fsize > (INT32_MAX)) {
janet_panic("file to large to read into buffer");
}
fseek(iof->file, 0, SEEK_SET);
read_chunk(iof, buffer, (int32_t) fsize);
}
/* Never return nil for :all */
return janet_wrap_buffer(buffer);
} else if (!janet_cstrcmp(sym, "line")) {
for (;;) {
int x = fgetc(iof->file);
if (x != EOF) janet_buffer_push_u8(buffer, (uint8_t)x);
if (x == EOF || x == '\n') break;
}
} else {
janet_panicf("expected one of :all, :line, got %v", argv[1]);
}
} else {
int32_t len = janet_getinteger(argv, 1);
if (len < 0) janet_panic("expected positive integer");
read_chunk(iof, buffer, len);
}
if (bufstart == buffer->count) return janet_wrap_nil();
return janet_wrap_buffer(buffer);
}
/* Write bytes to a file */
static Janet cfun_io_fwrite(int32_t argc, Janet *argv) {
janet_arity(argc, 1, -1);
IOFile *iof = janet_getabstract(argv, 0, &cfun_io_filetype);
if (iof->flags & IO_CLOSED)
janet_panic("file is closed");
if (!(iof->flags & (IO_WRITE | IO_APPEND | IO_UPDATE)))
janet_panic("file is not writeable");
int32_t i;
/* Verify all arguments before writing to file */
for (i = 1; i < argc; i++)
janet_getbytes(argv, i);
for (i = 1; i < argc; i++) {
JanetByteView view = janet_getbytes(argv, i);
if (view.len) {
if (!fwrite(view.bytes, view.len, 1, iof->file)) {
janet_panic("error writing to file");
}
}
}
return argv[0];
}
/* Flush the bytes in the file */
static Janet cfun_io_fflush(int32_t argc, Janet *argv) {
janet_fixarity(argc, 1);
IOFile *iof = janet_getabstract(argv, 0, &cfun_io_filetype);
if (iof->flags & IO_CLOSED)
janet_panic("file is closed");
if (!(iof->flags & (IO_WRITE | IO_APPEND | IO_UPDATE)))
janet_panic("file is not writeable");
if (fflush(iof->file))
janet_panic("could not flush file");
return argv[0];
}
/* Cleanup a file */
static int cfun_io_gc(void *p, size_t len) {
(void) len;
IOFile *iof = (IOFile *)p;
if (!(iof->flags & (IO_NOT_CLOSEABLE | IO_CLOSED))) {
return fclose(iof->file);
}
return 0;
}
/* Close a file */
static Janet cfun_io_fclose(int32_t argc, Janet *argv) {
janet_fixarity(argc, 1);
IOFile *iof = janet_getabstract(argv, 0, &cfun_io_filetype);
if (iof->flags & IO_CLOSED)
janet_panic("file is closed");
if (iof->flags & (IO_NOT_CLOSEABLE))
janet_panic("file not closable");
if (iof->flags & IO_PIPED) {
#ifdef JANET_WINDOWS
#define pclose _pclose
#endif
if (pclose(iof->file)) janet_panic("could not close file");
} else {
if (fclose(iof->file)) janet_panic("could not close file");
}
iof->flags |= IO_CLOSED;
return argv[0];
}
/* Seek a file */
static Janet cfun_io_fseek(int32_t argc, Janet *argv) {
janet_arity(argc, 2, 3);
IOFile *iof = janet_getabstract(argv, 0, &cfun_io_filetype);
if (iof->flags & IO_CLOSED)
janet_panic("file is closed");
long int offset = 0;
int whence = SEEK_CUR;
if (argc >= 2) {
const uint8_t *whence_sym = janet_getkeyword(argv, 1);
if (!janet_cstrcmp(whence_sym, "cur")) {
whence = SEEK_CUR;
} else if (!janet_cstrcmp(whence_sym, "set")) {
whence = SEEK_SET;
} else if (!janet_cstrcmp(whence_sym, "end")) {
whence = SEEK_END;
} else {
janet_panicf("expected one of :cur, :set, :end, got %v", argv[1]);
}
if (argc == 3) {
offset = (long) janet_getinteger64(argv, 2);
}
}
if (fseek(iof->file, offset, whence)) janet_panic("error seeking file");
return argv[0];
}
static JanetMethod io_file_methods[] = {
{"close", cfun_io_fclose},
{"read", cfun_io_fread},
{"write", cfun_io_fwrite},
{"flush", cfun_io_fflush},
{"seek", cfun_io_fseek},
{NULL, NULL}
};
static Janet io_file_get(void *p, Janet key) {
(void) p;
if (!janet_checktype(key, JANET_KEYWORD))
janet_panicf("expected keyword, got %v", key);
return janet_getmethod(janet_unwrap_keyword(key), io_file_methods);
}
FILE *janet_dynfile(const char *name, FILE *def) {
Janet x = janet_dyn(name);
if (!janet_checktype(x, JANET_ABSTRACT)) return def;
void *abstract = janet_unwrap_abstract(x);
if (janet_abstract_type(abstract) != &cfun_io_filetype) return def;
IOFile *iofile = abstract;
return iofile->file;
}
static Janet cfun_io_print(int32_t argc, Janet *argv) {
FILE *f = janet_dynfile("out", stdout);
for (int32_t i = 0; i < argc; ++i) {
int32_t j, len;
const uint8_t *vstr = janet_to_string(argv[i]);
len = janet_string_length(vstr);
for (j = 0; j < len; ++j) {
putc(vstr[j], f);
}
}
putc('\n', f);
return janet_wrap_nil();
}
static const JanetReg io_cfuns[] = {
{
"print", cfun_io_print,
JDOC("(print & xs)\n\n"
"Print values to the console (standard out). Value are converted "
"to strings if they are not already. After printing all values, a "
"newline character is printed. Returns nil.")
},
{
"file/open", cfun_io_fopen,
JDOC("(file/open path [,mode])\n\n"
"Open a file. path is an absolute or relative path, and "
"mode is a set of flags indicating the mode to open the file in. "
"mode is a keyword where each character represents a flag. If the file "
"cannot be opened, returns nil, otherwise returns the new file handle. "
"Mode flags:\n\n"
"\tr - allow reading from the file\n"
"\tw - allow writing to the file\n"
"\ta - append to the file\n"
"\tb - open the file in binary mode (rather than text mode)\n"
"\t+ - append to the file instead of overwriting it")
},
{
"file/close", cfun_io_fclose,
JDOC("(file/close f)\n\n"
"Close a file and release all related resources. When you are "
"done reading a file, close it to prevent a resource leak and let "
"other processes read the file.")
},
{
"file/read", cfun_io_fread,
JDOC("(file/read f what [,buf])\n\n"
"Read a number of bytes from a file into a buffer. A buffer can "
"be provided as an optional fourth argument, otherwise a new buffer "
"is created. 'what' can either be an integer or a keyword. Returns the "
"buffer with file contents. "
"Values for 'what':\n\n"
"\t:all - read the whole file\n"
"\t:line - read up to and including the next newline character\n"
"\tn (integer) - read up to n bytes from the file")
},
{
"file/write", cfun_io_fwrite,
JDOC("(file/write f bytes)\n\n"
"Writes to a file. 'bytes' must be string, buffer, or symbol. Returns the "
"file.")
},
{
"file/flush", cfun_io_fflush,
JDOC("(file/flush f)\n\n"
"Flush any buffered bytes to the file system. In most files, writes are "
"buffered for efficiency reasons. Returns the file handle.")
},
{
"file/seek", cfun_io_fseek,
JDOC("(file/seek f [,whence [,n]])\n\n"
"Jump to a relative location in the file. 'whence' must be one of\n\n"
"\t:cur - jump relative to the current file location\n"
"\t:set - jump relative to the beginning of the file\n"
"\t:end - jump relative to the end of the file\n\n"
"By default, 'whence' is :cur. Optionally a value n may be passed "
"for the relative number of bytes to seek in the file. n may be a real "
"number to handle large files of more the 4GB. Returns the file handle.")
},
{
"file/popen", cfun_io_popen,
JDOC("(file/popen path [,mode])\n\n"
"Open a file that is backed by a process. The file must be opened in either "
"the :r (read) or the :w (write) mode. In :r mode, the stdout of the "
"process can be read from the file. In :w mode, the stdin of the process "
"can be written to. Returns the new file.")
},
{NULL, NULL, NULL}
};
/* C API */
FILE *janet_getfile(const Janet *argv, int32_t n, int *flags) {
IOFile *iof = janet_getabstract(argv, n, &cfun_io_filetype);
if (NULL != flags) *flags = iof->flags;
return iof->file;
}
/* Module entry point */
void janet_lib_io(JanetTable *env) {
janet_core_cfuns(env, NULL, io_cfuns);
/* stdout */
janet_core_def(env, "stdout",
makef(stdout, IO_APPEND | IO_NOT_CLOSEABLE | IO_SERIALIZABLE),
JDOC("The standard output file."));
/* stderr */
janet_core_def(env, "stderr",
makef(stderr, IO_APPEND | IO_NOT_CLOSEABLE | IO_SERIALIZABLE),
JDOC("The standard error file."));
/* stdin */
janet_core_def(env, "stdin",
makef(stdin, IO_READ | IO_NOT_CLOSEABLE | IO_SERIALIZABLE),
JDOC("The standard input file."));
}
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