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janet/src/core/io.c

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/*
* Copyright (c) 2018 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 <janet/janet.h>
#include <errno.h>
#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 janet_io_gc(void *p, size_t len);
JanetAbstractType janet_io_filetype = {
":core/file",
janet_io_gc,
NULL
};
/* Check argupments to fopen */
static int checkflags(const uint8_t *str, int32_t len) {
int flags = 0;
int32_t i;
if (!len || len > 3) return -1;
switch (*str) {
default:
return -1;
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:
return -1;
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;
}
/* Check file argument */
static IOFile *checkfile(JanetArgs args, int32_t n) {
IOFile *iof;
if (n >= args.n) {
*args.ret = janet_cstringv("expected core.file");
return NULL;
}
if (!janet_checktype(args.v[n], JANET_ABSTRACT)) {
*args.ret = janet_cstringv("expected core.file");
return NULL;
}
iof = (IOFile *) janet_unwrap_abstract(args.v[n]);
if (janet_abstract_type(iof) != &janet_io_filetype) {
*args.ret = janet_cstringv("expected core.file");
return NULL;
}
return iof;
}
/* Check buffer argument */
static JanetBuffer *checkbuffer(JanetArgs args, int32_t n, int optional) {
if (optional && n == args.n) {
return janet_buffer(0);
}
if (n >= args.n) {
*args.ret = janet_cstringv("expected buffer");
return NULL;
}
if (!janet_checktype(args.v[n], JANET_BUFFER)) {
*args.ret = janet_cstringv("expected buffer");
return NULL;
}
return janet_unwrap_abstract(args.v[n]);
}
static Janet makef(FILE *f, int flags) {
IOFile *iof = (IOFile *) janet_abstract(&janet_io_filetype, sizeof(IOFile));
iof->file = f;
iof->flags = flags;
return janet_wrap_abstract(iof);
}
/* Open a process */
static int janet_io_popen(JanetArgs args) {
const uint8_t *fname, *fmode;
int32_t modelen;
FILE *f;
int flags;
JANET_MINARITY(args, 1);
JANET_MAXARITY(args, 2);
JANET_ARG_STRING(fname, args, 0);
if (args.n == 2) {
if (!janet_checktype(args.v[1], JANET_STRING) &&
!janet_checktype(args.v[1], JANET_SYMBOL))
JANET_THROW(args, "expected string mode");
fmode = janet_unwrap_string(args.v[1]);
modelen = janet_string_length(fmode);
} else {
fmode = (const uint8_t *)"r";
modelen = 1;
}
if (fmode[0] == ':') {
fmode++;
modelen--;
}
if (modelen != 1 || !(fmode[0] == 'r' || fmode[0] == 'w')) {
JANET_THROW(args, "invalid file mode");
}
flags = (fmode[0] == 'r') ? IO_PIPED | IO_READ : IO_PIPED | IO_WRITE;
#ifdef JANET_WINDOWS
#define popen _popen
#endif
#ifdef __EMSCRIPTEN__
#define popen(A, B) (errno = 0, NULL)
#endif
f = popen((const char *)fname, (const char *)fmode);
if (!f) {
if (errno == EMFILE) {
JANET_THROW(args, "too many streams are open");
}
JANET_THROW(args, "could not open file");
}
JANET_RETURN(args, makef(f, flags));
}
/* Open a a file and return a userdata wrapper around the C file API. */
static int janet_io_fopen(JanetArgs args) {
const uint8_t *fname, *fmode;
int32_t modelen;
FILE *f;
int flags;
JANET_MINARITY(args, 1);
JANET_MAXARITY(args, 2);
JANET_ARG_STRING(fname, args, 0);
if (args.n == 2) {
if (!janet_checktype(args.v[1], JANET_STRING) &&
!janet_checktype(args.v[1], JANET_SYMBOL))
JANET_THROW(args, "expected string mode");
fmode = janet_unwrap_string(args.v[1]);
modelen = janet_string_length(fmode);
} else {
fmode = (const uint8_t *)"r";
modelen = 1;
}
if (fmode[0] == ':') {
fmode++;
modelen--;
}
if ((flags = checkflags(fmode, modelen)) < 0) {
JANET_THROW(args, "invalid file mode");
}
f = fopen((const char *)fname, (const char *)fmode);
JANET_RETURN(args, f ? makef(f, flags) : janet_wrap_nil());
}
/* Read up to n bytes into buffer. Return error string if error. */
static const char *read_chunk(IOFile *iof, JanetBuffer *buffer, int32_t nBytesMax) {
if (!(iof->flags & (IO_READ | IO_UPDATE)))
return "file is not readable";
/* Ensure buffer size */
if (janet_buffer_extra(buffer, nBytesMax))
return "buffer overflow";
size_t ntoread = nBytesMax;
size_t nread = fread((char *)(buffer->data + buffer->count), 1, ntoread, iof->file);
if (nread != ntoread && ferror(iof->file))
return "could not read file";
buffer->count += (int32_t) nread;
return NULL;
}
/* Read a certain number of bytes into memory */
static int janet_io_fread(JanetArgs args) {
JanetBuffer *b;
IOFile *iof = checkfile(args, 0);
if (!iof) return 1;
if (iof->flags & IO_CLOSED)
JANET_THROW(args, "file is closed");
b = checkbuffer(args, 2, 1);
if (!b) return 1;
if (janet_checktype(args.v[1], JANET_SYMBOL)) {
const uint8_t *sym = janet_unwrap_symbol(args.v[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 = b->count;
const char *maybeErr = read_chunk(iof, b, 1024);
if (maybeErr) JANET_THROW(args, maybeErr);
} while (sizeBefore < b->count);
} else {
fseek(iof->file, 0, SEEK_END);
long fsize = ftell(iof->file);
fseek(iof->file, 0, SEEK_SET);
if (fsize > INT32_MAX) JANET_THROW(args, "buffer overflow");
const char *maybeErr = read_chunk(iof, b, (int32_t) fsize);;
if (maybeErr) JANET_THROW(args, maybeErr);
}
} else if (!janet_cstrcmp(sym, ":line")) {
for (;;) {
int x = fgetc(iof->file);
if (x != EOF && janet_buffer_push_u8(b, (uint8_t)x))
JANET_THROW(args, "buffer overflow");
if (x == EOF || x == '\n') break;
}
} else {
JANET_THROW(args, "expected one of :all, :line");
}
} else if (!janet_checkint(args.v[1])) {
JANET_THROW(args, "expected positive integer");
} else {
int32_t len = janet_unwrap_integer(args.v[1]);
if (len < 0) JANET_THROW(args, "expected positive integer");
const char *maybeErr = read_chunk(iof, b, len);
if (maybeErr) JANET_THROW(args, maybeErr);
}
JANET_RETURN(args, janet_wrap_buffer(b));
}
/* Write bytes to a file */
static int janet_io_fwrite(JanetArgs args) {
int32_t len, i;
const uint8_t *str;
IOFile *iof = checkfile(args, 0);
if (!iof) return 1;
if (iof->flags & IO_CLOSED)
JANET_THROW(args, "file is closed");
if (!(iof->flags & (IO_WRITE | IO_APPEND | IO_UPDATE)))
JANET_THROW(args, "file is not writeable");
for (i = 1; i < args.n; i++) {
JANET_CHECKMANY(args, i, JANET_TFLAG_BYTES);
}
for (i = 1; i < args.n; i++) {
JANET_ARG_BYTES(str, len, args, i);
if (len) {
if (!fwrite(str, len, 1, iof->file)) JANET_THROW(args, "error writing to file");
}
}
JANET_RETURN(args, janet_wrap_abstract(iof));
}
/* Flush the bytes in the file */
static int janet_io_fflush(JanetArgs args) {
IOFile *iof = checkfile(args, 0);
if (!iof) return 1;
if (iof->flags & IO_CLOSED)
JANET_THROW(args, "file is closed");
if (!(iof->flags & (IO_WRITE | IO_APPEND | IO_UPDATE)))
JANET_THROW(args, "file is not flushable");
if (fflush(iof->file)) JANET_THROW(args, "could not flush file");
JANET_RETURN(args, janet_wrap_abstract(iof));
}
/* Cleanup a file */
static int janet_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 int janet_io_fclose(JanetArgs args) {
IOFile *iof = checkfile(args, 0);
if (!iof) return 1;
if (iof->flags & (IO_CLOSED))
JANET_THROW(args, "file already closed");
if (iof->flags & (IO_NOT_CLOSEABLE))
JANET_THROW(args, "file not closable");
if (iof->flags & IO_PIPED) {
#ifdef JANET_WINDOWS
#define pclose _pclose
#endif
if (pclose(iof->file)) JANET_THROW(args, "could not close file");
} else {
if (fclose(iof->file)) JANET_THROW(args, "could not close file");
}
iof->flags |= IO_CLOSED;
JANET_RETURN(args, janet_wrap_abstract(iof));
}
/* Seek a file */
static int janet_io_fseek(JanetArgs args) {
long int offset = 0;
int whence = SEEK_CUR;
IOFile *iof = checkfile(args, 0);
if (!iof) return 1;
if (iof->flags & IO_CLOSED)
JANET_THROW(args, "file is closed");
if (args.n >= 2) {
const uint8_t *whence_sym;
if (!janet_checktype(args.v[1], JANET_SYMBOL))
JANET_THROW(args, "expected symbol");
whence_sym = janet_unwrap_symbol(args.v[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_THROW(args, "expected one of :cur, :set, :end");
}
if (args.n >= 3) {
double doffset;
JANET_ARG_NUMBER(doffset, args, 2);
offset = (long int)doffset;
}
}
if (fseek(iof->file, offset, whence))
JANET_THROW(args, "error seeking file");
JANET_RETURN(args, args.v[0]);
}
static const JanetReg cfuns[] = {
{"file/open", janet_io_fopen,
"(file/open path [,mode])\n\n"
"Open a file. path is files 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 witing 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", janet_io_fclose,
"(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", janet_io_fread,
"(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", janet_io_fwrite,
"(file/write f bytes)\n\n"
"Writes to a file. 'bytes' must be string, buffer, or symbol. Returns the "
"file"
},
{"file/flush", janet_io_fflush,
"(file/flush f)\n\n"
"Flush any buffered bytes to the filesystem. In most files, writes are "
"buffered for efficiency reasons. Returns the file handle."
},
{"file/seek", janet_io_fseek,
"(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", janet_io_popen,
"(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}
};
/* Module entry point */
int janet_lib_io(JanetArgs args) {
JanetTable *env = janet_env(args);
janet_cfuns(env, NULL, cfuns);
/* stdout */
janet_def(env, "stdout",
makef(stdout, IO_APPEND | IO_NOT_CLOSEABLE | IO_SERIALIZABLE),
"The standard output file.");
/* stderr */
janet_def(env, "stderr",
makef(stderr, IO_APPEND | IO_NOT_CLOSEABLE | IO_SERIALIZABLE),
"The standard error file.");
/* stdin */
janet_def(env, "stdin",
makef(stdin, IO_READ | IO_NOT_CLOSEABLE | IO_SERIALIZABLE),
"The standard input file.");
return 0;
}
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