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Fix file.read to handle popen'ed files better (allow read with :all).

This commit is contained in:
Calvin Rose 2018-06-26 09:37:34 -04:00
parent 23dcfb986e
commit 9805bfb635

View File

@ -196,11 +196,24 @@ static int dst_io_fopen(DstArgs args) {
DST_RETURN(args, f ? makef(f, flags) : dst_wrap_nil());
}
/* Read up to n bytes into buffer. Return error string if error. */
static const char *read_chunk(IOFile *iof, DstBuffer *buffer, int32_t nBytesMax) {
if (!(iof->flags & (IO_READ | IO_UPDATE)))
return "file is not readable";
/* Ensure buffer size */
if (dst_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 += nread;
return NULL;
}
/* Read a certain number of bytes into memory */
static int dst_io_fread(DstArgs args) {
DstBuffer *b;
int32_t len;
size_t ntoread, nread;
IOFile *iof = checkfile(args, 0);
if (!iof) return 1;
if (iof->flags & IO_CLOSED)
@ -211,13 +224,23 @@ static int dst_io_fread(DstArgs args) {
const uint8_t *sym = dst_unwrap_symbol(args.v[1]);
if (!dst_cstrcmp(sym, ":all")) {
/* Read whole file */
long fsize;
fseek(iof->file, 0, SEEK_END);
fsize = ftell(iof->file);
fseek(iof->file, 0, SEEK_SET);
if (fsize > INT32_MAX) DST_THROW(args, "buffer overflow");
len = fsize;
/* Fall through to normal code */
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) DST_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) DST_THROW(args, "buffer overflow");
const char *maybeErr = read_chunk(iof, b, (int32_t) fsize);;
if (maybeErr) DST_THROW(args, maybeErr);
}
} else if (!dst_cstrcmp(sym, ":line")) {
for (;;) {
int x = fgetc(iof->file);
@ -225,23 +248,17 @@ static int dst_io_fread(DstArgs args) {
DST_THROW(args, "buffer overflow");
if (x == EOF || x == '\n') break;
}
DST_RETURN(args, dst_wrap_buffer(b));
} else {
DST_THROW(args, "expected one of :all, :line");
}
} else if (!dst_checktype(args.v[1], DST_INTEGER)) {
DST_THROW(args, "expected positive integer");
} else {
len = dst_unwrap_integer(args.v[1]);
int32_t len = dst_unwrap_integer(args.v[1]);
if (len < 0) DST_THROW(args, "expected positive integer");
const char *maybeErr = read_chunk(iof, b, len);
if (maybeErr) DST_THROW(args, maybeErr);
}
if (!(iof->flags & (IO_READ | IO_UPDATE))) DST_THROW(args, "file is not readable");
/* Ensure buffer size */
if (dst_buffer_extra(b, len)) DST_THROW(args, "buffer overflow");
ntoread = len;
nread = fread((char *)(b->data + b->count), 1, ntoread, iof->file);
if (nread != ntoread && ferror(iof->file)) DST_THROW(args, "could not read file");
b->count += nread;
DST_RETURN(args, dst_wrap_buffer(b));
}