implement Ramfile;include "sys.m"; sys: Sys;include "draw.m";# synthesise a file that can be treated just like any other# file. limitations of file2chan mean that it's not possible# to know when an open should have truncated the file, so# we do the only possible thing, and truncate it when we get# a write at offset 0. thus it can be edited with an editor,# but can't be used to store seekable, writable data records# (unless the first record is never written)# there should be some way to determine when the file should# go away - file2chan sends a nil channel whenever the file# is closed by anyone, which is not good enough.stderr: ref Sys->FD;Ramfile: module { init: fn(nil: ref Draw->Context, argv: list of string);};init(nil: ref Draw->Context, argv: list of string){ sys = load Sys Sys->PATH; stderr = sys->fildes(2); if (len argv < 2 || len argv > 3) { sys->fprint(stderr, "usage: ramfile path [data]\n"); return; } path := hd tl argv; (dir, f) := pathsplit(path); if (sys->bind("#s", dir, Sys->MBEFORE|Sys->MCREATE) == -1) { sys->fprint(stderr, "ramfile: %r\n"); return; } fio := sys->file2chan(dir, f); if (fio == nil) { sys->fprint(stderr, "ramfile: file2chan failed: %r\n"); return; } data := array[0] of byte; if (tl tl argv != nil) data = array of byte hd tl tl argv; spawn server(fio, data); data = nil;}server(fio: ref Sys->FileIO, data: array of byte){ for (;;) alt { (offset, count, nil, rc) := <-fio.read => if (rc != nil) { if (offset > len data) rc <-= (nil, nil); else { end := offset + count; if (end > len data) end = len data; rc <-= (data[offset:end], nil); } } (offset, d, nil, wc) := <-fio.write => if (wc != nil) { if (offset == 0) data = array[0] of byte; end := offset + len d; if (end > len data) { ndata := array[end] of byte; ndata[0:] = data; data = ndata; ndata = nil; } data[offset:] = d; wc <-= (len d, nil); } }}pathsplit(p: string): (string, string){ for (i := len p - 1; i >= 0; i--) if (p[i] != '/') break; if (i < 0) return (p, nil); p = p[0:i+1]; for (i = len p - 1; i >=0; i--) if (p[i] == '/') break; if (i < 0) return (".", p); return (p[0:i+1], p[i+1:]);}
implement Ramfile;
include "sys.m";
sys: Sys;
include "draw.m";
# synthesise a file that can be treated just like any other
# file. limitations of file2chan mean that it's not possible
# to know when an open should have truncated the file, so
# we do the only possible thing, and truncate it when we get
# a write at offset 0. thus it can be edited with an editor,
# but can't be used to store seekable, writable data records
# (unless the first record is never written)
# there should be some way to determine when the file should
# go away - file2chan sends a nil channel whenever the file
# is closed by anyone, which is not good enough.
stderr: ref Sys->FD;
Ramfile: module {
init: fn(nil: ref Draw->Context, argv: list of string);
};
init(nil: ref Draw->Context, argv: list of string)
{
sys = load Sys Sys->PATH;
stderr = sys->fildes(2);
if (len argv < 2 || len argv > 3) {
sys->fprint(stderr, "usage: ramfile path [data]\n");
return;
}
path := hd tl argv;
(dir, f) := pathsplit(path);
if (sys->bind("#s", dir, Sys->MBEFORE|Sys->MCREATE) == -1) {
sys->fprint(stderr, "ramfile: %r\n");
return;
}
fio := sys->file2chan(dir, f);
if (fio == nil) {
sys->fprint(stderr, "ramfile: file2chan failed: %r\n");
return;
}
data := array[0] of byte;
if (tl tl argv != nil)
data = array of byte hd tl tl argv;
spawn server(fio, data);
data = nil;
}
server(fio: ref Sys->FileIO, data: array of byte)
{
for (;;) alt {
(offset, count, nil, rc) := <-fio.read =>
if (rc != nil) {
if (offset > len data)
rc <-= (nil, nil);
else {
end := offset + count;
if (end > len data)
end = len data;
rc <-= (data[offset:end], nil);
}
}
(offset, d, nil, wc) := <-fio.write =>
if (wc != nil) {
if (offset == 0)
data = array[0] of byte;
end := offset + len d;
if (end > len data) {
ndata := array[end] of byte;
ndata[0:] = data;
data = ndata;
ndata = nil;
}
data[offset:] = d;
wc <-= (len d, nil);
}
}
}
pathsplit(p: string): (string, string)
{
for (i := len p - 1; i >= 0; i--)
if (p[i] != '/')
break;
if (i < 0)
return (p, nil);
p = p[0:i+1];
for (i = len p - 1; i >=0; i--)
if (p[i] == '/')
break;
if (i < 0)
return (".", p);
return (p[0:i+1], p[i+1:]);
}