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|
implement Mashbuiltin;
#
# "history" builtin, defines:
#
include "mash.m";
include "mashparse.m";
mashlib: Mashlib;
chanfill: ChanFill;
Env: import mashlib;
sys, bufio: import mashlib;
Iobuf: import bufio;
Hcmd: adt
{
seek: int;
text: array of byte;
};
Reader: adt
{
fid: int;
offset: int;
hint: int;
next: cyclic ref Reader;
};
history: array of ref Hcmd;
lhist: int;
nhist: int;
seek: int;
readers: ref Reader;
eof := array[0] of byte;
#
# Interface to catch the use as a command.
#
init(nil: ref Draw->Context, args: list of string)
{
raise "fail: " + hd args + " not loaded";
}
#
# Used by whatis.
#
name(): string
{
return "history";
}
#
# Install commands.
#
mashinit(nil: list of string, lib: Mashlib, nil: Mashbuiltin, e: ref Env)
{
mashlib = lib;
if (mashlib->histchan != nil)
return;
mashlib->startserve = 1;
nhist = 0;
lhist = 256;
history = array[lhist] of ref Hcmd;
seek = 0;
(f, c) := e.servefile(mashlib->HISTF);
spawn servehist(f, c);
(f, c) = e.servefile(mashlib->MASHF);
spawn servemash(f, c);
}
mashcmd(nil: ref Env, nil: list of string)
{
}
addhist(b: array of byte)
{
if (nhist == lhist) {
n := 3 * nhist / 4;
part := history[:n];
part[:] = history[nhist - n:];
nhist = n;
}
history[nhist] = ref Hcmd(seek, b);
nhist++;
seek += len b;
}
getfid(fid: int, del: int): ref Reader
{
prev: ref Reader;
for (r := readers; r != nil; r = r.next) {
if (r.fid == fid) {
if (del) {
if (prev == nil)
readers = r.next;
else
prev.next = r.next;
return nil;
}
return r;
}
prev = r;
}
o := 0;
if (nhist > 0)
o = history[0].seek;
return readers = ref Reader(fid, o, 0, readers);
}
readhist(off, count, fid: int): (array of byte, string)
{
r := getfid(fid, 0);
off += r.offset;
if (nhist == 0 || off >= seek)
return (eof, nil);
i := r.hint;
if (i >= nhist)
i = nhist - 1;
s := history[i].seek;
if (off == s) {
r.hint = i + 1;
return (history[i].text, nil);
}
if (off > s) {
do {
if (++i == nhist)
break;
s = history[i].seek;
} while (off >= s);
i--;
} else {
do {
if (--i < 0)
return (eof, "data truncated");
s = history[i].seek;
} while (off < s);
}
r.hint = i + 1;
b := history[i].text;
if (off != s)
b = b[off - s:];
return (b, nil);
}
loadhist(data: array of byte, fid: int, wc: Sys->Rwrite, c: ref Sys->FileIO)
{
in: ref Iobuf;
if (chanfill == nil)
chanfill = load ChanFill ChanFill->PATH;
if (chanfill != nil)
in = chanfill->init(data, fid, wc, c, mashlib->bufio);
if (in == nil) {
in = bufio->sopen(string data);
if (in == nil) {
wc <-= (0, mashlib->errstr());
return;
}
wc <-= (len data, nil);
}
while ((s := in.gets('\n')) != nil)
addhist(array of byte s);
in.close();
}
servehist(f: string, c: ref Sys->FileIO)
{
mashlib->reap();
h := chan of array of byte;
mashlib->histchan = h;
for (;;) {
alt {
b := <-h =>
addhist(b);
(off, count, fid, rc) := <-c.read =>
if (rc == nil) {
getfid(fid, 1);
continue;
}
rc <-= readhist(off, count, fid);
(off, data, fid, wc) := <-c.write =>
if (wc != nil)
loadhist(data, fid, wc, c);
}
}
}
servemash(f: string, c: ref Sys->FileIO)
{
mashlib->reap();
for (;;) {
alt {
(off, count, fid, rc) := <-c.read =>
if (rc != nil)
rc <-= (nil, "not supported");
(off, data, fid, wc) := <-c.write =>
if (wc != nil) {
wc <-= (len data, nil);
if (mashlib->servechan != nil && len data > 0)
mashlib->servechan <-= data;
}
}
}
}
|
