ref: c116550e6a41572796e4db65e4f6acbcb3d9d6f8
dir: /appl/acme/file.b/
implement Filem;
include "common.m";
sys : Sys;
dat : Dat;
utils : Utils;
buffm : Bufferm;
textm : Textm;
editlog: Editlog;
FALSE, TRUE, XXX, Delete, Insert, Filename, BUFSIZE, Astring : import Dat;
Buffer, newbuffer : import buffm;
Text : import textm;
error : import utils;
init(mods : ref Dat->Mods)
{
sys = mods.sys;
dat = mods.dat;
utils = mods.utils;
buffm = mods.bufferm;
textm = mods.textm;
editlog = mods.editlog;
}
#
# Structure of Undo list:
# The Undo structure follows any associated data, so the list
# can be read backwards: read the structure, then read whatever
# data is associated (insert string, file name) and precedes it.
# The structure includes the previous value of the modify bit
# and a sequence number; successive Undo structures with the
# same sequence number represent simultaneous changes.
#
Undo : adt
{
typex : int; # Delete, Insert, Filename
mod : int; # modify bit
seq : int; # sequence number
p0 : int; # location of change (unused in f)
n : int; # # runes in string or file name
};
Undosize : con 8;
SHM : con 16rffff;
undotostr(t, m, s, p, n : int) : string
{
a := "01234567";
a[0] = t;
a[1] = m;
a[2] = s&SHM;
a[3] = (s>>16)&SHM;
a[4] = p&SHM;
a[5] = (p>>16)&SHM;
a[6] = n&SHM;
a[7] = (n>>16)&SHM;
return a;
}
strtoundo(s: string): Undo
{
u: Undo;
u.typex = s[0];
u.mod = s[1];
u.seq = s[2]|(s[3]<<16);
u.p0 = s[4]|(s[5]<<16);
u.n = s[6]|(s[7]<<16);
return u;
}
nullfile : File;
File.addtext(f : self ref File, t : ref Text) : ref File
{
if(f == nil) {
f = ref nullfile;
f.buf = newbuffer();
f.delta = newbuffer();
f.epsilon = newbuffer();
f.ntext = 0;
f.unread = TRUE;
}
oft := f.text;
f.text = array[f.ntext+1] of ref Text;
f.text[0:] = oft[0:f.ntext];
oft = nil;
f.text[f.ntext++] = t;
f.curtext = t;
return f;
}
File.deltext(f : self ref File, t : ref Text)
{
i : int;
for(i=0; i<f.ntext; i++)
if(f.text[i] == t)
break;
if (i == f.ntext)
error("can't find text in File.deltext");
f.ntext--;
if(f.ntext == 0){
f.close();
return;
}
f.text[i:] = f.text[i+1:f.ntext+1];
if(f.curtext == t)
f.curtext = f.text[0];
}
File.insert(f : self ref File, p0 : int, s : string, ns : int)
{
if (p0 > f.buf.nc)
error("bad assert in File.insert");
if(f.seq > 0)
f.uninsert(f.delta, p0, ns);
f.buf.insert(p0, s, ns);
if(ns)
f.mod = TRUE;
}
File.uninsert(f : self ref File, delta : ref Buffer, p0 : int, ns : int)
{
# undo an insertion by deleting
a := undotostr(Delete, f.mod, f.seq, p0, ns);
delta.insert(delta.nc, a, Undosize);
}
File.delete(f : self ref File, p0 : int, p1 : int)
{
if (p0>p1 || p0>f.buf.nc || p1>f.buf.nc)
error("bad assert in File.delete");
if(f.seq > 0)
f.undelete(f.delta, p0, p1);
f.buf.delete(p0, p1);
if(p1 > p0)
f.mod = TRUE;
}
File.undelete(f : self ref File, delta : ref Buffer, p0 : int, p1 : int)
{
buf : ref Astring;
i, n : int;
# undo a deletion by inserting
a := undotostr(Insert, f.mod, f.seq, p0, p1-p0);
m := p1-p0;
if(m > BUFSIZE)
m = BUFSIZE;
buf = utils->stralloc(m);
for(i=p0; i<p1; i+=n){
n = p1 - i;
if(n > BUFSIZE)
n = BUFSIZE;
f.buf.read(i, buf, 0, n);
delta.insert(delta.nc, buf.s, n);
}
utils->strfree(buf);
buf = nil;
delta.insert(delta.nc, a, Undosize);
}
File.setname(f : self ref File, name : string, n : int)
{
if(f.seq > 0)
f.unsetname(f.delta);
f.name = name[0:n];
f.unread = TRUE;
}
File.unsetname(f : self ref File, delta : ref Buffer)
{
# undo a file name change by restoring old name
a := undotostr(Filename, f.mod, f.seq, 0, len f.name);
if(f.name != nil)
delta.insert(delta.nc, f.name, len f.name);
delta.insert(delta.nc, a, Undosize);
}
File.loadx(f : self ref File, p0 : int, fd : ref Sys->FD) : int
{
if(f.seq > 0)
error("undo in file.load unimplemented");
return f.buf.loadx(p0, fd);
}
File.undo(f : self ref File, isundo : int, q0 : int, q1 : int) : (int, int)
{
buf : ref Astring;
i, j, n, up : int;
stop : int;
delta, epsilon : ref Buffer;
u : Undo;
a := utils->stralloc(Undosize);
if(isundo){
# undo; reverse delta onto epsilon, seq decreases
delta = f.delta;
epsilon = f.epsilon;
stop = f.seq;
}else{
# redo; reverse epsilon onto delta, seq increases
delta = f.epsilon;
epsilon = f.delta;
stop = 0; # don't know yet
}
buf = utils->stralloc(BUFSIZE);
while(delta.nc > 0){
up = delta.nc-Undosize;
delta.read(up, a, 0, Undosize);
u = strtoundo(a.s);
if(isundo){
if(u.seq < stop){
f.seq = u.seq;
utils->strfree(buf);
utils->strfree(a);
return (q0, q1);
}
}else{
if(stop == 0)
stop = u.seq;
if(u.seq > stop){
utils->strfree(buf);
utils->strfree(a);
return (q0, q1);
}
}
case(u.typex){
Delete =>
f.seq = u.seq;
f.undelete(epsilon, u.p0, u.p0+u.n);
f.mod = u.mod;
f.buf.delete(u.p0, u.p0+u.n);
for(j=0; j<f.ntext; j++)
f.text[j].delete(u.p0, u.p0+u.n, FALSE);
q0 = u.p0;
q1 = u.p0;
Insert =>
f.seq = u.seq;
f.uninsert(epsilon, u.p0, u.n);
f.mod = u.mod;
up -= u.n;
# buf = utils->stralloc(BUFSIZE);
for(i=0; i<u.n; i+=n){
n = u.n - i;
if(n > BUFSIZE)
n = BUFSIZE;
delta.read(up+i, buf, 0, n);
f.buf.insert(u.p0+i, buf.s, n);
for(j=0; j<f.ntext; j++)
f.text[j].insert(u.p0+i, buf.s, n, FALSE, 0);
}
# utils->strfree(buf);
# buf = nil;
q0 = u.p0;
q1 = u.p0+u.n;
Filename =>
f.seq = u.seq;
f.unsetname(epsilon);
f.mod = u.mod;
up -= u.n;
f.name = nil;
if(u.n == 0)
f.name = nil;
else {
fn0 := utils->stralloc(u.n);
delta.read(up, fn0, 0, u.n);
f.name = fn0.s;
utils->strfree(fn0);
fn0 = nil;
}
* =>
error(sys->sprint("undo: 0x%ux", u.typex));
error("");
}
delta.delete(up, delta.nc);
}
utils->strfree(buf);
utils->strfree(a);
buf = nil;
if(isundo)
f.seq = 0;
return (q0, q1);
}
File.reset(f : self ref File)
{
f.delta.reset();
f.epsilon.reset();
f.seq = 0;
}
File.close(f : self ref File)
{
f.name = nil;
f.ntext = 0;
f.text = nil;
f.buf.close();
f.delta.close();
f.epsilon.close();
editlog->elogclose(f);
f = nil;
}
File.mark(f : self ref File)
{
if(f.epsilon.nc)
f.epsilon.delete(0, f.epsilon.nc);
f.seq = dat->seq;
}
File.redoseq(f : self ref File): int
{
u: Undo;
delta: ref Buffer;
delta = f.epsilon;
if(delta.nc == 0)
return ~0;
buf := utils->stralloc(Undosize);
delta.read(delta.nc-Undosize, buf, 0, Undosize);
u = strtoundo(buf.s);
utils->strfree(buf);
return u.seq;
}