# Mdbfs was written my Matt Heath matt@proweb.co.uk in July 2003
# It was heavily adapted from
# /appl/cmd/dbfs.b
# which contains this :
# Copyright �1999 Vita Nuova Limited. All rights reserved.
# Revisions copyright �2002 Vita Nuova Holdings Limited. All rights reserved.
# I'm not sure what I'm supposed to put here. The Licence says that if I supply a binary I agree to supply the source
# and any derivatative works (i.e. this one) carry the same burden
# /me shrugs and carries on
# on with the show :
# Mdbfs is an extension to dbfs that takes it into the second dimension with both rows & columns
# it mounts the data read only whereas dbfs was read/write.
# Based on my tabfs the idea was that it would consume less memory but with the primary key hashtable
# it actually uses more !
# mind you the trade off is time, it took six hours to run out of 256Mb of memory with the last one
# at least this one has the grace to do it in 30 seconds
# Usage: mdbfs [-a|-b] [-D] [-1] [-p n] [-P] file mountpoint
# -a|-b - after / before
# -D - print each Tmsg/Rmsg
# -1 - use the first line of the file as the column names (otherwise they are numbered)
# -p n - use column number n as the primary key and therefore the name of the directory for each row (otherwise numbered)
# if this column contains duplicates they will still be created but with distinct Qids but the Hashtable will get screwed
# so it's best not to do that, I've not played with that so be it on your own head
# -P - print every cell of the database in qid order, one per line, data is bracketed thus : >%s<
I was using it for debugging but left it in
# file - The file is split into records on each non-empty line using string->unquoted. The number of columns is calculated
# from the first line. If a row contains less they are still included, any extra are discarded
implement Mdbfs;
include "sys.m";
sys: Sys;
Qid: import Sys;
include "draw.m";
include "arg.m";
include "styx.m";
styx: Styx;
Tmsg, Rmsg: import styx;
include "string.m";
str: String;
include "styxservers.m";
styxservers: Styxservers;
Fid, Styxserver, Navigator, Navop: import styxservers;
Enotfound, Eperm, Ebadarg: import styxservers;
include "bufio.m";
bufio: Bufio;
Iobuf: import bufio;
include "hash.m";
hash : Hash;
HashTable, HashVal : import hash;
Record: adt {
id: int; # file number in directory
dirty: int; # modified but not written
vers: int; # version
data: string;
print: fn(r: self ref Record);
qid: fn (r: self ref Record): Sys->Qid;
};
Database: adt {
name: string;
file: ref Iobuf;
records: array of ref Record;
dirty: int;
vers: int;
row_count : int;
first_row_contains_column_names : int;
primary_key_column_index : int;
column_names_string : string;
column_names_hash : ref HashTable;
column_names_array : array of string;
column_count : int;
pk_hash : ref HashTable;
getrec: fn(db: self ref Database): (string, array of string, string);
findrec: fn(db: self ref Database, row, column: int): ref Record;
set_column_names: fn(db: self ref Database, names : string);
set_column_names_to_numbers: fn(db: self ref Database, num : int);
print: fn(db : self ref Database);
};
Mdbfs: module
{
init: fn(nil: ref Draw->Context, nil: list of string);
};
Qroot, Qrow, Qcolumn: con iota;
stderr: ref Sys->FD;
database: ref Database;
user: string;
Eremoved: con "file removed";
progname : con "2dbfs";
rootfiles := array[] of {"/", "data", "src_filename", "column_names"};
usage()
{
sys->fprint(stderr, "Usage: %s [-a|-b] [-D] [-1] [-p n] [-P] file mountpoint\n", progname);
raise "fail:usage";
}
nomod(s: string)
{
sys->fprint(stderr, "%s: can't load %s: %r\n", progname, s);
raise "fail:load";
}
nomem(s : string)
{
sys->fprint(stderr, "%s : can't allocate memory - %s", progname, s);
raise "fail:memory";
}
init(nil: ref Draw->Context, args: list of string)
{
sys = load Sys Sys->PATH;
sys->pctl(Sys->FORKFD|Sys->NEWPGRP, nil);
stderr = sys->fildes(2);
styx = load Styx Styx->PATH;
if(styx == nil)
nomod(Styx->PATH);
styx->init();
styxservers = load Styxservers Styxservers->PATH;
if(styxservers == nil)
nomod(Styxservers->PATH);
styxservers->init(styx);
bufio = load Bufio Bufio->PATH;
if(bufio == nil)
nomod(Bufio->PATH);
str = load String String->PATH;
if(str == nil)
nomod(String->PATH);
hash = load Hash Hash->PATH;
if(hash == nil)
nomod(Hash->PATH);
arg := load Arg Arg->PATH;
if(arg == nil)
nomod(Arg->PATH);
arg->init(args);
flags := Sys->MREPL;
copt := 0;
first_row_contains_column_names := 0;
primary_key_column_index := -1;
print_db := 0;
while((o := arg->opt()) != 0)
case o {
'a' => flags = Sys->MAFTER;
'b' => flags = Sys->MBEFORE;
'D' => styxservers->traceset(1);
'P' => print_db = 1;
'1' => first_row_contains_column_names = 1;
'p' => primary_key_column_index = int arg->arg();
* => usage();
}
args = arg->argv();
arg = nil;
if(len args != 2)
usage();
file := hd args;
args = tl args;
mountpt := hd args;
df := bufio->open(file, Sys->OREAD);
if(df == nil){
sys->fprint(stderr, "%s: can't open %s: %r\n", progname, file);
raise "fail:open";
}
(db, err) := dbread(ref Database(file, df, nil, 0, 0, 0, first_row_contains_column_names, primary_key_column_index, nil, nil, nil, 0, nil));
if(db == nil){
sys->fprint(stderr, "%s: can't read %s: %s\n", progname, file, err);
raise "fail:dbread";
}
db.file = nil;
database = db;
sys->pctl(Sys->FORKFD, nil);
user = rf("/dev/user");
if(user == nil)
user = "inferno";
fds := array[2] of ref Sys->FD;
if(sys->pipe(fds) < 0){
sys->fprint(stderr, "%s: can't create pipe: %r\n", progname);
raise "fail:pipe";
}
navops := chan of ref Navop;
spawn navigator(navops);
(tchan, srv) := Styxserver.new(fds[0], Navigator.new(navops), big Qroot);
fds[0] = nil;
pidc := chan of int;
spawn serveloop(tchan, srv, pidc, navops);
<-pidc;
if (print_db)
db.print();
if(sys->mount(fds[1], nil, mountpt, flags, nil) < 0) {
sys->fprint(stderr, "%s: mount failed: %r\n", progname);
raise "fail:mount";
}
}
rf(f: string): string
{
fd := sys->open(f, Sys->OREAD);
if(fd == nil)
return nil;
b := array[Sys->NAMEMAX] of byte;
n := sys->read(fd, b, len b);
if(n < 0)
return nil;
return string b[0:n];
}
dbread(db: ref Database): (ref Database, string)
{
db.file.seek(big 0, Sys->SEEKSTART);
rl: list of array of string;
(data, r, err) := db.getrec();
if(err != nil)
return (nil, err);
if(db.first_row_contains_column_names == 1) {
db.set_column_names(data);
(nil, r, err) = db.getrec();
if(err != nil)
return (nil, err);
} else
db.set_column_names_to_numbers(len r);
rl = r :: rl;
db.row_count = 1;
if(db.column_count < 1)
return (nil, "need at least one column name");
for(;;){
(nil, r, err) = db.getrec();
if(err != nil)
return (nil, err);
if(r == nil)
break;
rl = r :: rl;
db.row_count++;
}
record_count := db.row_count * db.column_count;
db.records = array[record_count] of ref Record;
db.pk_hash = hash->new(record_count);
row_num := db.row_count -1;
pk_value : string;
for(; rl != nil; rl = tl rl) {
r = hd rl;
if(db.primary_key_column_index < 0)
pk_value = sys->sprint("%d", row_num);
else
if (len r < db.column_count)
pk_value = sys->sprint("!%d!", row_num);
else
pk_value = r[db.primary_key_column_index];
db.pk_hash.insert(pk_value, HashVal(row_num--, 0.0, nil));
for (column_count := db.column_count - 1; column_count >= 0; column_count--) {
rec := ref Record(--record_count, 0, 0, r[column_count]);
db.records[record_count] = rec;
}
}
return (db, nil);
}
Database.getrec(db: self ref Database): (string, array of string, string)
{
data := db.file.gets('\n');
if(data == nil)
return (nil, nil, nil); # BUG: distinguish i/o error from EOF? - nah
(data, nil) = str->splitl(data, "\n");
if(data == "")
return db.getrec(); # skip blank lines
return (data, list_to_array(str->unquoted(data)), nil);
}
Database.findrec(db: self ref Database, row, column: int): ref Record
{
a := db.records[row].data[column];
return nil;
}
Database.set_column_names(db: self ref Database, names : string)
{
uq := str->unquoted(names);
db.column_names_hash = list_to_hash(uq);
db.column_names_array = list_to_array(uq);
db.column_names_string = names;
db.column_count = len db.column_names_array;
}
Database.set_column_names_to_numbers(db: self ref Database, num : int)
{
namestring := sys->sprint("%d", 0);
for(i:=1; i < num; i++)
namestring += sys->sprint(" %d", i);
db.set_column_names(namestring);
}
Database.print(db: self ref Database)
{
record_count := len db.records;
for( i:=0; i < record_count; i++)
db.records[i].print();
}
Record.qid(r: self ref Record): Sys->Qid
{
return Sys->Qid(QPATH(r.id, Qcolumn), r.vers, Sys->QTFILE);
}
Record.print(r: self ref Record)
{
sys->fprint(stderr, "id: %6d qid: %16.16bx data: >%s<\n", r.id, r.qid().path, r.data);
}
serveloop(tchan: chan of ref Tmsg, srv: ref Styxserver, pidc: chan of int, navops: chan of ref Navop)
{
pidc <-= sys->pctl(Sys->FORKNS|Sys->NEWFD, 1::2::srv.fd.fd::nil);
Serve:
while((gm := <-tchan) != nil){
pick m := gm {
Readerror =>
sys->fprint(stderr, "%s: fatal read error: %s\n", progname, m.error);
break Serve;
Read =>
(c, err) := srv.canread(m);
if(c == nil){
srv.reply(ref Rmsg.Error(m.tag, err));
break;
}
if(c.qtype & Sys->QTDIR){
srv.read(m); # does readdir
break;
}
case TYPE(c.path) {
Qroot =>
case FILENO(c.path) {
2 => srv.reply(styxservers->readstr(m, database.name));
3 => srv.reply(styxservers->readstr(m, database.column_names_string));
* => srv.default(gm);
}
Qcolumn =>
rec_index := FILENO(c.path);
if (rec_index < len database.records)
srv.reply(styxservers->readstr(m, database.records[rec_index].data));
else
srv.default(gm);
* =>
srv.default(gm);
}
Write =>
# nothing writable atm.
(c, merr) := srv.canwrite(m);
if(c == nil){
srv.reply(ref Rmsg.Error(m.tag, merr));
break;
}
case TYPE(c.path) {
Qroot =>
case FILENO(c.path) {
# 2 => srv.reply(styxservers->readstr(m, database.name));
# 3 => srv.reply(styxservers->readstr(m, database.column_names_string));
* =>
srv.default(gm);
}
}
Clunk =>
srv.clunk(m);
* =>
srv.default(gm);
}
}
navops <-= nil; # shut down navigator
}
dir(qid: Sys->Qid, name: string, length: big, uid: string, perm: int): ref Sys->Dir
{
d := ref sys->zerodir;
d.qid = qid;
if(qid.qtype & Sys->QTDIR)
perm |= Sys->DMDIR;
d.mode = perm;
d.name = name;
d.uid = uid;
d.gid = uid;
d.length = length;
return d;
}
dirgen(p: big): (ref Sys->Dir, string)
{
file_index := FILENO(p) ;
case TYPE(p) {
Qroot =>
case file_index {
0 =>
qid := Qid(QPATH(file_index, Qroot), database.vers, Sys->QTDIR);
return (dir(qid, "/", big 0, user, 8r700), nil);
1 =>
qid := Qid(QPATH(file_index, Qroot), database.vers, Sys->QTDIR);
return (dir(qid, "data", big 0, user, 8r555), nil);
* =>
if (file_index < len rootfiles) {
qid := Qid(QPATH(file_index, Qroot), database.vers, Sys->QTFILE);
return (dir(qid, rootfiles[file_index], big 0, user, 8r666), nil);
}
}
Qrow =>
pk_value : string;
if (database.primary_key_column_index < 0) {
pk_value = sys->sprint("%d", file_index);
} else {
cell := file_index * database.column_count + database.primary_key_column_index;
if (cell < len database.records)
pk_value = database.records[cell].data;
}
if (pk_value != nil) {
qid := Qid(QPATH(file_index, Qrow), database.vers, Sys->QTDIR);
return (dir(qid, pk_value, big 0, user, 8r555), nil);
}
Qcolumn =>
column_number := file_index % database.column_count;
if (file_index < len database.records)
return (dir(database.records[file_index].qid(), database.column_names_array[column_number], big 0, user, 8r444), nil);
}
return (nil, Enotfound);
}
navigator(navops: chan of ref Navop)
{
while((m := <-navops) != nil){
pick n := m {
Stat =>
n.reply <-= dirgen(n.path);
Walk =>
case (TYPE(n.path)) {
Qroot =>
case FILENO(n.path) {
0 =>
case n.name {
"data" => n.reply <-= dirgen(QPATH(1, Qroot));
"src_filename" => n.reply <-= dirgen(QPATH(2, Qroot));
"column_names" => n.reply <-= dirgen(QPATH(3, Qroot));
* => n.reply <-= (nil, Enotfound);
}
1 =>
pk := database.pk_hash.find(n.name);
if(pk == nil) {
n.reply <-= (nil, Enotfound);
continue;
}
n.path = QPATH(pk.i, Qrow);
n.reply <-= dirgen(n.path);
* =>
n.reply <-= (nil, "not a directory");
}
Qrow =>
row_index := FILENO(n.path);
column_hashval := database.column_names_hash.find(n.name);
if(column_hashval == nil) {
n.reply <-= (nil, Enotfound);
continue;
}
n.path = QPATH(column_hashval.i + database.column_count * row_index, Qcolumn);
n.reply <-= dirgen(n.path);
* =>
n.reply <-= (nil, "not a directory");
}
Readdir =>
case (TYPE(n.path)) {
Qroot =>
case FILENO(n.path) {
0 =>
for(i := n.offset; --n.count >= 0 && i < len rootfiles; i++)
n.reply <-= dirgen(QPATH(i,Qroot));
1 =>
for(i := n.offset; --n.count >= 0 && i < database.row_count ; i++)
n.reply <-= dirgen(QPATH(i,Qrow));
}
n.reply <-= (nil, nil);
Qrow =>
i_start := FILENO(n.path) * database.column_count;
for(i := n.offset; --n.count >= 0 && i < database.column_count ; i++)
n.reply <-= dirgen(QPATH(i_start++, Qcolumn));
n.reply <-= (nil, nil);
* =>
n.reply <-= (nil, "not a directory");
}
}
}
}
QPATH(index, qtype: int): big
{
bigi := big index;
bigi = bigi << 32;
return bigi | big qtype;
}
TYPE(path: big): int
{
return int path;
}
FILENO(path: big) : int
{
return int (path >> 32) ;
}
list_to_array(lizt : list of string) : array of string
{
list_length := len lizt;
hooray := array[list_length] of string;
for(i := 0; i < list_length ; i++) {
hooray[i] = hd lizt;
lizt = tl lizt;
}
return hooray;
}
list_to_hash(lizt : list of string) : ref HashTable
{
list_length := len lizt;
hsh := hash->new(list_length);
j := 0;
for(i := list_length - 1; i > -1 ; i--) {
v := HashVal(j++, 0.0, nil);
hsh.insert(hd lizt, v);
lizt = tl lizt;
}
return hsh;
}
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