X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~mdw/git/disorder/blobdiff_plain/7c82ecb820073aa894f9b41442fdf910c19accdb..e7eb3a2744aa45179daea235800753d3d1955338:/server/choose.c diff --git a/server/choose.c b/server/choose.c index 4e1b326..a4bf443 100644 --- a/server/choose.c +++ b/server/choose.c @@ -1,21 +1,20 @@ /* * This file is part of DisOrder * Copyright (C) 2008 Richard Kettlewell + * Copyright (C) 2008 Mark Wooding * - * This program is free software; you can redistribute it and/or modify + * This program is free software: you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by - * the Free Software Foundation; either version 2 of the License, or + * the Free Software Foundation, either version 3 of the License, or * (at your option) any later version. - * - * This program is distributed in the hope that it will be useful, but - * WITHOUT ANY WARRANTY; without even the implied warranty of - * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU - * General Public License for more details. - * + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * * You should have received a copy of the GNU General Public License - * along with this program; if not, write to the Free Software - * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 - * USA + * along with this program. If not, see . */ /** @file choose.c * @brief Random track chooser @@ -25,36 +24,9 @@ * deadlock - it just exits and expects the server to try again. */ -#include -#include "types.h" - -#include -#include -#include -#include -#include -#include -#include -#include -#include -#include -#include -#include -#include - -#include "configuration.h" -#include "log.h" -#include "defs.h" -#include "mem.h" -#include "kvp.h" -#include "syscalls.h" -#include "printf.h" -#include "trackdb.h" -#include "trackdb-int.h" -#include "version.h" -#include "trackname.h" -#include "queue.h" -#include "server-queue.h" +#include "disorder-server.h" + +#define BASE_WEIGHT 90000 static DB_TXN *global_tid; @@ -80,7 +52,7 @@ static void help(void) { " --debug, -d Turn on debugging\n" " --[no-]syslog Enable/disable logging to syslog\n" "\n" - "Track choose for DisOrder. Not intended to be run\n" + "Track chooser for DisOrder. Not intended to be run\n" "directly.\n"); xfclose(stdout); exit(0); @@ -120,7 +92,7 @@ static unsigned long compute_weight(const char *track, struct kvp *prefs) { const char *s; char **track_tags; - time_t last, now; + time_t last, now = time(0); /* Reject tracks not in any collection (race between edit config and * rescan) */ @@ -141,7 +113,6 @@ static unsigned long compute_weight(const char *track, /* Reject tracks played within the last 8 hours */ if((s = kvp_get(prefs, "played_time"))) { last = atoll(s); - now = time(0); if(now < last + config->replay_min) return 0; } @@ -171,23 +142,20 @@ static unsigned long compute_weight(const char *track, if((errno == 0 || errno == ERANGE) && n >= 0) return n; } - - return 90000; -} -/** @brief Pick a random integer uniformly from [0, limit) */ -static void random_bytes(unsigned char *buf, size_t n) { - static int fd = -1; - int r; + /* Bias up tracks that were recently added */ + if((s = kvp_get(data, "_noticed"))) { + const time_t noticed = atoll(s); - if(fd < 0) { - if((fd = open("/dev/urandom", O_RDONLY)) < 0) - fatal(errno, "opening /dev/urandom"); + if(noticed + config->new_bias_age < now) + /* Currently we just step up the weight of tracks that are in range. A + * more sophisticated approach would be to linearly decay from new_bias + * down to BASE_WEIGHT over the course of the new_bias_age interval + * starting when the track is added. */ + return config->new_bias; } - if((r = read(fd, buf, n)) < 0) - fatal(errno, "reading /dev/urandom"); - if((size_t)r < n) - fatal(0, "short read from /dev/urandom"); + + return BASE_WEIGHT; } /** @brief Pick a random integer uniformly from [0, limit) */ @@ -196,7 +164,7 @@ static unsigned long long pick_weight(unsigned long long limit) { unsigned long long t, r, slop; int i, nby, nbi; - //info("pick_weight: limit = %llu", limit); + D(("pick_weight: limit = %#016llx", limit)); /* First, decide how many bits of output we actually need; do bytes first * (they're quicker) and then bits. @@ -213,7 +181,7 @@ static unsigned long long pick_weight(unsigned long long limit) { if (t >> 2) { t >>= 2; nbi += 2; } if (t >> 1) { t >>= 1; nbi += 1; } nbi++; - //info("nby = %d; nbi = %d", nby, nbi); + D(("nby = %d; nbi = %d", nby, nbi)); /* Main randomness collection loop. We read a number of bytes from the * randomness source, and glue them together into an integer (dropping @@ -227,14 +195,14 @@ static unsigned long long pick_weight(unsigned long long limit) { * limit > 0; if r < slop then we try again, otherwise r - slop is our * winner. */ - slop = (2 << (nbi - 1)) - limit; + slop = ((unsigned long long)2 << (nbi - 1)) - limit; m = nbi & 7 ? (1 << (nbi & 7)) - 1 : 0xff; - //info("slop = %llu", slop); - //info("m = 0x%02x", m); + D(("slop = %#016llx", slop)); + D(("m = 0x%02x", m)); do { /* Actually get some random data. */ - random_bytes(buf, nby); + random_get(buf, nby); /* Clobber the top byte. */ buf[0] &= m; @@ -242,9 +210,10 @@ static unsigned long long pick_weight(unsigned long long limit) { /* Turn it into an integer. */ for (r = 0, i = 0; i < nby; i++) r = (r << 8) | buf[i]; - //info("r = %llu", r); + D(("r = %#016llx", r)); } while (r < slop); + D((" result=%#016llx", r - slop)); return r - slop; } @@ -279,6 +248,7 @@ static int collect_tracks_callback(const char *track, * choose thing i, for 0 <= i < n - 1, is w_i/c_{n-1} (induction * hypothesis); undoing the conditioning gives the desired result. */ + D(("consider %s", track)); if(weight) { total_weight += weight; if (pick_weight(total_weight) < weight) @@ -330,7 +300,7 @@ int main(int argc, char **argv) { trackdb_commit_transaction(global_tid); trackdb_close(); trackdb_deinit(); - //info("ntracks=%ld total_weight=%lld", ntracks, total_weight); + D(("ntracks=%ld total_weight=%lld", ntracks, total_weight)); if(!total_weight) fatal(0, "no tracks match random choice criteria"); if(!winning)