Add new pristine subcommand

laumann

Jan 3, 2024, 7:53 PM

ZYBYX2TBKWAKNMPCWT3B7CJRDEO3LOENGOXZF27JGD4UH6YCN25AC

Dependencies

[2] SMB3M6ES change: rework to make more testable
[3] Q7TKZCJP Add initial support for reading the offsets from a (fixed) change
[4] XJ2PEH74 add meson.build
[5] XTKRT6OQ format the codebase
[6] L3HKOF4W wrap vendored zstd seekable in own file, #2
[7] YM2LC6QP wrap vendored blake3 in own file, #2
[8] ZPNA2D42 ani: add functions to locate .pijul
[9] B3XLVPNC Add ani.c and initial Makefile
[*] 67HZZ5HS meson: shuffle lib and exe sources
[*] PEUS54XQ
[*] FB67XX5E add argument parsing setup
[*] ZTDGWUGP add repository structure
[*] DRK7G22J Add header guard to commands.h

Change contents

replacement in meson.build at line 32

[3.14]→[2.10185:10198](∅→∅)

'change.c'

[3.14]

[3.357]

'change.c',
'db.c',
edit in meson.build at line 46

[11.124]

[11.137]

'cmd-pristine.c',
file addition: db.h (----------)

[12.1]

#ifndef ANI_DB_H
#define ANI_DB_H

struct globalheader {
u16 version; // sanakirja version
u8 root; // which page is currently the root page?
u8 nroots; // how many root pages are there?
u32 crc; // CRC of this page
u64 length; // first free page at the end of the file
u64 freedb; // offset of the free list
u64 rcdb; // offset of the RC db
};

void dbrun(char *);

#endif
file addition: db.c (----------)

[12.1]

#include <stdint.h>
#include <stddef.h>
#include <stdio.h>
#include <stdlib.h>
#include <fcntl.h>
#include <unistd.h>
#include <stdbool.h>

#include <sys/mman.h>

#include "common.h"
#include "types.h"
#include "scaffold.h"
#include "db.h"

#define err(msg) \
do { \
perror(msg); \
exit(EXIT_FAILURE); \
} while (0)

static void
dumpbytes(u8 *mem, usize len)
{
usize i;
for (i = 0; i < len; i++) {
printf("%02x ", mem[i]);
}
printf("\n");
}

static void
readglobalheader(u8 *mem, struct globalheader *gh)
{
dumpbytes(mem, sizeof(struct globalheader));

// FIXME: Does not work for big-endian systems
*gh = *((struct globalheader *)mem);
}

static void
printglobalheader(struct globalheader *gh, bool currentroot)
{
printf("version = %u root = %u %s nroots = %u\n", gh->version, gh->root,
currentroot ? "(current)" : "", gh->nroots);
printf("CRC = 0x%04x (%u)\n", gh->crc, gh->crc);
printf("length = %lu (0x%08lx)\n", gh->length, gh->length);
printf("freedb = %lu\n", gh->freedb);
printf("rcdb = %lu\n", gh->rcdb);
}

void
dbrun(char *db)
{
int fd;
u8 *addr;
u8 nroots, curroot;
size i;
struct globalheader gh;

printf("opening %s\n", db);

fd = open(db, O_RDONLY);
if (fd == -1)
err("open");

usize length = 4096;
int prot = PROT_READ; // memory protection; PROT_{EXEC,READ,WRITE,NONE}
int flags = MAP_PRIVATE; // determines visibility
off_t offset = 0;
addr = mmap(NULL, length, prot, flags, fd, offset);
if (addr == MAP_FAILED)
err("mmap");

readglobalheader(addr, &gh);
munmap(addr, length);
nroots = gh.nroots;
curroot = gh.root;

printglobalheader(&gh, curroot == 0);

// for nroots-1 times, read the i << 12'th page
for (i = 1; i < nroots; i++) {
addr = mmap(NULL, length, prot, flags, fd, i << 12);
if (addr == MAP_FAILED)
err("mmap2");
readglobalheader(addr, &gh);
munmap(addr, length);

printglobalheader(&gh, curroot == i);
}

close(fd);
}
edit in commands.h at line 6

[14.423]

[15.40]

int cmd_pristine(int, const char **, struct repository *);
file addition: cmd-pristine.c (----------)

[12.1]

#include <stdint.h>
#include <stddef.h>
#include <unistd.h>
#include <string.h>

#include "common.h"
#include "types.h"
#include "repository.h"
#include "db.h"

static void
formatdbpath(char *dst, const char *repodir)
{
char *p;

p = stpncpy(dst, repodir, PATH_MAX);
*p++ = '/';
p = stpncpy(p, DOTPIJUL, 6);
*p++ = '/';
p = stpncpy(p, "pristine/db", 11);
}

int
cmd_pristine(int argc, char *argv, struct repository *repo)
{
char dbpath[4096] = { 0 };

(void)argc;
(void)argv;

formatdbpath(dbpath, repo->path);

dbrun(dbpath);

return 0;
}
replacement in ani.c at line 18

[3.129]→[3.129:170](∅→∅),[3.170]→[3.3154:3211](∅→∅)

" init Initialize empty repository\n"
" change Show information about a particular change\n";

[3.129]

[3.173]

" init Initialize empty repository\n"
" change Show information about a particular change\n"
" pristine Show information about the repository database\n";
edit in ani.c at line 32

[3.1921]

[13.1297]

{ "pristine", cmd_pristine, NEED_WORK_TREE },