src/q.h

#ifndef Q_H
#define Q_H
 
#include <stdio.h>
#include <sys/types.h>
 
/* generously sized rather than exactly right-sized: static storage, not
 * stack, so the cost of headroom is a few kb of bss, not a real
 * constraint -- and getting a size limit wrong fails loudly (readfile's
 * truncation detection, snap_add's overflow die) rather than silently
 * corrupting data. */
#define MAXFILE (1024L * 1024L)
#define MAXKV 256
#define MAXKEY 32
#define MAXVAL 512
#define MAXPATH 1024
#define MAXSNAP (4L * 1024L * 1024L)
#define MAXPATHS 131072
 
struct kv
{
	char key[MAXKEY];
	char val[MAXVAL];
};
 
/* resolved runtime config: the config file's path plus the four values q
 * derives from it (see conf.c's loadcfg). */
struct qcfg
{
	char conf[MAXPATH];
	char prefix[MAXPATH];
	char db[MAXPATH];
	char shell[MAXPATH];
	char pkgs[MAXPATH];
};
 
/* one in-memory snapshot of every path under a prefix. q captures two
 * (before/after an install) and diffs them to learn which files that
 * install added. malloc'd, not static, so the several mb exist only
 * while a command holds the snapshot, not as permanent bss. */
struct snap
{
	char* buf;	/* paths, nul-terminated and contiguous */
	long cap;	/* allocated bytes in buf */
	long len;	/* bytes used in buf */
	long* idx;	/* offset of each path in buf */
	long icap;	/* allocated entries in idx */
	long n;		/* number of paths */
};
 
/* util.c -- base helpers the rest of q depends on. die() always exit()s,
 * but q stays pure c89 (no __attribute__((noreturn)), a gnu/clang
 * extension) -- so every call site adds its own explicit "return;"
 * immediately after die() to close the fall-through path off in plain,
 * portable c89. */
void die(const char* msg);
long readfile(const char* path, char* buf, long max);
long writefile(const char* path, const char* buf, long n);
long bufcat(char* dst, size_t max, size_t* off, const char* str);
long pathjoin(char* dst, size_t max, const char* a, const char* b);
long pathfits(const char* a, const char* b);
long copystr(char* dst, size_t max, const char* src);
 
/* conf.c -- config resolution and recipe-metadata parsing. */
long parseconf(const char* buf, long n, struct kv* kv, long max);
const char* kvget(struct kv* kv, long nkv, const char* key);
void loadcfg(struct qcfg* c);
 
/* runsh.c -- run one recipe's command via "shell -e recipe cmd", with
 * /etc/q.cfg sourced first and Q_PREFIX/Q_DB/Q_PKGS exported; 0 on
 * success, 1 on failure. */
int runrecipe(const struct qcfg* c, const char* recipe, const char* cmd);
 
/* fstree.c -- filesystem-tree operations: walk a prefix into a snapshot
 * (presence only, no type/mtime bookkeeping), plus recursive remove and
 * mkdir -p. */
void walktree(struct snap* s, const char* base, const char* rel);
void rmtree(const char* path);
void makedirs(const char* path);
 
/* snap.c -- snapshot collection, sorting, lookup, and manifest io. */
void snap_init(struct snap* s);
void snap_add(struct snap* s, const char* rel);
void snap_sort(struct snap* s);
long snap_has(const struct snap* s, const char* rel);
const char* snap_path(const struct snap* s, long i);
long snap_readfile(struct snap* s, const char* path);
void snap_writefile(const struct snap* s, const char* path);
void snap_free(struct snap* s);
/* the manifest a package owns after an install/update: every path now
 * present that either was already owned (still there) or appeared during
 * the operation (in after, not before). old must be sorted. */
void manifest_diff(const struct snap* before, const struct snap* after,
    const struct snap* old, struct snap* out);
 
/* db.c -- the installed-package database: <db>/<pkg>/{name,ver,manifest}. */
void db_pkgdir(const char* db, const char* pkg, char* out, size_t max);
long db_has(const char* db, const char* pkg);
void db_install(const char* db, const char* pkg, const char* name,
    const char* ver, const struct snap* manifest);
void db_remove(const char* db, const char* pkg);
long db_list(const char* db, struct kv* out, long max);
 
/* q.c -- cli plumbing. */
void badusage(const char* prog, const char* syntax);
 
#endif