Add a new mansearch.h interface, which replaces apropos_db.c

This is a much more minimal interface that stuffs all operations into
a single function.
It uses sqlite3 and ohash.

1 files changed, 436 insertions, 0 deletions

diff --git a/mansearch.c b/mansearch.c
new file mode 100644
index 00000000..d752b917
--- /dev/null
+++ b/mansearch.c
@@ -0,0 +1,436 @@
+/*	$Id$ */
+/*
+ * Copyright (c) 2012 Kristaps Dzonsons <kristaps@bsd.lv>
+ *
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include <sys/param.h>
+
+#include <assert.h>
+#include <fcntl.h>
+#include <getopt.h>
+#include <stdio.h>
+#include <stdint.h>
+#include <stddef.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+#include <ohash.h>
+#include <sqlite3.h>
+
+#include "mandoc.h"
+#include "manpath.h"
+#include "mandocdb.h"
+#include "mansearch.h"
+
+struct	expr {
+	int		 glob; /* is glob? */
+	uint64_t 	 bits; /* type-mask */
+	const char	*v; /* search value */
+	struct expr	*next; /* next in sequence */
+};
+
+struct	match {
+	uint64_t	 id; /* identifier in database */
+	char		*file; /* relative filepath of manpage */
+	char		*desc; /* description of manpage */
+	int		 form; /* 0 == catpage */
+};
+
+struct	type {
+	uint64_t	 bits;
+	const char	*name;
+};
+
+static	const struct type types[] = {
+	{ TYPE_An,  "An" },
+	{ TYPE_Ar,  "Ar" },
+	{ TYPE_At,  "At" },
+	{ TYPE_Bsx, "Bsx" },
+	{ TYPE_Bx,  "Bx" },
+	{ TYPE_Cd,  "Cd" },
+	{ TYPE_Cm,  "Cm" },
+	{ TYPE_Dv,  "Dv" },
+	{ TYPE_Dx,  "Dx" },
+	{ TYPE_Em,  "Em" },
+	{ TYPE_Er,  "Er" },
+	{ TYPE_Ev,  "Ev" },
+	{ TYPE_Fa,  "Fa" },
+	{ TYPE_Fl,  "Fl" },
+	{ TYPE_Fn,  "Fn" },
+	{ TYPE_Fn,  "Fo" },
+	{ TYPE_Ft,  "Ft" },
+	{ TYPE_Fx,  "Fx" },
+	{ TYPE_Ic,  "Ic" },
+	{ TYPE_In,  "In" },
+	{ TYPE_Lb,  "Lb" },
+	{ TYPE_Li,  "Li" },
+	{ TYPE_Lk,  "Lk" },
+	{ TYPE_Ms,  "Ms" },
+	{ TYPE_Mt,  "Mt" },
+	{ TYPE_Nd,  "Nd" },
+	{ TYPE_Nm,  "Nm" },
+	{ TYPE_Nx,  "Nx" },
+	{ TYPE_Ox,  "Ox" },
+	{ TYPE_Pa,  "Pa" },
+	{ TYPE_Rs,  "Rs" },
+	{ TYPE_Sh,  "Sh" },
+	{ TYPE_Ss,  "Ss" },
+	{ TYPE_St,  "St" },
+	{ TYPE_Sy,  "Sy" },
+	{ TYPE_Tn,  "Tn" },
+	{ TYPE_Va,  "Va" },
+	{ TYPE_Va,  "Vt" },
+	{ TYPE_Xr,  "Xr" },
+	{ ~0ULL,    "any" },
+	{ 0ULL, NULL }
+};
+
+static	void		*hash_alloc(size_t, void *);
+static	void		 hash_free(void *, size_t, void *);
+static	void		*hash_halloc(size_t, void *);
+static	struct expr	*exprcomp(int, char *[]);
+static	void		 exprfree(struct expr *);
+static	struct expr	*exprterm(char *);
+static	char		*sql_statement(const struct expr *,
+				const char *, const char *);
+
+int
+mansearch(const struct manpaths *paths, 
+		const char *arch, const char *sec,
+		int argc, char *argv[], 
+		struct manpage **res, size_t *sz)
+{
+	int		 fd, rc;
+	int64_t		 id;
+	char		 buf[MAXPATHLEN];
+	char		*sql;
+	struct expr	*e, *ep;
+	sqlite3		*db;
+	sqlite3_stmt	*s;
+	struct match	*mp;
+	struct ohash_info info;
+	struct ohash	 htab;
+	unsigned int	 idx;
+	size_t		 i, j, cur, maxres;
+
+	memset(&info, 0, sizeof(struct ohash_info));
+
+	info.halloc = hash_halloc;
+	info.alloc = hash_alloc;
+	info.hfree = hash_free;
+	info.key_offset = offsetof(struct match, id);
+
+	*sz = 0;
+	sql = NULL;
+	*res = NULL;
+	fd = -1;
+	e = NULL;
+	cur = maxres = 0;
+
+	if (0 == argc)
+		goto out;
+	if (NULL == (e = exprcomp(argc, argv)))
+		goto out;
+
+	/*
+	 * Save a descriptor to the current working directory.
+	 * Since pathnames in the "paths" variable might be relative,
+	 * and we'll be chdir()ing into them, we need to keep a handle
+	 * on our current directory from which to start the chdir().
+	 */
+
+	if (NULL == getcwd(buf, MAXPATHLEN)) {
+		perror(NULL);
+		goto out;
+	} else if (-1 == (fd = open(buf, O_RDONLY, 0))) {
+		perror(buf);
+		goto out;
+	}
+
+	sql = sql_statement(e, arch, sec);
+
+	/*
+	 * Loop over the directories (containing databases) for us to
+	 * search.
+	 * Don't let missing/bad databases/directories phase us.
+	 * In each, try to open the resident database and, if it opens,
+	 * scan it for our match expression.
+	 */
+
+	for (i = 0; i < paths->sz; i++) {
+		if (-1 == fchdir(fd)) {
+			/* FIXME: will return success */
+			perror(buf);
+			free(*res);
+			break;
+		} else if (-1 == chdir(paths->paths[i])) {
+			perror(paths->paths[i]);
+			continue;
+		} 
+
+		rc =  sqlite3_open_v2
+			(MANDOC_DB, &db, SQLITE_OPEN_READONLY, NULL);
+
+		if (SQLITE_OK != rc) {
+			perror(MANDOC_DB);
+			sqlite3_close(db);
+			continue;
+		}
+
+		j = 1;
+		sqlite3_prepare_v2(db, sql, -1, &s, NULL);
+
+		if (NULL != arch)
+			sqlite3_bind_text
+				(s, j++, arch, -1, SQLITE_STATIC);
+		if (NULL != sec)
+			sqlite3_bind_text
+				(s, j++, sec, -1, SQLITE_STATIC);
+
+		for (ep = e; NULL != ep; ep = ep->next) {
+			sqlite3_bind_text
+				(s, j++, ep->v, -1, SQLITE_STATIC);
+			sqlite3_bind_int64
+				(s, j++, ep->bits);
+		}
+
+		memset(&htab, 0, sizeof(struct ohash));
+		ohash_init(&htab, 4, &info);
+
+		/*
+		 * Hash each entry on its [unique] document identifier.
+		 * This is a uint64_t.
+		 * Instead of using a hash function, simply convert the
+		 * uint64_t to a uint32_t, the hash value's type.
+		 * This gives good performance and preserves the
+		 * distribution of buckets in the table.
+		 */
+		while (SQLITE_ROW == sqlite3_step(s)) {
+			id = sqlite3_column_int64(s, 0);
+			idx = ohash_lookup_memory
+				(&htab, (char *)&id, 
+				 sizeof(uint64_t), (uint32_t)id);
+
+			if (NULL != ohash_find(&htab, idx))
+				continue;
+
+			mp = mandoc_calloc(1, sizeof(struct match));
+			mp->id = id;
+			mp->file = mandoc_strdup
+				((char *)sqlite3_column_text(s, 3));
+			mp->desc = mandoc_strdup
+				((char *)sqlite3_column_text(s, 4));
+			mp->form = sqlite3_column_int(s, 5);
+			ohash_insert(&htab, idx, mp);
+		}
+
+		sqlite3_finalize(s);
+		sqlite3_close(db);
+
+		for (mp = ohash_first(&htab, &idx);
+				NULL != mp;
+				mp = ohash_next(&htab, &idx)) {
+			if (cur + 1 > maxres) {
+				maxres += 1024;
+				*res = mandoc_realloc
+					(*res, maxres * sizeof(struct manpage));
+			}
+			strlcpy((*res)[cur].file, 
+				paths->paths[i], MAXPATHLEN);
+			strlcat((*res)[cur].file, "/", MAXPATHLEN);
+			strlcat((*res)[cur].file, mp->file, MAXPATHLEN);
+			(*res)[cur].desc = mp->desc;
+			(*res)[cur].form = mp->form;
+			free(mp->file);
+			free(mp);
+			cur++;
+		}
+		ohash_delete(&htab);
+	}
+out:
+	exprfree(e);
+	if (-1 != fd)
+		close(fd);
+	free(sql);
+	*sz = cur;
+	return(1);
+}
+
+/*
+ * Prepare the search SQL statement.
+ * We search for any of the words specified in our match expression.
+ * We filter the per-doc AND expressions when collecting results.
+ */
+static char *
+sql_statement(const struct expr *e, const char *arch, const char *sec)
+{
+	char		*sql;
+	const char	*glob = "(key GLOB ? AND bits & ?)";
+	const char	*eq = "(key = ? AND bits & ?)";
+	const char	*andarch = "arch = ? AND ";
+	const char	*andsec = "sec = ? AND ";
+	const size_t	 globsz = 27;
+	const size_t	 eqsz = 22;
+	size_t		 sz;
+
+	sql = mandoc_strdup
+		("SELECT docid,bits,key,file,desc,form,sec,arch "
+		 "FROM keys "
+		 "INNER JOIN docs ON docs.id=keys.docid "
+		 "WHERE ");
+	sz = strlen(sql);
+
+	if (NULL != arch) {
+		sz += strlen(andarch) + 1;
+		sql = mandoc_realloc(sql, sz);
+		strlcat(sql, andarch, sz);
+	}
+	if (NULL != sec) {
+		sz += strlen(andsec) + 1;
+		sql = mandoc_realloc(sql, sz);
+		strlcat(sql, andsec, sz);
+	}
+
+	sz += 2;
+	sql = mandoc_realloc(sql, sz);
+	strlcat(sql, "(", sz);
+
+	for ( ; NULL != e; e = e->next) {
+		sz += (e->glob ? globsz : eqsz) + 
+			(NULL == e->next ? 3 : 5);
+		sql = mandoc_realloc(sql, sz);
+		strlcat(sql, e->glob ? glob : eq, sz);
+		strlcat(sql, NULL == e->next ? ");" : " OR ", sz);
+	}
+
+	return(sql);
+}
+
+/*
+ * Compile a set of string tokens into an expression.
+ * Tokens in "argv" are assumed to be individual expression atoms (e.g.,
+ * "(", "foo=bar", etc.).
+ */
+static struct expr *
+exprcomp(int argc, char *argv[])
+{
+	int		 i;
+	struct expr	*first, *next, *cur;
+
+	first = cur = NULL;
+
+	for (i = 0; i < argc; i++) {
+		next = exprterm(argv[i]);
+		if (NULL == next) {
+			exprfree(first);
+			return(NULL);
+		}
+		if (NULL != first) {
+			cur->next = next;
+			cur = next;
+		} else
+			cur = first = next;
+	}
+
+	return(first);
+}
+
+static struct expr *
+exprterm(char *buf)
+{
+	struct expr	*e;
+	char		*key, *v;
+	size_t		 i;
+
+	if ('\0' == *buf)
+		return(NULL);
+
+	e = mandoc_calloc(1, sizeof(struct expr));
+
+	/*
+	 * If no =~ is specified, search with equality over names and
+	 * descriptions.
+	 * If =~ begins the phrase, use name and description fields.
+	 */
+
+	if (NULL == (v = strpbrk(buf, "=~"))) {
+		e->v = buf;
+		e->bits = TYPE_Nm | TYPE_Nd;
+		return(e);
+	} else if (v == buf)
+		e->bits = TYPE_Nm | TYPE_Nd;
+
+	e->glob = '~' == *v;
+	*v++ = '\0';
+	e->v = v;
+
+	/*
+	 * Parse out all possible fields.
+	 * If the field doesn't resolve, bail.
+	 */
+
+	while (NULL != (key = strsep(&buf, ","))) {
+		if ('\0' == *key)
+			continue;
+		i = 0;
+		while (types[i].bits && 
+			strcasecmp(types[i].name, key))
+			i++;
+		if (0 == types[i].bits) {
+			free(e);
+			return(NULL);
+		}
+		e->bits |= types[i].bits;
+	}
+
+	return(e);
+}
+
+static void
+exprfree(struct expr *p)
+{
+	struct expr	*pp;
+
+	while (NULL != p) {
+		pp = p->next;
+		free(p);
+		p = pp;
+	}
+}
+
+static void *
+hash_halloc(size_t sz, void *arg)
+{
+
+	return(mandoc_calloc(sz, 1));
+}
+
+static void *
+hash_alloc(size_t sz, void *arg)
+{
+
+	return(mandoc_malloc(sz));
+}
+
+static void
+hash_free(void *p, size_t sz, void *arg)
+{
+
+	free(p);
+}