Introduce APIs for splitting/joining strings

This introduces a few new APIs for dealing with strings.
One to split a char * into a char **, another to join a
char ** into a char *, and finally one to free a char **

There is a simple test suite to validate the edge cases
too. No more need to use the horrible strtok_r() API,
or hand-written code for splitting strings.
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>
(cherry picked from commit 76c1fd33)
Signed-off-by: NEric Blake <eblake@redhat.com>

Conflicts:
	tests/Makefile.am - several intermediate tests not backported

.gitignore

@@ -147,6 +147,7 @@
 /tests/virkeyfiletest
 /tests/virnet*test
 /tests/virshtest
+/tests/virstringtest
 /tests/virtimetest
 /tests/viruritest
 /tests/vmx2xmltest

src/Makefile.am

@@ -106,6 +106,7 @@ UTIL_SOURCES =							\
 		util/virnetlink.c util/virnetlink.h		\
 		util/virrandom.h util/virrandom.c		\
 		util/virsocketaddr.h util/virsocketaddr.c \
+		util/virstring.h util/virstring.c \
 		util/virtime.h util/virtime.c \
 		util/viruri.h util/viruri.c
 

src/libvirt_private.syms

@@ -1490,6 +1490,12 @@ virSetErrorLogPriorityFunc;
 virStrerror;
 
 
+# virstring.h
+virStringSplit;
+virStringJoin;
+virStringFreeList;
+
+
 # virtime.h
 virTimeFieldsNow;
 virTimeFieldsNowRaw;

src/util/virstring.c

+/*
+ * Copyright (C) 2012 Red Hat, Inc.
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library 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
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library.  If not, see
+ * <http://www.gnu.org/licenses/>.
+ *
+ * Authors:
+ *     Daniel P. Berrange <berrange@redhat.com>
+ */
+
+#include <config.h>
+
+#include "virstring.h"
+#include "memory.h"
+#include "buf.h"
+#include "virterror_internal.h"
+
+#define VIR_FROM_THIS VIR_FROM_NONE
+
+/*
+ * The following virStringSplit & virStringJoin methods
+ * are derived from g_strsplit / g_strjoin in glib2,
+ * also available under the LGPLv2+ license terms
+ */
+
+/**
+ * virStringSplit:
+ * @string: a string to split
+ * @delim: a string which specifies the places at which to split
+ *     the string. The delimiter is not included in any of the resulting
+ *     strings, unless @max_tokens is reached.
+ * @max_tokens: the maximum number of pieces to split @string into.
+ *     If this is 0, the string is split completely.
+ *
+ * Splits a string into a maximum of @max_tokens pieces, using the given
+ * @delim. If @max_tokens is reached, the remainder of @string is
+ * appended to the last token.
+ *
+ * As a special case, the result of splitting the empty string "" is an empty
+ * vector, not a vector containing a single string. The reason for this
+ * special case is that being able to represent a empty vector is typically
+ * more useful than consistent handling of empty elements. If you do need
+ * to represent empty elements, you'll need to check for the empty string
+ * before calling virStringSplit().
+ *
+ * Return value: a newly-allocated NULL-terminated array of strings. Use
+ *    virStringFreeList() to free it.
+ */
+char **virStringSplit(const char *string,
+                      const char *delim,
+                      size_t max_tokens)
+{
+    char **tokens = NULL;
+    size_t ntokens = 0;
+    size_t maxtokens = 0;
+    const char *remainder = string;
+    char *tmp;
+    size_t i;
+
+    if (max_tokens == 0)
+        max_tokens = INT_MAX;
+
+    tmp = strstr(remainder, delim);
+    if (tmp) {
+        size_t delimlen = strlen(delim);
+
+        while (--max_tokens && tmp) {
+            size_t len = tmp - remainder;
+
+            if (VIR_RESIZE_N(tokens, maxtokens, ntokens, 1) < 0)
+                goto no_memory;
+
+            if (!(tokens[ntokens] = strndup(remainder, len)))
+                goto no_memory;
+            ntokens++;
+            remainder = tmp + delimlen;
+            tmp = strstr(remainder, delim);
+        }
+    }
+    if (*string) {
+        if (VIR_RESIZE_N(tokens, maxtokens, ntokens, 1) < 0)
+            goto no_memory;
+
+        if (!(tokens[ntokens] = strdup(remainder)))
+            goto no_memory;
+        ntokens++;
+    }
+
+    if (VIR_RESIZE_N(tokens, maxtokens, ntokens, 1) < 0)
+        goto no_memory;
+    tokens[ntokens++] = NULL;
+
+    return tokens;
+
+no_memory:
+    virReportOOMError();
+    for (i = 0 ; i < ntokens ; i++)
+        VIR_FREE(tokens[i]);
+    VIR_FREE(tokens);
+    return NULL;
+}
+
+
+/**
+ * virStringJoin:
+ * @strings: a NULL-terminated array of strings to join
+ * @delim: a string to insert between each of the strings
+ *
+ * Joins a number of strings together to form one long string, with the
+ * @delim inserted between each of them. The returned string
+ * should be freed with VIR_FREE().
+ *
+ * Returns: a newly-allocated string containing all of the strings joined
+ *     together, with @delim between them
+ */
+char *virStringJoin(const char **strings,
+                    const char *delim)
+{
+    char *ret;
+    virBuffer buf = VIR_BUFFER_INITIALIZER;
+    while (*strings) {
+        virBufferAdd(&buf, *strings, -1);
+        if (*(strings+1))
+            virBufferAdd(&buf, delim, -1);
+        strings++;
+    }
+    if (virBufferError(&buf)) {
+        virReportOOMError();
+        return NULL;
+    }
+    ret = virBufferContentAndReset(&buf);
+    if (!ret) {
+        if (!(ret = strdup(""))) {
+            virReportOOMError();
+            return NULL;
+        }
+    }
+    return ret;
+}
+
+
+/**
+ * virStringFreeList:
+ * @str_array: a NULL-terminated array of strings to free
+ *
+ * Frees a NULL-terminated array of strings, and the array itself.
+ * If called on a NULL value, virStringFreeList() simply returns.
+ */
+void virStringFreeList(char **strings)
+{
+    char **tmp = strings;
+    while (tmp && *tmp) {
+        VIR_FREE(*tmp);
+        tmp++;
+    }
+    VIR_FREE(strings);
+}

src/util/virstring.h

+/*
+ * Copyright (C) 2007-2012 Red Hat, Inc.
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library 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
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library.  If not, see
+ * <http://www.gnu.org/licenses/>.
+ *
+ * Authors:
+ *     Daniel P. Berrange <berrange@redhat.com>
+ */
+
+#ifndef __VIR_STRING_H__
+# define __VIR_STRING_H__
+
+# include "internal.h"
+
+char **virStringSplit(const char *string,
+                      const char *delim,
+                      size_t max_tokens)
+    ATTRIBUTE_NONNULL(1) ATTRIBUTE_NONNULL(2);
+
+char *virStringJoin(const char **strings,
+                    const char *delim)
+    ATTRIBUTE_NONNULL(1) ATTRIBUTE_NONNULL(2);
+
+void virStringFreeList(char **strings);
+
+#endif /* __VIR_STRING_H__ */

tests/Makefile.am

@@ -100,7 +100,9 @@ test_programs = virshtest sockettest \
 	virhashtest virnetmessagetest virnetsockettest \
 	utiltest virnettlscontexttest shunloadtest \
 	virtimetest viruritest virkeyfiletest \
-	virauthconfigtest
+	virauthconfigtest \
+	virstringtest \
+	$(NULL)
 
 # This is a fake SSH we use from virnetsockettest
 ssh_SOURCES = ssh.c
@@ -485,6 +487,11 @@ virtimetest_SOURCES = \
 virtimetest_CFLAGS = -Dabs_builddir="\"$(abs_builddir)\"" $(AM_CFLAGS)
 virtimetest_LDADD = ../src/libvirt-net-rpc.la $(LDADDS)
 
+virstringtest_SOURCES = \
+	virstringtest.c testutils.h testutils.c
+virstringtest_CFLAGS = -Dabs_builddir="\"$(abs_builddir)\"" $(AM_CFLAGS)
+virstringtest_LDADD = $(LDADDS)
+
 viruritest_SOURCES = \
 	viruritest.c testutils.h testutils.c
 viruritest_CFLAGS = -Dabs_builddir="\"$(abs_builddir)\"" $(AM_CFLAGS)

tests/virstringtest.c

+/*
+ * Copyright (C) 2012 Red Hat, Inc.
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library 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
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library.  If not, see
+ * <http://www.gnu.org/licenses/>.
+ *
+ * Author: Daniel P. Berrange <berrange@redhat.com>
+ */
+
+#include <config.h>
+
+#include <stdlib.h>
+
+#include "testutils.h"
+#include "util.h"
+#include "virterror_internal.h"
+#include "memory.h"
+#include "logging.h"
+
+#include "virstring.h"
+
+#define VIR_FROM_THIS VIR_FROM_NONE
+
+struct testSplitData {
+    const char *string;
+    const char *delim;
+    size_t max_tokens;
+    const char **tokens;
+};
+
+
+struct testJoinData {
+    const char *string;
+    const char *delim;
+    const char **tokens;
+};
+
+static int testSplit(const void *args)
+{
+    const struct testSplitData *data = args;
+    char **got;
+    char **tmp1;
+    const char **tmp2;
+    int ret = -1;
+
+    if (!(got = virStringSplit(data->string, data->delim, data->max_tokens))) {
+        VIR_DEBUG("Got no tokens at all");
+        return -1;
+    }
+
+    tmp1 = got;
+    tmp2 = data->tokens;
+    while (*tmp1 && *tmp2) {
+        if (STRNEQ(*tmp1, *tmp2)) {
+            fprintf(stderr, "Mismatch '%s' vs '%s'\n", *tmp1, *tmp2);
+            goto cleanup;
+        }
+        tmp1++;
+        tmp2++;
+    }
+    if (*tmp1) {
+        fprintf(stderr, "Too many pieces returned\n");
+        goto cleanup;
+    }
+    if (*tmp2) {
+        fprintf(stderr, "Too few pieces returned\n");
+        goto cleanup;
+    }
+
+    ret = 0;
+cleanup:
+    virStringFreeList(got);
+
+    return ret;
+}
+
+
+static int testJoin(const void *args)
+{
+    const struct testJoinData *data = args;
+    char *got;
+    int ret = -1;
+
+    if (!(got = virStringJoin(data->tokens, data->delim))) {
+        VIR_DEBUG("Got no result");
+        return -1;
+    }
+    if (STRNEQ(got, data->string)) {
+        fprintf(stderr, "Mismatch '%s' vs '%s'\n", got, data->string);
+        goto cleanup;
+    }
+
+    ret = 0;
+cleanup:
+    VIR_FREE(got);
+
+    return ret;
+}
+
+
+static int
+mymain(void)
+{
+    int ret = 0;
+
+#define TEST_SPLIT(str, del, max, toks)                                 \
+    do {                                                                \
+        struct testSplitData splitData = {                              \
+            .string = str,                                              \
+            .delim = del,                                               \
+            .max_tokens = max,                                          \
+            .tokens = toks,                                             \
+        };                                                              \
+        struct testJoinData joinData = {                                \
+            .string = str,                                              \
+            .delim = del,                                               \
+            .tokens = toks,                                             \
+        };                                                              \
+        if (virtTestRun("Split " #str, 1, testSplit, &splitData) < 0)   \
+            ret = -1;                                                   \
+        if (virtTestRun("Join " #str, 1, testJoin, &joinData) < 0)      \
+            ret = -1;                                                   \
+    } while (0)
+
+    const char *tokens1[] = { NULL };
+    TEST_SPLIT("", " ", 0, tokens1);
+
+    const char *tokens2[] = { "", "", NULL };
+    TEST_SPLIT(" ", " ", 0, tokens2);
+
+    const char *tokens3[] = { "", "", "", NULL };
+    TEST_SPLIT("  ", " ", 0, tokens3);
+
+    const char *tokens4[] = { "The", "quick", "brown", "fox", NULL };
+    TEST_SPLIT("The quick brown fox", " ", 0, tokens4);
+
+    const char *tokens5[] = { "The quick ", " fox", NULL };
+    TEST_SPLIT("The quick brown fox", "brown", 0, tokens5);
+
+    const char *tokens6[] = { "", "The", "quick", "brown", "fox", NULL };
+    TEST_SPLIT(" The quick brown fox", " ", 0, tokens6);
+
+    const char *tokens7[] = { "The", "quick", "brown", "fox", "", NULL };
+    TEST_SPLIT("The quick brown fox ", " ", 0, tokens7);
+
+
+    return ret==0 ? EXIT_SUCCESS : EXIT_FAILURE;
+}
+
+VIRT_TEST_MAIN(mymain)