Merge pull request #287 from commodo/json_pointer_va_args

json_pointer: extend setter & getter with printf() style arguments

CMakeLists.txt

@@ -36,6 +36,8 @@ set(JSON_C_HEADERS
     ./json_util.h
     ./linkhash.h
     ./math_compat.h
+    ./strdup_compat.h
+    ./vasprintf_compat.h
     ./printbuf.h
     ./random_seed.h
 )

Makefile.am

@@ -32,6 +32,8 @@ libjson_cinclude_HEADERS = \
 	json_visit.h \
 	linkhash.h \
 	math_compat.h \
+	strdup_compat.h \
+	vasprintf_compat.h \
 	printbuf.h \
 	random_seed.h
 

json-c.vcxproj

@@ -151,6 +151,8 @@ copy json_config.h.win32 json_config.h
     <ClInclude Include="json_util.h" />
     <ClInclude Include="linkhash.h" />
     <ClInclude Include="math_compat.h" />
+    <ClInclude Include="strdup_compat.h" />
+    <ClInclude Include="vasprintf_compat.h" />
     <ClInclude Include="printbuf.h" />
     <ClInclude Include="random_seed.h" />
   </ItemGroup>
@@ -164,4 +166,4 @@ copy json_config.h.win32 json_config.h
   <Import Project="$(VCTargetsPath)\Microsoft.Cpp.targets" />
   <ImportGroup Label="ExtensionTargets">
   </ImportGroup>
-</Project>
+</Project>

json-c.vcxproj.filters

@@ -80,6 +80,12 @@
     <ClInclude Include="math_compat.h">
       <Filter>Header Files</Filter>
     </ClInclude>
+    <ClInclude Include="strdup_compat.h">
+      <Filter>Header Files</Filter>
+    </ClInclude>
+    <ClInclude Include="vasprintf_compat.h">
+      <Filter>Header Files</Filter>
+    </ClInclude>
     <ClInclude Include="random_seed.h">
       <Filter>Header Files</Filter>
     </ClInclude>
@@ -93,4 +99,4 @@
     <None Include="README-WIN32.html" />
     <None Include="README.html" />
   </ItemGroup>
-</Project>
+</Project>

json_object.c

@@ -29,13 +29,7 @@
 #include "json_object_private.h"
 #include "json_util.h"
 #include "math_compat.h"
-
-#if !defined(HAVE_STRDUP) && defined(_MSC_VER)
-  /* MSC has the version as _strdup */
-# define strdup _strdup
-#elif !defined(HAVE_STRDUP)
-# error You do not have strdup on your system.
-#endif /* HAVE_STRDUP */
+#include "strdup_compat.h"
 
 #if !defined(HAVE_SNPRINTF) && defined(_MSC_VER)
   /* MSC has the version as _snprintf */

json_pointer.c

@@ -8,6 +8,7 @@
 
 #include "config.h"
 
+#include <stdarg.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <errno.h>
@@ -15,6 +16,8 @@
 #include <ctype.h>
 
 #include "json_pointer.h"
+#include "strdup_compat.h"
+#include "vasprintf_compat.h"
 
 /**
  * JavaScript Object Notation (JSON) Pointer
@@ -159,7 +162,7 @@ static int json_pointer_get_recursive(
 	}
 
 	/* We should be at the end of the recursion here */
-    if (value)
+	if (value)
 		*value = obj;
 
 	return 0;
@@ -192,6 +195,37 @@ int json_pointer_get(struct json_object *obj, const char *path, struct json_obje
 	return rc;
 }
 
+int json_pointer_getf(struct json_object *obj, struct json_object **res, const char *path_fmt, ...)
+{
+	char *path_copy = NULL;
+	int rc = 0;
+	va_list args;
+
+	if (!obj || !path_fmt) {
+		errno = EINVAL;
+		return -1;
+	}
+
+	va_start(args, path_fmt);
+	rc = vasprintf(&path_copy, path_fmt, args);
+	va_end(args);
+
+	if (rc < 0)
+		return rc;
+
+	if (path_copy[0] == '\0') {
+		if (res)
+			*res = obj;
+		goto out;
+	}
+
+	rc = json_pointer_get_recursive(obj, path_copy, res);
+out:
+	free(path_copy);
+
+	return rc;
+}
+
 int json_pointer_set(struct json_object **obj, const char *path, struct json_object *value)
 {
 	const char *endp;
@@ -237,3 +271,56 @@ int json_pointer_set(struct json_object **obj, const char *path, struct json_obj
 	return json_pointer_set_single_path(set, endp, value);
 }
 
+int json_pointer_setf(struct json_object **obj, struct json_object *value, const char *path_fmt, ...)
+{
+	char *endp;
+	char *path_copy = NULL;
+	struct json_object *set = NULL;
+	va_list args;
+	int rc = 0;
+
+	if (!obj || !path_fmt) {
+		errno = EINVAL;
+		return -1;
+	}
+
+	/* pass a working copy to the recursive call */
+	va_start(args, path_fmt);
+	rc = vasprintf(&path_copy, path_fmt, args);
+	va_end(args);
+
+	if (rc < 0)
+		return rc;
+
+	if (path_copy[0] == '\0') {
+		json_object_put(*obj);
+		*obj = value;
+		goto out;
+	}
+
+	if (path_copy[0] != '/') {
+		errno = EINVAL;
+		rc = -1;
+		goto out;
+	}
+
+	/* If there's only 1 level to set, stop here */
+	if ((endp = strrchr(path_copy, '/')) == path_copy) {
+		set = *obj;
+		goto set_single_path;
+	}
+
+	*endp = '\0';
+	rc = json_pointer_get_recursive(*obj, path_copy, &set);
+
+	if (rc)
+		goto out;
+
+set_single_path:
+	endp++;
+	rc = json_pointer_set_single_path(set, endp, value);
+out:
+	free(path_copy);
+	return rc;
+}
+

json_pointer.h

@@ -27,6 +27,11 @@ extern "C" {
  * Internally, this is equivalent to doing a series of 'json_object_object_get()'
  * and 'json_object_array_get_idx()' along the given 'path'.
  *
+ * Note that the 'path' string supports 'printf()' type arguments, so, whatever
+ * is added after the 'res' param will be treated as an argument for 'path'
+ * Example: json_pointer_get(obj, "/foo/%d/%s", &res, 0, bar)
+ * This means, that you need to escape '%' with '%%' (just like in printf())
+ *
  * @param obj the json_object instance/tree from where to retrieve sub-objects
  * @param path a (RFC6901) string notation for the sub-object to retrieve
  * @param res a pointer where to store a reference to the json_object
@@ -36,6 +41,24 @@ extern "C" {
  */
 int json_pointer_get(struct json_object *obj, const char *path, struct json_object **res);
 
+/**
+ * This is a variant of 'json_pointer_get()' that supports printf() style arguments.
+ *
+ * Example: json_pointer_getf(obj, res, "/foo/%d/%s", 0, bak)
+ * This also means that you need to escape '%' with '%%' (just like in printf())
+ *
+ * Please take into consideration all recommended 'printf()' format security
+ * aspects when using this function.
+ *
+ * @param obj the json_object instance/tree to which to add a sub-object
+ * @param res a pointer where to store a reference to the json_object
+ *              associated with the given path
+ * @param path_fmt a printf() style format for the path
+ *
+ * @return negative if an error (or not found), or 0 if succeeded
+ */
+int json_pointer_getf(struct json_object *obj, struct json_object **res, const char *path_fmt, ...);
+
 /**
  * Sets JSON object 'value' in the 'obj' tree at the location specified
  * by the 'path'. 'path' is JSON pointer notation as defined in RFC 6901
@@ -54,6 +77,11 @@ int json_pointer_get(struct json_object *obj, const char *path, struct json_obje
  * That also implies that 'json_pointer_set()' does not do any refcount incrementing.
  * (Just that single decrement that was mentioned above).
  *
+ * Note that the 'path' string supports 'printf()' type arguments, so, whatever
+ * is added after the 'value' param will be treated as an argument for 'path'
+ * Example: json_pointer_set(obj, "/foo/%d/%s", value, 0, bak)
+ * This means, that you need to escape '%' with '%%' (just like in printf())
+ *
  * @param obj the json_object instance/tree to which to add a sub-object
  * @param path a (RFC6901) string notation for the sub-object to set in the tree
  * @param value object to set at path
@@ -62,6 +90,24 @@ int json_pointer_get(struct json_object *obj, const char *path, struct json_obje
  */
 int json_pointer_set(struct json_object **obj, const char *path, struct json_object *value);
 
+/**
+ * This is a variant of 'json_pointer_set()' that supports printf() style arguments.
+ *
+ * Example: json_pointer_setf(obj, value, "/foo/%d/%s", 0, bak)
+ * This also means that you need to escape '%' with '%%' (just like in printf())
+ *
+ * Please take into consideration all recommended 'printf()' format security
+ * aspects when using this function.
+ *
+ * @param obj the json_object instance/tree to which to add a sub-object
+ * @param value object to set at path
+ * @param path_fmt a printf() style format for the path
+ *
+ * @return negative if an error (or not found), or 0 if succeeded
+ */
+int json_pointer_setf(struct json_object **obj, struct json_object *value, const char *path_fmt, ...);
+
+
 #ifdef __cplusplus
 }
 #endif

json_tokener.c

@@ -31,6 +31,7 @@
 #include "json_object.h"
 #include "json_tokener.h"
 #include "json_util.h"
+#include "strdup_compat.h"
 
 #ifdef HAVE_LOCALE_H
 #include <locale.h>
@@ -41,13 +42,6 @@
 
 #define jt_hexdigit(x) (((x) <= '9') ? (x) - '0' : ((x) & 7) + 9)
 
-#if !HAVE_STRDUP && defined(_MSC_VER)
-  /* MSC has the version as _strdup */
-# define strdup _strdup
-#elif !HAVE_STRDUP
-# error You do not have strdup on your system.
-#endif /* HAVE_STRDUP */
-
 #if !HAVE_STRNCASECMP && defined(_MSC_VER)
   /* MSC has the version as _strnicmp */
 # define strncasecmp _strnicmp

printbuf.c

@@ -27,6 +27,7 @@
 
 #include "debug.h"
 #include "printbuf.h"
+#include "vasprintf_compat.h"
 
 static int printbuf_extend(struct printbuf *p, int min_size);
 
@@ -110,47 +111,6 @@ int printbuf_memset(struct printbuf *pb, int offset, int charvalue, int len)
 	return 0;
 }
 
-#if !defined(HAVE_VSNPRINTF) && defined(_MSC_VER)
-# define vsnprintf _vsnprintf
-#elif !defined(HAVE_VSNPRINTF) /* !HAVE_VSNPRINTF */
-# error Need vsnprintf!
-#endif /* !HAVE_VSNPRINTF && defined(WIN32) */
-
-#if !defined(HAVE_VASPRINTF)
-/* CAW: compliant version of vasprintf */
-static int vasprintf(char **buf, const char *fmt, va_list ap)
-{
-#ifndef WIN32
-	static char _T_emptybuffer = '\0';
-#endif /* !defined(WIN32) */
-	int chars;
-	char *b;
-
-	if(!buf) { return -1; }
-
-#ifdef WIN32
-	chars = _vscprintf(fmt, ap)+1;
-#else /* !defined(WIN32) */
-	/* CAW: RAWR! We have to hope to god here that vsnprintf doesn't overwrite
-	   our buffer like on some 64bit sun systems.... but hey, its time to move on */
-	chars = vsnprintf(&_T_emptybuffer, 0, fmt, ap)+1;
-	if(chars < 0) { chars *= -1; } /* CAW: old glibc versions have this problem */
-#endif /* defined(WIN32) */
-
-	b = (char*)malloc(sizeof(char)*chars);
-	if(!b) { return -1; }
-
-	if((chars = vsprintf(b, fmt, ap)) < 0)
-	{
-		free(b);
-	} else {
-		*buf = b;
-	}
-
-	return chars;
-}
-#endif /* !HAVE_VASPRINTF */
-
 int sprintbuf(struct printbuf *p, const char *msg, ...)
 {
   va_list ap;

strdup_compat.h

@@ -0,0 +1,11 @@
+#ifndef __strdup_compat_h
+#define __strdup_compat_h
+
+#if !defined(HAVE_STRDUP) && defined(_MSC_VER)
+  /* MSC has the version as _strdup */
+# define strdup _strdup
+#elif !defined(HAVE_STRDUP)
+# error You do not have strdup on your system.
+#endif /* HAVE_STRDUP */
+
+#endif

tests/test_json_pointer.c

@@ -132,6 +132,10 @@ static void test_recursion_get()
 	assert(json_object_is_type(jo2, json_type_string));
 	assert(0 == strcmp("1", json_object_get_string(jo2)));
 
+	assert(0 == json_pointer_getf(jo1, &jo2, "/%s/%d/%s/%d/%s", "arr", 0, "obj", 2, "obj2"));
+	assert(json_object_is_type(jo2, json_type_string));
+	assert(0 == strcmp("1", json_object_get_string(jo2)));
+
 	assert(jo1 != NULL);
 	assert(0 == json_pointer_get(jo1, "/obj/obj/obj/0/obj1", &jo2));
 	assert(json_object_is_type(jo2, json_type_int));
@@ -180,6 +184,9 @@ static void test_wrong_inputs_get()
 	assert(0 != json_pointer_get(jo1, "/foo/a", NULL));
 	assert(errno == EINVAL);
 	errno = 0;
+	assert(0 != json_pointer_getf(jo1, NULL, "/%s/a", "foo"));
+	assert(errno == EINVAL);
+	errno = 0;
 	assert(0 != json_pointer_get(jo1, "/foo/-", NULL));
 	assert(errno == EINVAL);
 	errno = 0;
@@ -188,7 +195,10 @@ static void test_wrong_inputs_get()
 	assert(errno == ENOENT);
 	errno = 0;
 	/* Test non-optimized array path */
-	assert(0 != json_pointer_get(jo1, "/foo/22", NULL));
+	assert(0 != json_pointer_getf(jo1, NULL, "%s", "/foo/22"));
+	assert(errno == ENOENT);
+	errno = 0;
+	assert(0 != json_pointer_getf(jo1, NULL, "/%s/%d", "foo", 22));
 	assert(errno == ENOENT);
 	errno = 0;
 	assert(0 != json_pointer_get(jo1, "/foo/-1", NULL));
@@ -220,6 +230,7 @@ static void test_example_set()
 	assert(0 == json_pointer_set(&jo1, "/fud/gaw", jo2)); /* re-using jo2 from above */
 	printf("PASSED - SET - /fug/gaw == [1,2,3]\n");
 	assert(0 == json_pointer_set(&jo1, "/fud/gaw/0", json_object_new_int(0)));
+	assert(0 == json_pointer_setf(&jo1, json_object_new_int(0), "%s%s/%d", "/fud", "/gaw", 0));
 	printf("PASSED - SET - /fug/gaw == [0,2,3]\n");
 	assert(0 == json_pointer_set(&jo1, "/fud/gaw/-", json_object_new_int(4)));
 	printf("PASSED - SET - /fug/gaw == [0,2,3,4]\n");

vasprintf_compat.h

@@ -0,0 +1,45 @@
+#ifndef __vasprintf_compat_h
+#define __vasprintf_compat_h
+
+#if !defined(HAVE_VSNPRINTF) && defined(_MSC_VER)
+# define vsnprintf _vsnprintf
+#elif !defined(HAVE_VSNPRINTF) /* !HAVE_VSNPRINTF */
+# error Need vsnprintf!
+#endif /* !HAVE_VSNPRINTF && defined(WIN32) */
+
+#if !defined(HAVE_VASPRINTF)
+/* CAW: compliant version of vasprintf */
+static int vasprintf(char **buf, const char *fmt, va_list ap)
+{
+#ifndef WIN32
+	static char _T_emptybuffer = '\0';
+#endif /* !defined(WIN32) */
+	int chars;
+	char *b;
+
+	if(!buf) { return -1; }
+
+#ifdef WIN32
+	chars = _vscprintf(fmt, ap)+1;
+#else /* !defined(WIN32) */
+	/* CAW: RAWR! We have to hope to god here that vsnprintf doesn't overwrite
+	   our buffer like on some 64bit sun systems.... but hey, its time to move on */
+	chars = vsnprintf(&_T_emptybuffer, 0, fmt, ap)+1;
+	if(chars < 0) { chars *= -1; } /* CAW: old glibc versions have this problem */
+#endif /* defined(WIN32) */
+
+	b = (char*)malloc(sizeof(char)*chars);
+	if(!b) { return -1; }
+
+	if((chars = vsprintf(b, fmt, ap)) < 0)
+	{
+		free(b);
+	} else {
+		*buf = b;
+	}
+
+	return chars;
+}
+#endif /* !HAVE_VASPRINTF */
+
+#endif /* __vasprintf_compat_h */