Move more channel events to Stasis; move res_json.c to main/json.c.

This patch started out simply as fixing the bouncing tests introduced
in r382685, but required some other changes to give it a decent
implementation.

To fix the bouncing tests, the UserEvent and Newexten AMI events
needed to be refactored to dispatch via Stasis. Dispatching directly
to AMI resulted in those events sometimes getting ahead of the
associated Newchannel events, which would understandably confuse anyone.

I found that instead of creating a zillion different message types and
structures associated with them, it would be preferable to define a
message type that has a channel snapshot and a blob of structured data
with a small bit of additional information. The JSON object model
provides a very nice way of representing structured data, so I went
with that.

 * Move JSON support from res_json.c to main/json.c
   * Made libjansson-dev a required dependency
 * Added an ast_channel_blob message type, which has a channel
   snapshot and JSON blob of data.
 * Changed UserEvent and Newexten events so that they are dispatched
   via ast_channel_blob messages on the channel's topic.
 * Got rid of the ast_channel_varset message; used ast_channel_blob
   instead.
 * Extracted the manager functions converting Stasis channel events to
   AMI events into manager_channel.c.

(issue ASTERISK-21096)
Review: https://reviewboard.asterisk.org/r/2381/


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@383579 65c4cc65-6c06-0410-ace0-fbb531ad65f3

1 files changed, 520 insertions, 0 deletions

diff --git a/main/json.c b/main/json.c
new file mode 100644
index 000000000..f1ebaef60
--- /dev/null
+++ b/main/json.c
@@ -0,0 +1,520 @@
+/*
+ * Asterisk -- An open source telephony toolkit.
+ *
+ * Copyright (C) 2012 - 2013, Digium, Inc.
+ *
+ * David M. Lee, II <dlee@digium.com>
+ *
+ * See http://www.asterisk.org for more information about
+ * the Asterisk project. Please do not directly contact
+ * any of the maintainers of this project for assistance;
+ * the project provides a web site, mailing lists and IRC
+ * channels for your use.
+ *
+ * This program is free software, distributed under the terms of
+ * the GNU General Public License Version 2. See the LICENSE file
+ * at the top of the source tree.
+ */
+
+/*! \file
+ *
+ * \brief JSON abstraction layer.
+ *
+ * This is a very thin wrapper around the Jansson API. For more details on it, see its
+ * docs at http://www.digip.org/jansson/doc/2.4/apiref.html.
+ *
+ * \author David M. Lee, II <dlee@digium.com>
+ */
+
+/*** MODULEINFO
+	<depend>jansson</depend>
+	<support_level>core</support_level>
+ ***/
+
+#include "asterisk.h"
+
+ASTERISK_FILE_VERSION(__FILE__, "$Revision$")
+
+#include "asterisk/json.h"
+#include "asterisk/module.h"
+#include "asterisk/utils.h"
+
+#include <jansson.h>
+
+/*!
+ * \brief Function wrapper around ast_malloc macro.
+ */
+static void *json_malloc(size_t size)
+{
+	return ast_malloc(size);
+}
+
+/*!
+ * \brief Function wrapper around ast_free macro.
+ */
+static void json_free(void *p)
+{
+	ast_free(p);
+}
+
+void ast_json_set_alloc_funcs(void *(*malloc_fn)(size_t), void (*free_fn)(void*))
+{
+	json_set_alloc_funcs(malloc_fn, free_fn);
+}
+
+void ast_json_reset_alloc_funcs(void)
+{
+	json_set_alloc_funcs(json_malloc, json_free);
+}
+
+struct ast_json *ast_json_ref(struct ast_json *json)
+{
+	json_incref((json_t *)json);
+	return json;
+}
+
+void ast_json_unref(struct ast_json *json)
+{
+	json_decref((json_t *)json);
+}
+
+enum ast_json_type ast_json_typeof(const struct ast_json *json)
+{
+	int r = json_typeof((json_t*)json);
+	switch(r) {
+	case JSON_OBJECT: return AST_JSON_OBJECT;
+	case JSON_ARRAY: return AST_JSON_ARRAY;
+	case JSON_STRING: return AST_JSON_STRING;
+	case JSON_INTEGER: return AST_JSON_INTEGER;
+	case JSON_REAL: return AST_JSON_REAL;
+	case JSON_TRUE: return AST_JSON_TRUE;
+	case JSON_FALSE: return AST_JSON_FALSE;
+	case JSON_NULL: return AST_JSON_NULL;
+	}
+	ast_assert(0); /* Unexpect return from json_typeof */
+	return r;
+}
+
+struct ast_json *ast_json_true(void)
+{
+	return (struct ast_json *)json_true();
+}
+
+struct ast_json *ast_json_false(void)
+{
+	return (struct ast_json *)json_false();
+}
+
+struct ast_json *ast_json_boolean(int value)
+{
+#if JANSSON_VERSION_HEX >= 0x020400
+	return (struct ast_json *)json_boolean(value);
+#else
+	return value ? ast_json_true() : ast_json_false();
+#endif
+}
+
+struct ast_json *ast_json_null(void)
+{
+	return (struct ast_json *)json_null();
+}
+
+int ast_json_is_true(const struct ast_json *json)
+{
+	return json_is_true((const json_t *)json);
+}
+
+int ast_json_is_false(const struct ast_json *json)
+{
+	return json_is_false((const json_t *)json);
+}
+
+int ast_json_is_null(const struct ast_json *json)
+{
+	return json_is_null((const json_t *)json);
+}
+
+struct ast_json *ast_json_string_create(const char *value)
+{
+	return (struct ast_json *)json_string(value);
+}
+
+const char *ast_json_string_get(const struct ast_json *string)
+{
+	return json_string_value((json_t *)string);
+}
+
+int ast_json_string_set(struct ast_json *string, const char *value)
+{
+	return json_string_set((json_t *)string, value);
+}
+
+struct ast_json *ast_json_stringf(const char *format, ...)
+{
+	struct ast_json *ret;
+	va_list args;
+	va_start(args, format);
+	ret = ast_json_vstringf(format, args);
+	va_end(args);
+	return ret;
+}
+
+struct ast_json *ast_json_vstringf(const char *format, va_list args)
+{
+	char *str = NULL;
+	json_t *ret = NULL;
+
+	if (format) {
+		int err = vasprintf(&str, format, args);
+		if (err > 0) {
+			ret = json_string(str);
+			free(str);
+		}
+	}
+	return (struct ast_json *)ret;
+}
+
+struct ast_json *ast_json_integer_create(intmax_t value)
+{
+	return (struct ast_json *)json_integer(value);
+}
+
+intmax_t ast_json_integer_get(const struct ast_json *integer)
+{
+	return json_integer_value((json_t *)integer);
+}
+
+int ast_json_integer_set(struct ast_json *integer, intmax_t value)
+{
+	return json_integer_set((json_t *)integer, value);
+}
+
+
+int ast_json_equal(const struct ast_json *lhs, const struct ast_json *rhs)
+{
+	return json_equal((json_t *)lhs, (json_t *)rhs);
+}
+
+struct ast_json *ast_json_array_create(void)
+{
+	return (struct ast_json *)json_array();
+}
+size_t ast_json_array_size(const struct ast_json *array)
+{
+	return json_array_size((json_t *)array);
+}
+struct ast_json *ast_json_array_get(const struct ast_json *array, size_t index)
+{
+	return (struct ast_json *)json_array_get((json_t *)array, index);
+}
+int ast_json_array_set(struct ast_json *array, size_t index, struct ast_json *value)
+{
+	return json_array_set_new((json_t *)array, index, (json_t *)value);
+}
+int ast_json_array_append(struct ast_json *array, struct ast_json *value)
+{
+	return json_array_append_new((json_t *)array, (json_t *)value);
+}
+int ast_json_array_insert(struct ast_json *array, size_t index, struct ast_json *value)
+{
+	return json_array_insert_new((json_t *)array, index, (json_t *)value);
+}
+int ast_json_array_remove(struct ast_json *array, size_t index)
+{
+	return json_array_remove((json_t *)array, index);
+}
+int ast_json_array_clear(struct ast_json *array)
+{
+	return json_array_clear((json_t *)array);
+}
+int ast_json_array_extend(struct ast_json *array, struct ast_json *tail)
+{
+	return json_array_extend((json_t *)array, (json_t *)tail);
+}
+
+struct ast_json *ast_json_object_create(void)
+{
+	return (struct ast_json *)json_object();
+}
+size_t ast_json_object_size(struct ast_json *object)
+{
+	return json_object_size((json_t *)object);
+}
+struct ast_json *ast_json_object_get(struct ast_json *object, const char *key)
+{
+	if (!key) {
+		return NULL;
+	}
+	return (struct ast_json *)json_object_get((json_t *)object, key);
+}
+int ast_json_object_set(struct ast_json *object, const char *key, struct ast_json *value)
+{
+	return json_object_set_new((json_t *)object, key, (json_t *)value);
+}
+int ast_json_object_del(struct ast_json *object, const char *key)
+{
+	return json_object_del((json_t *)object, key);
+}
+int ast_json_object_clear(struct ast_json *object)
+{
+	return json_object_clear((json_t *)object);
+}
+int ast_json_object_update(struct ast_json *object, struct ast_json *other)
+{
+	return json_object_update((json_t *)object, (json_t *)other);
+}
+int ast_json_object_update_existing(struct ast_json *object, struct ast_json *other)
+{
+#if JANSSON_VERSION_HEX >= 0x020300
+	return json_object_update_existing((json_t *)object, (json_t *)other);
+#else
+	struct ast_json_iter *iter = ast_json_object_iter(other);
+	int ret = 0;
+
+	if (object == NULL || other == NULL) {
+		return -1;
+	}
+
+	while (iter != NULL && ret == 0) {
+		const char *key = ast_json_object_iter_key(iter);
+		if (ast_json_object_get(object, key) != NULL) {
+			ret = ast_json_object_set(object, key, ast_json_object_iter_value(iter));
+		}
+		iter = ast_json_object_iter_next(other, iter);
+	}
+	return ret;
+#endif
+}
+int ast_json_object_update_missing(struct ast_json *object, struct ast_json *other)
+{
+#if JANSSON_VERSION_HEX >= 0x020300
+	return json_object_update_missing((json_t *)object, (json_t *)other);
+#else
+	struct ast_json_iter *iter = ast_json_object_iter(other);
+	int ret = 0;
+
+	if (object == NULL || other == NULL) {
+		return -1;
+	}
+
+	while (iter != NULL && ret == 0) {
+		const char *key = ast_json_object_iter_key(iter);
+		if (ast_json_object_get(object, key) == NULL) {
+			ret = ast_json_object_set(object, key, ast_json_object_iter_value(iter));
+		}
+		iter = ast_json_object_iter_next(other, iter);
+	}
+	return ret;
+#endif
+}
+
+struct ast_json_iter *ast_json_object_iter(struct ast_json *object)
+{
+	return json_object_iter((json_t *)object);
+}
+struct ast_json_iter *ast_json_object_iter_at(struct ast_json *object, const char *key)
+{
+	return json_object_iter_at((json_t *)object, key);
+}
+struct ast_json_iter *ast_json_object_iter_next(struct ast_json *object, struct ast_json_iter *iter)
+{
+	return json_object_iter_next((json_t *)object, iter);
+}
+const char *ast_json_object_iter_key(struct ast_json_iter *iter)
+{
+	return json_object_iter_key(iter);
+}
+struct ast_json *ast_json_object_iter_value(struct ast_json_iter *iter)
+{
+	return (struct ast_json *)json_object_iter_value(iter);
+}
+int ast_json_object_iter_set(struct ast_json *object, struct ast_json_iter *iter, struct ast_json *value)
+{
+	return json_object_iter_set_new((json_t *)object, iter, (json_t *)value);
+}
+
+/*!
+ * \brief Default flags for JSON encoding.
+ */
+static size_t dump_flags(void)
+{
+	/* There's a chance this could become a runtime flag */
+	int flags = JSON_COMPACT;
+#ifdef AST_DEVMODE
+	/* In dev mode, write readable JSON */
+	flags = JSON_INDENT(2) | JSON_PRESERVE_ORDER;
+#endif
+	return flags;
+}
+
+char *ast_json_dump_string(struct ast_json *root)
+{
+	return json_dumps((json_t *)root, dump_flags());
+}
+
+static int write_to_ast_str(const char *buffer, size_t size, void *data)
+{
+	struct ast_str **dst = data;
+	size_t str_size = ast_str_size(*dst);
+	size_t remaining = str_size - ast_str_strlen(*dst);
+	int ret;
+
+	/* While ast_str_append will grow the ast_str, it won't report
+	 * allocation errors. Fortunately, it's not that hard.
+	 */
+
+	/* Remaining needs to be big enough for buffer, plus null char */
+	while (remaining < size + 1) {
+		/* doubling the size of the buffer gives us 'amortized
+		 * constant' time.
+		 * See http://stackoverflow.com/a/249695/115478 for info.
+		 */
+		str_size *= 2;
+		remaining = str_size - ast_str_strlen(*dst);
+	}
+
+	ret = ast_str_make_space(dst, str_size);
+	if (ret == -1) {
+		/* Could not alloc; fail */
+		return -1;
+	}
+
+	ast_str_append_substr(dst, -1, buffer, size);
+	return 0;
+}
+
+int ast_json_dump_str(struct ast_json *root, struct ast_str **dst)
+{
+	return json_dump_callback((json_t *)root, write_to_ast_str, dst, dump_flags());
+}
+
+
+int ast_json_dump_file(struct ast_json *root, FILE *output)
+{
+	if (!root || !output) {
+		return -1;
+	}
+	return json_dumpf((json_t *)root, output, dump_flags());
+}
+int ast_json_dump_new_file(struct ast_json *root, const char *path)
+{
+	if (!root || !path) {
+		return -1;
+	}
+	return json_dump_file((json_t *)root, path, dump_flags());
+}
+
+/*!
+ * \brief Copy Jansson error struct to ours.
+ */
+static void copy_error(struct ast_json_error *error, const json_error_t *jansson_error)
+{
+	if (error && jansson_error) {
+		error->line = jansson_error->line;
+		error->column = jansson_error->column;
+		error->position = jansson_error->position;
+		ast_copy_string(error->text, jansson_error->text, sizeof(error->text));
+		ast_copy_string(error->source, jansson_error->source, sizeof(error->source));
+	}
+
+}
+
+static void parse_error(struct ast_json_error *error, const char *text, const char *source)
+{
+	if (error != NULL) {
+		error->line = 0;
+		error->column = 0;
+		error->position = 0;
+		strncpy(error->text, text, sizeof(error->text));
+		strncpy(error->source, source, sizeof(error->text));
+	}
+}
+
+struct ast_json *ast_json_load_string(const char *input, struct ast_json_error *error)
+{
+	json_error_t jansson_error = {};
+	struct ast_json *r = NULL;
+	if (input != NULL) {
+		r = (struct ast_json *)json_loads(input, 0, &jansson_error);
+		copy_error(error, &jansson_error);
+	} else {
+		parse_error(error, "NULL input string", "<null>");
+	}
+	return r;
+}
+
+struct ast_json *ast_json_load_str(const struct ast_str *input, struct ast_json_error *error)
+{
+	return ast_json_load_string(ast_str_buffer(input), error);
+}
+
+struct ast_json *ast_json_load_buf(const char *buffer, size_t buflen, struct ast_json_error *error)
+{
+	json_error_t jansson_error = {};
+	struct ast_json *r = (struct ast_json *)json_loadb(buffer, buflen, 0, &jansson_error);
+	copy_error(error, &jansson_error);
+	return r;
+}
+struct ast_json *ast_json_load_file(FILE *input, struct ast_json_error *error)
+{
+	json_error_t jansson_error = {};
+	struct ast_json *r = NULL;
+	if (input != NULL) {
+		r = (struct ast_json *)json_loadf(input, 0, &jansson_error);
+		copy_error(error, &jansson_error);
+	} else {
+		parse_error(error, "NULL input file", "<null>");
+	}
+	return r;
+}
+struct ast_json *ast_json_load_new_file(const char *path, struct ast_json_error *error)
+{
+	json_error_t jansson_error = {};
+	struct ast_json *r = (struct ast_json *)json_load_file(path, 0, &jansson_error);
+	copy_error(error, &jansson_error);
+	return r;
+}
+
+struct ast_json *ast_json_pack(char const *format, ...)
+{
+	struct ast_json *ret;
+	va_list args;
+	va_start(args, format);
+	ret = ast_json_vpack(format, args);
+	va_end(args);
+	return ret;
+}
+struct ast_json *ast_json_vpack(char const *format, va_list ap)
+{
+	struct ast_json *r = NULL;
+	if (format) {
+		r = (struct ast_json *)json_vpack_ex(NULL, 0, format, ap);
+	}
+	return r;
+}
+
+struct ast_json *ast_json_copy(const struct ast_json *value)
+{
+	return (struct ast_json *)json_copy((json_t *)value);
+}
+struct ast_json *ast_json_deep_copy(const struct ast_json *value)
+{
+	return (struct ast_json *)json_deep_copy((json_t *)value);
+}
+
+static int unload_module(void)
+{
+	/* Nothing to do */
+	return 0;
+}
+
+static int load_module(void)
+{
+	/* Setup to use Asterisk custom allocators */
+	ast_json_reset_alloc_funcs();
+	return AST_MODULE_LOAD_SUCCESS;
+}
+
+AST_MODULE_INFO(ASTERISK_GPL_KEY, AST_MODFLAG_GLOBAL_SYMBOLS, "JSON library",
+		.load = load_module,
+		.unload = unload_module);