/* json-generator.c - JSON tree builder

 *

 * This file is part of JSON-GLib

 *

 * SPDX-FileCopyrightText: 2010  Luca Bruno <lethalman88@gmail.com>

 * SPDX-FileCopyrightText: 2015  Collabora Ltd.

 * SPDX-License-Identifier: LGPL-2.1-or-later

 *

 * 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:

 *   Luca Bruno  <lethalman88@gmail.com>

 *   Philip Withnall  <philip.withnall@collabora.co.uk>

 */

/**

 * JsonBuilder:

 *

 * `JsonBuilder` provides an object for generating a JSON tree.

 *

 * The root of the JSON tree can be either a [struct@Json.Object] or a [struct@Json.Array].

 * Thus the first call must necessarily be either

 * [method@Json.Builder.begin_object] or [method@Json.Builder.begin_array].

 *

 * For convenience to language bindings, most `JsonBuilder` method return the

 * instance, making it easy to chain function calls.

 *

 * ## Using `JsonBuilder`

 *

 * ```c

 * g_autoptr(JsonBuilder) builder = json_builder_new ();

 *

 * json_builder_begin_object (builder);

 *

 * json_builder_set_member_name (builder, "url");

 * json_builder_add_string_value (builder, "http://www.gnome.org/img/flash/two-thirty.png");

 *

 * json_builder_set_member_name (builder, "size");

 * json_builder_begin_array (builder);

 * json_builder_add_int_value (builder, 652);

 * json_builder_add_int_value (builder, 242);

 * json_builder_end_array (builder);

 *

 * json_builder_end_object (builder);

 *

 * g_autoptr(JsonNode) root = json_builder_get_root (builder);

 *

 * g_autoptr(JsonGenerator) gen = json_generator_new ();

 * json_generator_set_root (gen, root);

 * g_autofree char *str = json_generator_to_data (gen, NULL);

 *

 * // str now contains the following JSON data

 * // { "url" : "http://www.gnome.org/img/flash/two-thirty.png", "size" : [ 652, 242 ] }

 * ```

 */

#include "config.h"

#include <stdlib.h>

#include <string.h>

#include "json-types-private.h"

#include "json-builder.h"

struct _JsonBuilderPrivate

{

  GQueue *stack;

  JsonNode *root;

  gboolean immutable;

};

enum

{

  PROP_IMMUTABLE = 1,

  PROP_LAST

};

static GParamSpec *builder_props[PROP_LAST] = { NULL, };

typedef enum

{

  JSON_BUILDER_MODE_OBJECT,

  JSON_BUILDER_MODE_ARRAY,

  JSON_BUILDER_MODE_MEMBER

} JsonBuilderMode;

typedef struct

{

  JsonBuilderMode mode;

  union

  {

    JsonObject *object;

    JsonArray *array;

  } data;

  gchar *member_name;

} JsonBuilderState;

static void

json_builder_state_free (JsonBuilderState *state)

{

  if (G_LIKELY (state))

    {

      switch (state->mode)

        {

        case JSON_BUILDER_MODE_OBJECT:

        case JSON_BUILDER_MODE_MEMBER:

          json_object_unref (state->data.object);

          g_free (state->member_name);

          state->data.object = NULL;

          state->member_name = NULL;

          break;

        case JSON_BUILDER_MODE_ARRAY:

          json_array_unref (state->data.array);

          state->data.array = NULL;

          break;

        default:

          g_assert_not_reached ();

        }

      g_free (state);

    }

}

G_DEFINE_TYPE_WITH_PRIVATE (JsonBuilder, json_builder, G_TYPE_OBJECT)

static void

json_builder_free_all_state (JsonBuilder *builder)

{

  JsonBuilderState *state;

  while (!g_queue_is_empty (builder->priv->stack))

    {

      state = g_queue_pop_head (builder->priv->stack);

      json_builder_state_free (state);

    }

  if (builder->priv->root)

    {

      json_node_unref (builder->priv->root);

      builder->priv->root = NULL;

    }

}

static void

json_builder_finalize (GObject *gobject)

{

  JsonBuilderPrivate *priv = json_builder_get_instance_private ((JsonBuilder *) gobject);

  json_builder_free_all_state (JSON_BUILDER (gobject));

  g_queue_free (priv->stack);

  priv->stack = NULL;

  G_OBJECT_CLASS (json_builder_parent_class)->finalize (gobject);

}

static void

json_builder_set_property (GObject      *gobject,

                           guint         prop_id,

                           const GValue *value,

                           GParamSpec   *pspec)

{

  JsonBuilderPrivate *priv = JSON_BUILDER (gobject)->priv;

  switch (prop_id)

    {

    case PROP_IMMUTABLE:

      /* Construct-only. */

      priv->immutable = g_value_get_boolean (value);

      break;

    default:

      G_OBJECT_WARN_INVALID_PROPERTY_ID (gobject, prop_id, pspec);

      break;

    }

}

static void

json_builder_get_property (GObject    *gobject,

                           guint       prop_id,

                           GValue     *value,

                           GParamSpec *pspec)

{

  JsonBuilderPrivate *priv = JSON_BUILDER (gobject)->priv;

  switch (prop_id)

    {

    case PROP_IMMUTABLE:

      g_value_set_boolean (value, priv->immutable);

      break;

    default:

      G_OBJECT_WARN_INVALID_PROPERTY_ID (gobject, prop_id, pspec);

      break;

    }

}

static void

json_builder_class_init (JsonBuilderClass *klass)

{

  GObjectClass *gobject_class = G_OBJECT_CLASS (klass);

  /**

   * JsonBuilder:immutable:

   *

   * Whether the tree should be immutable when created.

   *

   * Making the output immutable on creation avoids the expense

   * of traversing it to make it immutable later.

   *

   * Since: 1.2

   */

  builder_props[PROP_IMMUTABLE] =

    g_param_spec_boolean ("immutable",

                          "Immutable Output",

                          "Whether the builder output is immutable.",

                          FALSE,

                          G_PARAM_CONSTRUCT_ONLY | G_PARAM_READWRITE);

  gobject_class->set_property = json_builder_set_property;

  gobject_class->get_property = json_builder_get_property;

  gobject_class->finalize = json_builder_finalize;

  g_object_class_install_properties (gobject_class, PROP_LAST, builder_props);

}

static void

json_builder_init (JsonBuilder *builder)

{

  JsonBuilderPrivate *priv = json_builder_get_instance_private (builder);

  builder->priv = priv;

  priv->stack = g_queue_new ();

  priv->root = NULL;

}

static inline JsonBuilderMode

json_builder_current_mode (JsonBuilder *builder)

{

  JsonBuilderState *state = g_queue_peek_head (builder->priv->stack);

  return state->mode;

}

static inline gboolean

json_builder_is_valid_add_mode (JsonBuilder *builder)

{

  JsonBuilderMode mode = json_builder_current_mode (builder);

  return mode == JSON_BUILDER_MODE_MEMBER || mode == JSON_BUILDER_MODE_ARRAY;

}

/**

 * json_builder_new:

 *

 * Creates a new `JsonBuilder`.

 *

 * You can use this object to generate a JSON tree and obtain the root node.

 *

 * Return value: the newly created builder instance

 */

JsonBuilder *

json_builder_new (void)

{

  return g_object_new (JSON_TYPE_BUILDER, NULL);

}

/**

 * json_builder_new_immutable: (constructor)

 *

 * Creates a new, immutable `JsonBuilder` instance.

 *

 * It is equivalent to setting the [property@Json.Builder:immutable] property

 * set to `TRUE` at construction time.

 *

 * Since: 1.2

 * Returns: (transfer full): the newly create builder instance

 */

JsonBuilder *

json_builder_new_immutable (void)

{

  return g_object_new (JSON_TYPE_BUILDER, "immutable", TRUE, NULL);

}

/**

 * json_builder_get_root:

 * @builder: a builder

 *

 * Returns the root of the currently constructed tree.

 *

 * if the build is incomplete (ie: if there are any opened objects, or any

 * open object members and array elements) then this function will return

 * `NULL`.

 *

 * Return value: (nullable) (transfer full): the root node

 */

JsonNode *

json_builder_get_root (JsonBuilder *builder)

{

  JsonNode *root = NULL;

  g_return_val_if_fail (JSON_IS_BUILDER (builder), NULL);

  if (builder->priv->root)

    root = json_node_copy (builder->priv->root);

  /* Sanity check. */

  g_assert (!builder->priv->immutable ||

            root == NULL ||

            json_node_is_immutable (root));

  return root;

}

/**

 * json_builder_reset:

 * @builder: a builder

 *

 * Resets the state of the builder back to its initial state.

 */

void

json_builder_reset (JsonBuilder *builder)

{

  g_return_if_fail (JSON_IS_BUILDER (builder));

  json_builder_free_all_state (builder);

}

/**

 * json_builder_begin_object:

 * @builder: a builder

 *

 * Opens an object inside the given builder.

 *

 * You can add a new member to the object by using [method@Json.Builder.set_member_name],

 * followed by [method@Json.Builder.add_value].

 *

 * Once you added all members to the object, you must call [method@Json.Builder.end_object]

 * to close the object.

 *

 * If the builder is in an inconsistent state, this function will return `NULL`.

 *

 * Return value: (nullable) (transfer none): the builder instance

 */

JsonBuilder *

json_builder_begin_object (JsonBuilder *builder)

{

  JsonObject *object;

  JsonBuilderState *state;

  JsonBuilderState *cur_state;

  g_return_val_if_fail (JSON_IS_BUILDER (builder), NULL);

  g_return_val_if_fail (builder->priv->root == NULL, NULL);

  g_return_val_if_fail (g_queue_is_empty (builder->priv->stack) || json_builder_is_valid_add_mode (builder), NULL);

  object = json_object_new ();

  cur_state = g_queue_peek_head (builder->priv->stack);

  if (cur_state)

    {

      switch (cur_state->mode)

        {

        case JSON_BUILDER_MODE_ARRAY:

          json_array_add_object_element (cur_state->data.array, json_object_ref (object));

          break;

        case JSON_BUILDER_MODE_MEMBER:

          json_object_set_object_member (cur_state->data.object, cur_state->member_name, json_object_ref (object));

          g_free (cur_state->member_name);

          cur_state->member_name = NULL;

          cur_state->mode = JSON_BUILDER_MODE_OBJECT;

          break;

        default:

          g_assert_not_reached ();

        }

    }

  state = g_new (JsonBuilderState, 1);

  state->data.object = object;

  state->member_name = NULL;

  state->mode = JSON_BUILDER_MODE_OBJECT;

  g_queue_push_head (builder->priv->stack, state);

  return builder;

}

/**

 * json_builder_end_object:

 * @builder: a builder

 *

 * Closes the object inside the given builder that was opened by the most

 * recent call to [method@Json.Builder.begin_object].

 *

 * This function cannot be called after [method@Json.Builder.set_member_name].

 *

 * Return value: (nullable) (transfer none): the builder instance

 */

JsonBuilder *

json_builder_end_object (JsonBuilder *builder)

{

  JsonBuilderState *state;

  g_return_val_if_fail (JSON_IS_BUILDER (builder), NULL);

  g_return_val_if_fail (!g_queue_is_empty (builder->priv->stack), NULL);

  g_return_val_if_fail (json_builder_current_mode (builder) == JSON_BUILDER_MODE_OBJECT, NULL);

  state = g_queue_pop_head (builder->priv->stack);

  if (builder->priv->immutable)

    json_object_seal (state->data.object);

  if (g_queue_is_empty (builder->priv->stack))

    {

      builder->priv->root = json_node_new (JSON_NODE_OBJECT);

      json_node_take_object (builder->priv->root, json_object_ref (state->data.object));

      if (builder->priv->immutable)

        json_node_seal (builder->priv->root);

    }

  json_builder_state_free (state);

  return builder;

}

/**

 * json_builder_begin_array:

 * @builder: a builder

 *

 * Opens an array inside the given builder.

 *

 * You can add a new element to the array by using [method@Json.Builder.add_value].

 *

 * Once you added all elements to the array, you must call

 * [method@Json.Builder.end_array] to close the array.

 *

 * Return value: (nullable) (transfer none): the builder instance

 */

JsonBuilder *

json_builder_begin_array (JsonBuilder *builder)

{

  JsonArray *array;

  JsonBuilderState *state;

  JsonBuilderState *cur_state;

  g_return_val_if_fail (JSON_IS_BUILDER (builder), NULL);

  g_return_val_if_fail (builder->priv->root == NULL, NULL);

  g_return_val_if_fail (g_queue_is_empty (builder->priv->stack) || json_builder_is_valid_add_mode (builder), NULL);

  array = json_array_new ();

  cur_state = g_queue_peek_head (builder->priv->stack);

  if (cur_state)

    {

      switch (cur_state->mode)

        {

        case JSON_BUILDER_MODE_ARRAY:

          json_array_add_array_element (cur_state->data.array, json_array_ref (array));

          break;

        case JSON_BUILDER_MODE_MEMBER:

          json_object_set_array_member (cur_state->data.object, cur_state->member_name, json_array_ref (array));

          g_free (cur_state->member_name);

          cur_state->member_name = NULL;

          cur_state->mode = JSON_BUILDER_MODE_OBJECT;

          break;

        default:

          g_assert_not_reached ();

        }

    }

  state = g_new (JsonBuilderState, 1);

  state->data.array = array;

  state->mode = JSON_BUILDER_MODE_ARRAY;

  g_queue_push_head (builder->priv->stack, state);

  return builder;

}

/**

 * json_builder_end_array:

 * @builder: a builder

 *

 * Closes the array inside the given builder that was opened by the most

 * recent call to [method@Json.Builder.begin_array].

 *

 * This function cannot be called after [method@Json.Builder.set_member_name].

 *

 * Return value: (nullable) (transfer none): the builder instance

 */

JsonBuilder *

json_builder_end_array (JsonBuilder *builder)

{

  JsonBuilderState *state;

  g_return_val_if_fail (JSON_IS_BUILDER (builder), NULL);

  g_return_val_if_fail (!g_queue_is_empty (builder->priv->stack), NULL);

  g_return_val_if_fail (json_builder_current_mode (builder) == JSON_BUILDER_MODE_ARRAY, NULL);

  state = g_queue_pop_head (builder->priv->stack);

  if (builder->priv->immutable)

    json_array_seal (state->data.array);

  if (g_queue_is_empty (builder->priv->stack))

    {

      builder->priv->root = json_node_new (JSON_NODE_ARRAY);

      json_node_take_array (builder->priv->root, json_array_ref (state->data.array));

      if (builder->priv->immutable)

        json_node_seal (builder->priv->root);

    }

  json_builder_state_free (state);

  return builder;

}

/**

 * json_builder_set_member_name:

 * @builder: a builder

 * @member_name: the name of the member

 *

 * Sets the name of the member in an object.

 *

 * This function must be followed by of these functions:

 *

 *  - [method@Json.Builder.add_value], to add a scalar value to the member

 *  - [method@Json.Builder.begin_object], to add an object to the member

 *  - [method@Json.Builder.begin_array], to add an array to the member

 *

 * This function can only be called within an open object.

 *

 * Return value: (nullable) (transfer none): the builder instance

 */

JsonBuilder *

json_builder_set_member_name (JsonBuilder *builder,

                              const gchar *member_name)

{

  JsonBuilderState *state;

  g_return_val_if_fail (JSON_IS_BUILDER (builder), NULL);

  g_return_val_if_fail (member_name != NULL, NULL);

  g_return_val_if_fail (!g_queue_is_empty (builder->priv->stack), NULL);

  g_return_val_if_fail (json_builder_current_mode (builder) == JSON_BUILDER_MODE_OBJECT, NULL);

  state = g_queue_peek_head (builder->priv->stack);

  state->member_name = g_strdup (member_name);

  state->mode = JSON_BUILDER_MODE_MEMBER;

  return builder;

}

/**

 * json_builder_add_value:

 * @builder: a builder

 * @node: (transfer full): the value of the member or element

 *

 * Adds a value to the currently open object member or array.

 *

 * If called after [method@Json.Builder.set_member_name], sets the given node

 * as the value of the current member in the open object; otherwise, the node

 * is appended to the elements of the open array.

 *

 * The builder will take ownership of the node.

 *

 * Return value: (nullable) (transfer none): the builder instance

 */

JsonBuilder *

json_builder_add_value (JsonBuilder *builder,

                        JsonNode    *node)

{

  JsonBuilderState *state;

  g_return_val_if_fail (JSON_IS_BUILDER (builder), NULL);

  g_return_val_if_fail (node != NULL, NULL);

  g_return_val_if_fail (!g_queue_is_empty (builder->priv->stack), NULL);

  g_return_val_if_fail (json_builder_is_valid_add_mode (builder), NULL);

  state = g_queue_peek_head (builder->priv->stack);

  if (builder->priv->immutable)

    json_node_seal (node);

  switch (state->mode)

    {

    case JSON_BUILDER_MODE_MEMBER:

      json_object_set_member (state->data.object, state->member_name, node);

      g_free (state->member_name);

      state->member_name = NULL;

      state->mode = JSON_BUILDER_MODE_OBJECT;

      break;

    case JSON_BUILDER_MODE_ARRAY:

      json_array_add_element (state->data.array, node);

      break;

    default:

      g_assert_not_reached ();

    }

  return builder;

}

/**

 * json_builder_add_int_value:

 * @builder: a builder

 * @value: the value of the member or element

 *

 * Adds an integer value to the currently open object member or array.

 *

 * If called after [method@Json.Builder.set_member_name], sets the given value

 * as the value of the current member in the open object; otherwise, the value

 * is appended to the elements of the open array.

 *

 * See also: [method@Json.Builder.add_value]

 *

 * Return value: (nullable) (transfer none): the builder instance

 */

JsonBuilder *

json_builder_add_int_value (JsonBuilder *builder,

                            gint64       value)

{

  JsonBuilderState *state;

  g_return_val_if_fail (JSON_IS_BUILDER (builder), NULL);

  g_return_val_if_fail (!g_queue_is_empty (builder->priv->stack), NULL);

  g_return_val_if_fail (json_builder_is_valid_add_mode (builder), NULL);

  state = g_queue_peek_head (builder->priv->stack);

  switch (state->mode)

    {

    case JSON_BUILDER_MODE_MEMBER:

      json_object_set_int_member (state->data.object, state->member_name, value);

      g_free (state->member_name);

      state->member_name = NULL;

      state->mode = JSON_BUILDER_MODE_OBJECT;

      break;

    case JSON_BUILDER_MODE_ARRAY:

      json_array_add_int_element (state->data.array, value);

      break;

    default:

      g_assert_not_reached ();

    }

  return builder;

}

/**

 * json_builder_add_double_value:

 * @builder: a builder

 * @value: the value of the member or element

 *

 * Adds a floating point value to the currently open object member or array.

 *

 * If called after [method@Json.Builder.set_member_name], sets the given value

 * as the value of the current member in the open object; otherwise, the value

 * is appended to the elements of the open array.

 *

 * See also: [method@Json.Builder.add_value]

 *

 * Return value: (nullable) (transfer none): the builder instance

 */

JsonBuilder *

json_builder_add_double_value (JsonBuilder *builder,

                               gdouble      value)

{

  JsonBuilderState *state;

  g_return_val_if_fail (JSON_IS_BUILDER (builder), NULL);

  g_return_val_if_fail (!g_queue_is_empty (builder->priv->stack), NULL);

  g_return_val_if_fail (json_builder_is_valid_add_mode (builder), NULL);

  state = g_queue_peek_head (builder->priv->stack);

  switch (state->mode)

    {

    case JSON_BUILDER_MODE_MEMBER:

      json_object_set_double_member (state->data.object, state->member_name, value);

      g_free (state->member_name);

      state->member_name = NULL;

      state->mode = JSON_BUILDER_MODE_OBJECT;

      break;

    case JSON_BUILDER_MODE_ARRAY:

      json_array_add_double_element (state->data.array, value);

      break;

    default:

      g_assert_not_reached ();

    }

  return builder;

}

/**

 * json_builder_add_boolean_value:

 * @builder: a builder

 * @value: the value of the member or element

 *

 * Adds a boolean value to the currently open object member or array.

 *

 * If called after [method@Json.Builder.set_member_name], sets the given value

 * as the value of the current member in the open object; otherwise, the value

 * is appended to the elements of the open array.

 *

 * See also: [method@Json.Builder.add_value]

 *

 * Return value: (nullable) (transfer none): the builder instance

 */

JsonBuilder *

json_builder_add_boolean_value (JsonBuilder *builder,

                                gboolean     value)

{

  JsonBuilderState *state;

  g_return_val_if_fail (JSON_IS_BUILDER (builder), NULL);

  g_return_val_if_fail (!g_queue_is_empty (builder->priv->stack), NULL);

  g_return_val_if_fail (json_builder_is_valid_add_mode (builder), NULL);

  state = g_queue_peek_head (builder->priv->stack);

  switch (state->mode)

    {

    case JSON_BUILDER_MODE_MEMBER:

      json_object_set_boolean_member (state->data.object, state->member_name, value);

      g_free (state->member_name);

      state->member_name = NULL;

      state->mode = JSON_BUILDER_MODE_OBJECT;

      break;

    case JSON_BUILDER_MODE_ARRAY:

      json_array_add_boolean_element (state->data.array, value);

      break;

    default:

      g_assert_not_reached ();

    }

  return builder;

}

/**

 * json_builder_add_string_value:

 * @builder: a builder

 * @value: the value of the member or element

 *

 * Adds a string value to the currently open object member or array.

 *

 * If called after [method@Json.Builder.set_member_name], sets the given value

 * as the value of the current member in the open object; otherwise, the value

 * is appended to the elements of the open array.

 *

 * See also: [method@Json.Builder.add_value]

 *

 * Return value: (nullable) (transfer none): the builder instance

 */

JsonBuilder *

json_builder_add_string_value (JsonBuilder *builder,

                               const gchar *value)

{

  JsonBuilderState *state;

  g_return_val_if_fail (JSON_IS_BUILDER (builder), NULL);

  g_return_val_if_fail (!g_queue_is_empty (builder->priv->stack), NULL);

  g_return_val_if_fail (json_builder_is_valid_add_mode (builder), NULL);

  state = g_queue_peek_head (builder->priv->stack);

  switch (state->mode)

    {

    case JSON_BUILDER_MODE_MEMBER:

      json_object_set_string_member (state->data.object, state->member_name, value);

      g_free (state->member_name);

      state->member_name = NULL;

      state->mode = JSON_BUILDER_MODE_OBJECT;

      break;

    case JSON_BUILDER_MODE_ARRAY:

      json_array_add_string_element (state->data.array, value);

      break;

    default:

      g_assert_not_reached ();

    }

  return builder;

}

/**

 * json_builder_add_null_value:

 * @builder: a builder

 *

 * Adds a null value to the currently open object member or array.

 *

 * If called after [method@Json.Builder.set_member_name], sets the given value

 * as the value of the current member in the open object; otherwise, the value

 * is appended to the elements of the open array.

 *

 * See also: [method@Json.Builder.add_value]

 *

 * Return value: (nullable) (transfer none): the builder instance

 */

JsonBuilder *

json_builder_add_null_value (JsonBuilder *builder)

{

  JsonBuilderState *state;

  g_return_val_if_fail (JSON_IS_BUILDER (builder), NULL);

  g_return_val_if_fail (!g_queue_is_empty (builder->priv->stack), NULL);

  g_return_val_if_fail (json_builder_is_valid_add_mode (builder), NULL);

  state = g_queue_peek_head (builder->priv->stack);

  switch (state->mode)

    {

    case JSON_BUILDER_MODE_MEMBER:

      json_object_set_null_member (state->data.object, state->member_name);

      g_free (state->member_name);

      state->member_name = NULL;

      state->mode = JSON_BUILDER_MODE_OBJECT;

      break;

    case JSON_BUILDER_MODE_ARRAY:

      json_array_add_null_element (state->data.array);

      break;

    default:

      g_assert_not_reached ();

    }

  return builder;

}