feat: hel: render without execute
This commit is contained in:
307
package/c/hel/hel.c
Executable file
307
package/c/hel/hel.c
Executable file
@@ -0,0 +1,307 @@
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#include "postgres.h"
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#include "fmgr.h"
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#include "utils/builtins.h"
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#include "utils/json.h"
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#include "hectic.h"
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#include <string.h>
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#ifdef PG_MODULE_MAGIC
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PG_MODULE_MAGIC;
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#endif
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/* Helper function to get a JSON value by key path */
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static Json *json_get_by_path(Arena *arena, const Json *context, const char *key_path) {
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if (!context || !key_path || !*key_path) {
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return NULL;
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}
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char *path_copy = arena_strdup(arena, key_path);
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char *token = strtok(path_copy, ".");
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Json *current = (Json*)context;
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while (token && current) {
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current = json_get_object_item(current, token);
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token = strtok(NULL, ".");
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}
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return current;
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}
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/* Convert JSON value to string */
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static char *json_value_to_string(Arena *arena, const Json *json) {
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if (!json) {
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return "";
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}
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switch (json->type) {
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case JSON_STRING:
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return json->value.string;
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case JSON_NUMBER: {
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char *buf = arena_alloc(arena, 64);
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snprintf(buf, 64, "%.6g", json->value.number);
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return buf;
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}
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case JSON_BOOL:
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return json->value.boolean ? "true" : "false";
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case JSON_NULL:
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return "";
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case JSON_ARRAY:
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case JSON_OBJECT:
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return json_to_string(arena, json);
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default:
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return "";
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}
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}
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/* Forward declaration for recursive function */
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static char *render_template_node(Arena *arena, const TemplateNode *node, const Json *context);
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/* Render a text node */
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static char *render_text_node(Arena *arena, const TemplateNode *node) {
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if (!node || node->type != TEMPLATE_NODE_TEXT) {
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return "";
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}
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return node->value.text.content;
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}
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/* Render an interpolation node */
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static char *render_interpolation_node(Arena *arena, const TemplateNode *node, const Json *context) {
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if (!node || node->type != TEMPLATE_NODE_INTERPOLATE || !context) {
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return "";
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}
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const char *key = node->value.interpolate.key;
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Json *value = json_get_by_path(arena, context, key);
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if (!value) {
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return "";
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}
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return json_value_to_string(arena, value);
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}
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/* Render a section node (for loop) */
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static char *render_section_node(Arena *arena, const TemplateNode *node, const Json *context) {
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if (!node || node->type != TEMPLATE_NODE_SECTION || !context) {
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return "";
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}
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const char *collection_key = node->value.section.collection;
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const char *iterator_name = node->value.section.iterator;
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TemplateNode *body = node->value.section.body;
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Json *collection = json_get_by_path(arena, context, collection_key);
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if (!collection || collection->type != JSON_ARRAY) {
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return "";
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}
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size_t buffer_size = 1024;
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char *buffer = arena_alloc(arena, buffer_size);
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size_t buffer_pos = 0;
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Json *item = collection->value.child;
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while (item) {
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const char *empty_json = "{}";
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Json *iter_context = json_parse(arena, &empty_json);
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if (!iter_context) {
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return "";
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}
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Json *item_json = arena_alloc(arena, sizeof(Json));
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memcpy(item_json, item, sizeof(Json));
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item_json->key = arena_strdup(arena, iterator_name);
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item_json->next = NULL;
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char *rendered_body = render_template_node(arena, body, iter_context);
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size_t rendered_len = strlen(rendered_body);
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if (buffer_pos + rendered_len + 1 > buffer_size) {
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buffer_size = (buffer_pos + rendered_len + 1) * 2;
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buffer = arena_realloc(arena, buffer, buffer_size / 2, buffer_size);
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}
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strcpy(buffer + buffer_pos, rendered_body);
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buffer_pos += rendered_len;
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item = item->next;
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}
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buffer[buffer_pos] = '\0';
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return buffer;
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}
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/* Render an include node */
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static char *render_include_node(Arena *arena, const TemplateNode *node, const Json *context) {
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if (!node || node->type != TEMPLATE_NODE_INCLUDE || !context) {
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return "";
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}
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const char *include_key = node->value.include.key;
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Json *include_value = json_get_by_path(arena, context, include_key);
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if (!include_value || include_value->type != JSON_ARRAY) {
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return "";
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}
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char *buffer = arena_alloc(arena, 1024);
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size_t buffer_pos = 0;
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Json *include_item = include_value->value.child;
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while (include_item) {
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if (include_item->type == JSON_OBJECT) {
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Json *template_json = json_get_object_item(include_item, "template");
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Json *content_json = json_get_object_item(include_item, "content");
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Json *context_json = json_get_object_item(include_item, "context");
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if (template_json && template_json->type == JSON_STRING) {
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const char *template_str = template_json->value.string;
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const Json *include_context = context_json ? context_json : context;
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TemplateConfig config = template_default_config();
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TemplateResult template_result = template_parse(arena, &template_str, &config);
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if (!IS_RESULT_ERROR(template_result)) {
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TemplateNode template_node = RESULT_SOME_VALUE(template_result);
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char *rendered = render_template_node(arena, &template_node, include_context);
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buffer_pos += sprintf(buffer + buffer_pos, "%s", rendered);
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}
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} else if (content_json && content_json->type == JSON_STRING) {
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buffer_pos += sprintf(buffer + buffer_pos, "%s", content_json->value.string);
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}
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}
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include_item = include_item->next;
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}
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buffer[buffer_pos] = '\0';
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return buffer;
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}
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/* Render a template node tree recursively */
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static char *render_template_node(Arena *arena, const TemplateNode *node, const Json *context) {
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if (!node) {
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return "";
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}
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size_t buffer_size = 4096;
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char *output = arena_alloc(arena, buffer_size);
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size_t output_pos = 0;
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const TemplateNode *current = node;
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while (current) {
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char *rendered = NULL;
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switch (current->type) {
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case TEMPLATE_NODE_TEXT:
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rendered = render_text_node(arena, current);
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break;
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case TEMPLATE_NODE_INTERPOLATE:
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rendered = render_interpolation_node(arena, current, context);
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break;
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case TEMPLATE_NODE_SECTION:
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rendered = render_section_node(arena, current, context);
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break;
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case TEMPLATE_NODE_INCLUDE:
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rendered = render_include_node(arena, current, context);
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break;
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case TEMPLATE_NODE_EXECUTE:
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todo;
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rendered = "";
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break;
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default:
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rendered = "";
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break;
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}
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size_t rendered_len = strlen(rendered);
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if (output_pos + rendered_len + 1 > buffer_size) {
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buffer_size = (output_pos + rendered_len + 1) * 2;
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output = arena_realloc(arena, output, buffer_size / 2, buffer_size);
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}
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strcpy(output + output_pos, rendered);
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output_pos += rendered_len;
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if (current->children) {
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char *children_rendered = render_template_node(arena, current->children, context);
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size_t children_len = strlen(children_rendered);
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if (output_pos + children_len + 1 > buffer_size) {
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buffer_size = (output_pos + children_len + 1) * 2;
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output = arena_realloc(arena, output, buffer_size / 2, buffer_size);
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}
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strcpy(output + output_pos, children_rendered);
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output_pos += children_len;
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}
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current = current->next;
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}
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output[output_pos] = '\0';
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return output;
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}
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/* Define the function render */
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PG_FUNCTION_INFO_V1(render);
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/*
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* Function to render templates using hectic library with JSON context
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* Arguments:
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* 1. declare - JSON context for rendering
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* 2. template - The template text to render
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*/
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Datum render(PG_FUNCTION_ARGS)
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{
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text *context_text = PG_GETARG_TEXT_PP(0);
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text *template_text = PG_GETARG_TEXT_PP(1);
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/* Convert input text to C string */
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char *template_str = text_to_cstring(template_text);
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char *context_str = text_to_cstring(context_text);
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/* Initialize arena for memory management */
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Arena arena = arena_init(MEM_MiB);
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/* Parse the JSON context */
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const char *json_ptr = context_str;
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Json *context = json_parse(&arena, &json_ptr);
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if (!context) {
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arena_free(&arena);
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ereport(ERROR, (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
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errmsg("Invalid JSON context")));
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}
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/* Parse the template text */
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const char *template_ptr = template_str;
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TemplateConfig config = template_default_config();
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TemplateResult template_result = template_parse(&arena, &template_ptr, &config);
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if (IS_RESULT_ERROR(template_result)) {
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arena_free(&arena);
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ereport(ERROR, (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
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errmsg("Failed to parse template: %s",
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RESULT_ERROR_MESSAGE(template_result))));
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}
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/* Render the template */
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TemplateNode root_node = RESULT_SOME_VALUE(template_result);
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char *result_str = render_template_node(&arena, &root_node, context);
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/* Prepare return value */
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text *result = cstring_to_text(result_str);
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arena_free(&arena);
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PG_RETURN_TEXT_P(result);
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}
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