261 lines
9.5 KiB
C
261 lines
9.5 KiB
C
#include "hmpl.h"
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Json *eval_object(Arena *arena, const Json * const context, const char * const query) {
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if (!context || !query) return NULL;
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const Json *res = context;
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char *dot, *key = arena_strdup(arena, query);
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while ((dot = strchr(key, '.')) != NULL) {
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*dot = '\0';
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raise_debug("res: %s, key: %s, query: %s", json_to_string(arena, res), key, query);
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res = json_get_object_item(res, key);
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if (!res)
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return NULL;
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key = dot + 1;
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}
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raise_debug("res: %s, key: %s, query: %s", json_to_string(arena, res), key, query);
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return json_get_object_item(res, key);
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}
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char *eval_string(Arena *arena, const Json * const context, const char * const query) {
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Json *res = eval_object(arena, context, query);
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if (!res)
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return NULL;
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return json_to_string_with_opts(arena, res, JSON_RAW);
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}
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/* Modified: text is passed by reference so we can update it and free old allocations */
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// {{[prefix]key}}
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void hmpl_render_interpolation_tags(Arena *arena, char **text_ptr, const Json * const context, const char * const prefix) {
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raise_debug("hmpl_render_interpolation_tags");
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char start_pattern[256];
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snprintf(start_pattern, sizeof(start_pattern), "{{%s", prefix);
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int start_pattern_length = strlen(start_pattern);
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int offset = 0;
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while (1) {
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char *current_text = *text_ptr;
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char *start = strstr(current_text + offset, start_pattern);
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if (!start)
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break;
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int start_index = start - current_text;
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int key_start = start_index + start_pattern_length;
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char *end = strstr(start, "}}");
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if (!end)
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raise_exception("Malformed template: missing closing braces for interpolation tag");
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int key_length = (end - current_text) - key_start;
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char *key = arena_alloc(arena, key_length + 1);
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substr_clone(current_text, key, key_start, key_length);
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char *replacement = eval_string(arena, context, key);
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if (!replacement) {
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offset = (end - current_text) + 2;
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continue;
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}
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char *new_text = arena_repstr(arena, current_text,
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start_index,
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end - start + 2,
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replacement);
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*text_ptr = new_text;
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offset = start_index;
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}
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}
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// CREATE OR REPLACE FUNCTION common.render_template_loop_blocks(result TEXT, context JSONB)
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// RETURNS TEXT LANGUAGE plpgsql AS $$
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// DECLARE
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// loop_start INT;
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// key_end INT;
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// loop_end INT;
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// loop_key TEXT;
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// block TEXT;
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// rendered_block TEXT;
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// arr JSONB;
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// item JSONB;
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// item_text TEXT;
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// BEGIN
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// LOOP
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// loop_start := strpos(result, '{{#');
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// EXIT WHEN loop_start = 0; -- Exit if no loop start found.
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//
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// -- Locate the end of the loop key marker.
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// key_end := strpos(result, '}}', loop_start);
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// IF key_end = 0 THEN
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// RAISE EXCEPTION 'Malformed template: missing closing braces for loop start';
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// END IF;
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//
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// -- Extract the key used for the loop.
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// loop_key := substr_cloneing(result from loop_start + 3 for key_end - loop_start - 3);
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//
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// RAISE DEBUG 'loop key %', loop_key;
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//
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// -- Find the matching loop end marker for this key.
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// loop_end := strpos(result, '{{/#' || loop_key || '}}', key_end);
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// IF loop_end = 0 THEN
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// RAISE EXCEPTION 'Malformed template: missing loop end for key %', loop_key;
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// END IF;
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//
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// -- Extract the inner block of the loop.
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// block := substr_cloneing(result from key_end + 2 for loop_end - key_end - 2);
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//
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// -- Retrieve the JSON array from the context for the loop key.
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// arr := eval_value(context, loop_key);
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// rendered_block := '';
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//
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// -- If an array is found, iterate over each element.
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// IF arr IS NOT NULL AND jsonb_typeof(arr) = 'array' THEN
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// FOR item IN SELECT * FROM jsonb_array_elements(arr) LOOP
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// item_text := block; -- Begin with the raw block.
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// IF jsonb_typeof(item) != 'object' THEN
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// -- Replace interpolation for primitive values.
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// item_text := replace(item_text, '{{.}}', item::text);
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// ELSE
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// -- For object values, iterate over each key/value.
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// item_text := render_template_interpolations(item_text, item, '.'::CHAR(1));
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// item_text := render_template_conditions(item_text, item, '.');
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// END IF;
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// rendered_block := rendered_block || item_text;
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// END LOOP;
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// END IF;
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//
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// -- Replace the entire loop block in the result with the rendered content.
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// result := substr_cloneing(result from 1 for loop_start - 1)
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// || rendered_block
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// || substr_cloneing(result from loop_end + char_length('{{/#' || loop_key || '}}'));
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// END LOOP;
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//
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// RETURN result;
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// END $$;
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// {{#array_key}}
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void hmpl_render_section_tags(Arena *arena, char **text_ptr, Json *context, const char * const prefix_start, const char * const prefix_end, const char * const separator_pattern){
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raise_debug("hmpl_render_section_tags(%p, %s, <optimized>, %s, %s, %s)", arena, *text_ptr, prefix_start, prefix_end, separator_pattern);
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char start_pattern[32];
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snprintf(start_pattern, sizeof(start_pattern), "{{%s", prefix_start);
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int start_pattern_length = strlen(start_pattern);
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// TODO: rename close_tag_start_pattern
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char end_pattern[32];
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snprintf(end_pattern, sizeof(end_pattern), "{{%s", prefix_end);
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int end_pattern_length = strlen(end_pattern);
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int separator_pattern_length = strlen(separator_pattern);
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if (!separator_pattern || separator_pattern_length == 0) {
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raise_exception("Unexpected usage: separator pattern cannot be empty");
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}
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int offset = 0;
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while (1) {
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char *current_text = *text_ptr;
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char *opening_tag_start = strstr(current_text + offset, start_pattern);
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if (!opening_tag_start)
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break;
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int start_index = opening_tag_start - current_text;
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int relative_key_start = start_index + start_pattern_length;
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char *opening_tag_separator = strstr(opening_tag_start, separator_pattern);
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if (!opening_tag_start) {
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raise_exception("Malformed template: missing separator for section tag or not specifiet name for element");
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exit(1);
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}
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int separator_index = opening_tag_separator - current_text;
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int element_name_start = separator_index + separator_pattern_length;
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char *opening_tag_end = strstr(opening_tag_separator, "}}");
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if (!opening_tag_end) {
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raise_exception("Malformed template: missing closing braces for section tag");
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exit(1);
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}
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assert((size_t)opening_tag_end > (size_t)opening_tag_separator);
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assert((size_t)opening_tag_separator > (size_t)opening_tag_start);
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int key_length = (opening_tag_separator - current_text) - relative_key_start;
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assert(key_length > 0);
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char *key = arena_alloc(arena, key_length + 1);
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substr_clone(current_text, key, relative_key_start, key_length);
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int element_name_length = (opening_tag_end - current_text) - element_name_start;
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assert(element_name_length > 0);
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char *element_name = arena_alloc(arena, element_name_length + 1);
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substr_clone(current_text, element_name, element_name_start, element_name_length);
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int close_tag_patern_length = start_pattern_length + key_length + end_pattern_length;
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char *close_tag_patern = arena_alloc(arena, close_tag_patern_length + 1);
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snprintf(close_tag_patern, sizeof(*close_tag_patern), "%s%s%s", start_pattern, key, end_pattern);
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char *close_tag = strstr(opening_tag_end + offset + 1, close_tag_patern);
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if (!close_tag) {
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raise_exception("Malformed template: missing loop end for key %s", key);
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exit(1);
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}
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Json *arr = eval_object(arena, context, key);
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if (arr && arr->type == JSON_ARRAY) {
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size_t elem_count = 0;
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for (Json *e = arr->child; e; e = e->next) elem_count++;
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char *replacement = arena_alloc(arena, MEM_KiB * elem_count);
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size_t offset = 0;
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char *block_buff = arena_alloc(arena, MEM_KiB);
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size_t relative_block_start = (size_t)opening_tag_end + 2 - (size_t)current_text;
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raise_trace("relative_block_start: %p = %p - 2 - %p", opening_tag_end, current_text);
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size_t block_len = (size_t)opening_tag_end - (size_t)close_tag - 2;
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raise_trace("block_len %p = %p - %p - 2", block_len, opening_tag_end, close_tag);
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assert(block_len > 0);
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substr_clone(current_text, block_buff, relative_block_start, block_len);
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for (Json *elem = arr->child; elem; elem = elem->next) {
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char *block = arena_strdup(arena, block_buff);
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char *prefix = arena_alloc(arena, element_name_length + 2);
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snprintf(prefix, element_name_length + 2, "%s.", element_name);
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hmpl_render_interpolation_tags(arena, &block, context, prefix);
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raise_trace("block after: %s", block);
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size_t block_len = strlen(block);
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memcpy(replacement + offset, block, block_len);
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offset += block_len;
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}
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replacement[offset] = '\0';
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raise_trace("replacement: %s", replacement);
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char *new_text = arena_repstr(arena, current_text,
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(size_t)opening_tag_start - 1,
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close_tag + close_tag_patern_length - opening_tag_start + 2,
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replacement);
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*text_ptr = new_text;
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}
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offset = start_index;
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}
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}
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void hmpl_render_with_arena(Arena *arena, char **text, const Json * const context) {
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if (context->type != JSON_OBJECT) {
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raise_exception("Malformed context: context is not json");
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exit(1);
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}
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hmpl_render_interpolation_tags(arena, text, context, "");
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}
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void hmpl_render(char **text, const Json * const context) {
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Arena arena = arena_init(MEM_MiB);
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hmpl_render_with_arena(&arena, text, context);
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arena_free(&arena);
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}
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