refactor(hmpl): rewrite via arenas

package/c/hmpl/hmpl.c

@@ -5,29 +5,29 @@
 #include "chectic.h"
 #include "cjson/cJSON.h"
 
+static Arena arena;
+
 char *eval(cJSON *context, const char *key) {
     if (!context || !key) return NULL;
-    char *key_copy = strdup(key);
+    char *key_copy = arena_strdup(&arena, key);
     char *token, *rest = key_copy;
     cJSON *res = context;
-
     while ((token = strtok_r(rest, ".", &rest))) {
         res = cJSON_GetObjectItemCaseSensitive(res, token);
-        if (!res) {
-            free(key_copy);
+        if (!res)
             return NULL;
-        }
     }
-    free(key_copy);
-
     if (cJSON_IsString(res) && res->valuestring)
-        return strdup(res->valuestring);
+        return arena_strdup(&arena, res->valuestring);
     else if (cJSON_IsNumber(res)) {
         char buf[64];
         snprintf(buf, sizeof(buf), "%g", res->valuedouble);
-        return strdup(buf);
+        return arena_strdup(&arena, buf);
     }
-    return cJSON_PrintUnformatted(res);
+    char *temp = cJSON_PrintUnformatted(res);
+    char *result = arena_strdup(&arena, temp);
+    free(temp);
+    return result;
 }
 
 void substring(const char *src, char *dest, size_t start, size_t len) {
@@ -48,14 +48,10 @@ char* replace_substring(const char* src, int start, int end, const char* replace
     int src_len = strlen(src);
     int rep_len = strlen(replacement);
     int new_len = src_len - (end - start + 1) + rep_len;
-
-    char* new_str = malloc(new_len + 1);
-    if (!new_str) return NULL;
-
-    memcpy(new_str, src, start);                     // copy before
+    char* new_str = arena_alloc(&arena, new_len + 1);
+    memcpy(new_str, src, start);                       // copy before
     memcpy(new_str + start, replacement, rep_len);     // insert replacement
-    strcpy(new_str + start + rep_len, src + end + 1);    // copy after
-
+    strcpy(new_str + start + rep_len, src + end + 1);  // copy after
     return new_str;
 }
 
@@ -77,32 +73,27 @@ void render_template_placeholders(char **text_ptr, cJSON *context, const char *p
         raise_debug("start: %d", key_start);
 
         char *placeholder_end = strstr(placeholder_start, "}}");
-        if (!placeholder_end) {
+        if (!placeholder_end)
             raise_exception("Malformed template: missing closing braces for placeholder start");
-        }
         int key_length = (placeholder_end - current_text) - key_start;
-        char *placeholder_key = malloc(key_length + 1);
-        if (!placeholder_key)
-            raise_exception("Memory allocation error");
+        char *placeholder_key = arena_alloc(&arena, key_length + 1);
         substring(current_text, placeholder_key, key_start, key_length);
         raise_debug("key: %s", placeholder_key);
 
         char *replacement = eval(context, placeholder_key);
         raise_debug("%s = eval(context, %s)", replacement ? replacement : "NULL", placeholder_key);
-        free(placeholder_key);
         if (!replacement) {
-            offset = (placeholder_end - current_text) + 2; // skip past the placeholder
+            offset = (placeholder_end - current_text) + 2;
             continue;
         }
-        int placeholder_end_index = (placeholder_end - current_text) + 2; // include "}}"
+        int placeholder_end_index = (placeholder_end - current_text) + 2;
+        char *new_text = replace_substring(current_text,
+	  start_index,
+	  placeholder_end_index - 1,
+	  replacement);
 
-        char *new_text =
-	  replace_substring(current_text, start_index, placeholder_end_index - 1, replacement);
-        free(replacement);
-        free(current_text);    // free the old text
-			       
         *text_ptr = new_text;
-        offset = start_index;  // resume search from the replaced location
+        offset = start_index;
     }
 }
 
@@ -111,35 +102,41 @@ void render_template(char **text, cJSON *context) {
 }
 
 int main(int argc, char *argv[]) {
-    init_logger();
-    raise_info("start");
+  init_logger();
+  raise_info("start");
 
-    char *text = NULL;
-    const char *json_input = (argc > 1 ? argv[1] : "{}");
-    cJSON *context = cJSON_Parse(json_input);
-    if (!context) {
-        fprintf(stderr, "Error parsing JSON\n");
-        return 1;
+  arena = arena_init(1024 * 1024);
+
+  raise_info("read the arguments");
+  char *text = NULL;
+  const char *json_input = (argc > 1 ? argv[1] : "{}");
+  cJSON *context = cJSON_Parse(json_input);
+  if (!context) {
+      fprintf(stderr, "Error parsing JSON\n");
+      return 1;
+  }
+
+  if (argc > 2) {
+    text = arena_strdup(&arena, argv[2]);
+  } else if (!isatty(fileno(stdin))) {
+    size_t size = 0;
+    char *heap_text = NULL;
+    ssize_t len = getdelim(&heap_text, &size, '\0', stdin);
+    if (len < 0) {
+      perror("read stdin");
+      cJSON_Delete(context);
+      return 1;
     }
+    text = arena_strdup(&arena, heap_text);
+    free(heap_text);  // free temporary heap allocation
+  } else {
+    text = arena_strdup(&arena, "");
+  }
 
-    if (argc > 2) {
-        text = strdup(argv[2]);
-    } else if (!isatty(fileno(stdin))) {
-        size_t size = 0;
-        ssize_t len = getdelim(&text, &size, '\0', stdin);
-        if (len < 0) {
-            perror("read stdin");
-            cJSON_Delete(context);
-            return 1;
-        }
-    } else {
-        text = strdup("");
-    }
+  render_template(&text, context);
+  printf("%s", text);
 
-    render_template(&text, context);
-    printf("%s", text);
-
-    free(text);
-    cJSON_Delete(context);
-    return 0;
+  arena_free(&arena);
+  cJSON_Delete(context);
+  return 0;
 }