added database

src/db_get_all_users.c

@@ -0,0 +1,99 @@
+#include "database.h"
+#include "sql.h"
+#include "user.h"
+#include <string.h>
+
+char *db_get_all_users() {
+  pthread_mutex_lock(&db_mutex);
+  if (!db) {
+    fprintf(stderr, "Database not initialized\n");
+    pthread_mutex_unlock(&db_mutex);
+    return nullptr;
+  }
+  sqlite3_stmt *stmt;
+  int rc;
+
+  rc = sqlite3_prepare_v2(db, SELECT_ALL_USERS_SQL, -1, &stmt, nullptr);
+  if (rc != SQLITE_OK) {
+    fprintf(stderr, "Cannot prepare statement: %s\n", sqlite3_errmsg(db));
+    pthread_mutex_unlock(&db_mutex);
+    return nullptr;
+  }
+
+  char *result = malloc(1024);
+  if (!result) {
+    sqlite3_finalize(stmt);
+    pthread_mutex_unlock(&db_mutex);
+    return nullptr;
+  }
+
+  strcpy(result, "[");
+  size_t result_size = strlen(result);
+  size_t result_capacity = 1024;
+
+  int first_record = 1;
+
+  while ((rc = sqlite3_step(stmt)) == SQLITE_ROW) {
+    int id = sqlite3_column_int(stmt, 0);
+    const unsigned char *username = sqlite3_column_text(stmt, 1);
+    const unsigned char *email = sqlite3_column_text(stmt, 2);
+    const unsigned char *group = sqlite3_column_text(stmt, 4);
+    int is_superuser = sqlite3_column_int(stmt, 5);
+
+    char *escaped_username = json_escape((const char *) username);
+    char *escaped_email = json_escape((const char *) email);
+    char *escaped_group = json_escape((const char *) group);
+    if (!escaped_username || !escaped_email || !escaped_group) {
+      free(escaped_username);
+      free(escaped_email);
+      free(escaped_group);
+      sqlite3_finalize(stmt);
+      return NULL;
+    }
+
+    char record[512];
+    if (sqlite3_column_type(stmt, 2) == SQLITE_NULL) {
+      snprintf(record, sizeof(record),
+               "%s{\"id\":%d,\"username\":\"%s\",\"email\":\"%s\",\"group\":"
+               "\"%s\",\"is_superuser\":%s}",
+               first_record ? "" : ",", id, escaped_username, escaped_email,
+               escaped_group, is_superuser ? "true" : "false");
+    } else {
+      snprintf(record, sizeof(record),
+               "%s{\"id\":%d,\"username\":\"%s\",\"email\":\"%s\",\"group\":"
+               "\"%s\",\"is_superuser\":%s}",
+               first_record ? "" : ",", id, escaped_username, escaped_email,
+               escaped_group, is_superuser ? "true" : "false");
+    }
+
+    free(escaped_username);
+    free(escaped_email);
+    free(escaped_group);
+
+    size_t record_len = strlen(record);
+    if (result_size + record_len + 10 > result_capacity) {
+      result_capacity *= 2;
+      char *new_result = realloc(result, result_capacity);
+      if (!new_result) {
+        free(result);
+        sqlite3_finalize(stmt);
+        return nullptr;
+      }
+      result = new_result;
+    }
+    strcat(result, record);
+    result_size += record_len;
+    first_record = 0;
+  }
+
+  if (rc != SQLITE_DONE) {
+    fprintf(stderr, "Error reading data: %s\n", sqlite3_errmsg(db));
+    free(result);
+    sqlite3_finalize(stmt);
+    return NULL;
+  }
+  strcat(result, "]");
+  sqlite3_finalize(stmt);
+  pthread_mutex_unlock(&db_mutex);
+  return result;
+}