1 files changed, 54 insertions, 0 deletions
diff --git a/validator_derive/src/asserts.rs b/validator_derive/src/asserts.rs
new file mode 100644
index 0000000..65db5cf
--- /dev/null
+++ b/validator_derive/src/asserts.rs
@@ -0,0 +1,54 @@
+
+pub static NUMBER_TYPES: [&'static str; 24] = [
+    "usize", "u8", "u16", "u32", "u64",
+    "isize", "i8", "i16", "i32", "i64",
+    "f32", "f64",
+
+    "Option<usize>", "Option<u8>", "Option<u16>", "Option<u32>", "Option<u64>",
+    "Option<isize>", "Option<i8>", "Option<i16>", "Option<i32>", "Option<i64>",
+    "Option<f32>", "Option<f64>",
+];
+
+
+pub fn assert_string_type(name: &str, field_type: &String) {
+    if field_type != "String"
+        && field_type != "&str"
+        && field_type != "Option<String>"
+        && !(field_type.starts_with("Option<") && field_type.ends_with("str>")) {
+        panic!("`{}` validator can only be used on String, &str or an Option of those", name);
+    }
+}
+
+pub fn assert_type_matches(field_name: String, field_type: &String, field_type2: Option<&String>) {
+    if let Some(t2) = field_type2 {
+        if field_type != t2 {
+            panic!("Invalid argument for `must_match` validator of field `{}`: types of field can't match", field_name);
+        }
+    } else {
+        panic!("Invalid argument for `must_match` validator of field `{}`: the other field doesn't exist in struct", field_name);
+    }
+}
+
+pub fn assert_has_len(field_name: String, field_type: &String) {
+    if field_type != "String"
+        && !field_type.starts_with("Vec<")
+        && !field_type.starts_with("Option<Vec<")
+        && field_type != "Option<String>"
+        // a bit ugly
+        && !(field_type.starts_with("Option<") && field_type.ends_with("str>"))
+        && field_type != "&str" {
+            panic!(
+                "Validator `length` can only be used on types `String`, `&str` or `Vec` but found `{}` for field `{}`",
+                field_type, field_name
+            );
+    }
+}
+
+pub fn assert_has_range(field_name: String, field_type: &String) {
+    if !NUMBER_TYPES.contains(&field_type.as_ref()) {
+        panic!(
+            "Validator `range` can only be used on number types but found `{}` for field `{}`",
+            field_type, field_name
+        );
+    }
+}