1 files changed, 111 insertions, 0 deletions
diff --git a/third_party/rust/uniffi_bindgen/src/bindings/kotlin/templates/ErrorTemplate.kt b/third_party/rust/uniffi_bindgen/src/bindings/kotlin/templates/ErrorTemplate.kt
new file mode 100644
index 0000000000..986db5424d
--- /dev/null
+++ b/third_party/rust/uniffi_bindgen/src/bindings/kotlin/templates/ErrorTemplate.kt
@@ -0,0 +1,111 @@
+{%- let type_name = type_|type_name(ci) %}
+{%- let ffi_converter_name = type_|ffi_converter_name %}
+{%- let canonical_type_name = type_|canonical_name %}
+
+{% if e.is_flat() %}
+sealed class {{ type_name }}(message: String): Exception(message){% if contains_object_references %}, Disposable {% endif %} {
+        // Each variant is a nested class
+        // Flat enums carries a string error message, so no special implementation is necessary.
+        {% for variant in e.variants() -%}
+        class {{ variant|error_variant_name }}(message: String) : {{ type_name }}(message)
+        {% endfor %}
+
+    companion object ErrorHandler : CallStatusErrorHandler<{{ type_name }}> {
+        override fun lift(error_buf: RustBuffer.ByValue): {{ type_name }} = {{ ffi_converter_name }}.lift(error_buf)
+    }
+}
+{%- else %}
+sealed class {{ type_name }}: Exception(){% if contains_object_references %}, Disposable {% endif %} {
+    // Each variant is a nested class
+    {% for variant in e.variants() -%}
+    {%- let variant_name = variant|error_variant_name %}
+    class {{ variant_name }}(
+        {% for field in variant.fields() -%}
+        val {{ field.name()|var_name }}: {{ field|type_name(ci) }}{% if loop.last %}{% else %}, {% endif %}
+        {% endfor -%}
+    ) : {{ type_name }}() {
+        override val message
+            get() = "{%- for field in variant.fields() %}{{ field.name()|var_name|unquote }}=${ {{field.name()|var_name }} }{% if !loop.last %}, {% endif %}{% endfor %}"
+    }
+    {% endfor %}
+
+    companion object ErrorHandler : CallStatusErrorHandler<{{ type_name }}> {
+        override fun lift(error_buf: RustBuffer.ByValue): {{ type_name }} = {{ ffi_converter_name }}.lift(error_buf)
+    }
+
+    {% if contains_object_references %}
+    @Suppress("UNNECESSARY_SAFE_CALL") // codegen is much simpler if we unconditionally emit safe calls here
+    override fun destroy() {
+        when(this) {
+            {%- for variant in e.variants() %}
+            is {{ type_name }}.{{ variant|error_variant_name }} -> {
+                {%- if variant.has_fields() %}
+                {% call kt::destroy_fields(variant) %}
+                {% else -%}
+                // Nothing to destroy
+                {%- endif %}
+            }
+            {%- endfor %}
+        }.let { /* this makes the `when` an expression, which ensures it is exhaustive */ }
+    }
+    {% endif %}
+}
+{%- endif %}
+
+public object {{ e|ffi_converter_name }} : FfiConverterRustBuffer<{{ type_name }}> {
+    override fun read(buf: ByteBuffer): {{ type_name }} {
+        {% if e.is_flat() %}
+            return when(buf.getInt()) {
+            {%- for variant in e.variants() %}
+            {{ loop.index }} -> {{ type_name }}.{{ variant|error_variant_name }}({{ Type::String.borrow()|read_fn }}(buf))
+            {%- endfor %}
+            else -> throw RuntimeException("invalid error enum value, something is very wrong!!")
+        }
+        {% else %}
+
+        return when(buf.getInt()) {
+            {%- for variant in e.variants() %}
+            {{ loop.index }} -> {{ type_name }}.{{ variant|error_variant_name }}({% if variant.has_fields() %}
+                {% for field in variant.fields() -%}
+                {{ field|read_fn }}(buf),
+                {% endfor -%}
+            {%- endif -%})
+            {%- endfor %}
+            else -> throw RuntimeException("invalid error enum value, something is very wrong!!")
+        }
+        {%- endif %}
+    }
+
+    override fun allocationSize(value: {{ type_name }}): Int {
+        {%- if e.is_flat() %}
+        return 4
+        {%- else %}
+        return when(value) {
+            {%- for variant in e.variants() %}
+            is {{ type_name }}.{{ variant|error_variant_name }} -> (
+                // Add the size for the Int that specifies the variant plus the size needed for all fields
+                4
+                {%- for field in variant.fields() %}
+                + {{ field|allocation_size_fn }}(value.{{ field.name()|var_name }})
+                {%- endfor %}
+            )
+            {%- endfor %}
+        }
+        {%- endif %}
+    }
+
+    override fun write(value: {{ type_name }}, buf: ByteBuffer) {
+        when(value) {
+            {%- for variant in e.variants() %}
+            is {{ type_name }}.{{ variant|error_variant_name }} -> {
+                buf.putInt({{ loop.index }})
+                {%- for field in variant.fields() %}
+                {{ field|write_fn }}(value.{{ field.name()|var_name }}, buf)
+                {%- endfor %}
+                Unit
+            }
+            {%- endfor %}
+        }.let { /* this makes the `when` an expression, which ensures it is exhaustive */ }
+    }
+
+}