Add UI layout XML automation

src/ui_core/layout_xml.cpp

@@ -0,0 +1,71 @@
+#include "ui_core/layout_xml.h"
+
+#include "ui_core/layout_value.h"
+
+#include <tinyxml2.h>
+
+namespace pp::ui {
+
+namespace {
+
+[[nodiscard]] pp::foundation::Status visit_element(const tinyxml2::XMLElement& element, LayoutParseSummary& summary)
+{
+    ++summary.node_count;
+
+    for (const char* name : { "width", "height" }) {
+        const char* value = element.Attribute(name);
+        if (value == nullptr) {
+            continue;
+        }
+
+        const auto length = parse_layout_length(value);
+        if (!length) {
+            return length.status();
+        }
+        ++summary.length_attribute_count;
+    }
+
+    for (const tinyxml2::XMLElement* child = element.FirstChildElement();
+         child != nullptr;
+         child = child->NextSiblingElement()) {
+        const auto status = visit_element(*child, summary);
+        if (!status.ok()) {
+            return status;
+        }
+    }
+
+    return pp::foundation::Status::success();
+}
+
+}
+
+pp::foundation::Result<LayoutParseSummary> parse_layout_xml(std::string_view xml)
+{
+    if (xml.empty()) {
+        return pp::foundation::Result<LayoutParseSummary>::failure(
+            pp::foundation::Status::invalid_argument("layout XML must not be empty"));
+    }
+
+    tinyxml2::XMLDocument document;
+    const auto error = document.Parse(xml.data(), xml.size());
+    if (error != tinyxml2::XML_SUCCESS) {
+        return pp::foundation::Result<LayoutParseSummary>::failure(
+            pp::foundation::Status::invalid_argument("layout XML could not be parsed"));
+    }
+
+    const tinyxml2::XMLElement* root = document.RootElement();
+    if (root == nullptr) {
+        return pp::foundation::Result<LayoutParseSummary>::failure(
+            pp::foundation::Status::invalid_argument("layout XML has no root element"));
+    }
+
+    LayoutParseSummary summary;
+    const auto status = visit_element(*root, summary);
+    if (!status.ok()) {
+        return pp::foundation::Result<LayoutParseSummary>::failure(status);
+    }
+
+    return pp::foundation::Result<LayoutParseSummary>::success(summary);
+}
+
+}