refactor(vulkan-ffi): extract surface bootstrap module

adapters/fparkan-render-vulkan/src/ffi/surface.rs

@@ -0,0 +1,159 @@
+#![allow(unsafe_code)]
+
+use ash::{khr::surface, vk};
+use fparkan_platform::NativeWindowHandles;
+use serde::Serialize;
+use std::ffi::CStr;
+use std::os::raw::c_char;
+
+use super::VulkanInstanceProbe;
+use crate::policy::serialize_json_or_fallback;
+
+/// Deterministic Vulkan surface creation plan.
+#[derive(Clone, Debug, Eq, PartialEq)]
+pub struct VulkanSurfacePlan {
+    /// Report schema version.
+    pub schema: u32,
+    /// Instance extensions required by the native display backend.
+    pub required_instance_extensions: Vec<String>,
+}
+
+/// Vulkan surface bootstrap error.
+#[derive(Clone, Debug, Eq, PartialEq)]
+pub enum VulkanSurfaceError {
+    /// No native raw window/display handles were available.
+    MissingNativeHandles,
+    /// Required platform surface extensions could not be enumerated.
+    RequiredExtensionsFailed {
+        /// Vulkan result.
+        result: vk::Result,
+    },
+    /// A required extension pointer was not valid UTF-8.
+    InvalidExtensionName,
+    /// Surface creation failed.
+    CreateFailed {
+        /// Vulkan result.
+        result: vk::Result,
+    },
+}
+
+impl std::fmt::Display for VulkanSurfaceError {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        match self {
+            Self::MissingNativeHandles => {
+                write!(
+                    f,
+                    "native window/display handles are required for Vulkan surface creation"
+                )
+            }
+            Self::RequiredExtensionsFailed { result } => write!(
+                f,
+                "failed to enumerate required Vulkan surface extensions: {result:?}"
+            ),
+            Self::InvalidExtensionName => {
+                write!(f, "Vulkan surface extension name is not valid UTF-8")
+            }
+            Self::CreateFailed { result } => {
+                write!(f, "Vulkan surface creation failed: {result:?}")
+            }
+        }
+    }
+}
+
+impl std::error::Error for VulkanSurfaceError {}
+
+/// Created Vulkan surface probe.
+pub struct VulkanSurfaceProbe {
+    pub(super) loader: surface::Instance,
+    pub(super) surface: vk::SurfaceKHR,
+    /// Deterministic surface creation report.
+    pub report: VulkanSurfacePlan,
+}
+
+impl Drop for VulkanSurfaceProbe {
+    fn drop(&mut self) {
+        // SAFETY: The `SurfaceKHR` was created by this probe and is destroyed once during drop.
+        unsafe { self.loader.destroy_surface(self.surface, None) };
+    }
+}
+
+/// Builds a deterministic Vulkan surface plan from native window handles.
+///
+/// # Errors
+///
+/// Returns [`VulkanSurfaceError`] when no native handles exist or the platform
+/// display backend has no Vulkan surface extension mapping.
+pub fn plan_vulkan_surface(
+    handles: Option<NativeWindowHandles>,
+) -> Result<VulkanSurfacePlan, VulkanSurfaceError> {
+    let handles = handles.ok_or(VulkanSurfaceError::MissingNativeHandles)?;
+    let required = ash_window::enumerate_required_extensions(handles.display)
+        .map_err(|error| VulkanSurfaceError::RequiredExtensionsFailed { result: error })?;
+    let mut required_instance_extensions = Vec::with_capacity(required.len());
+    for extension in required {
+        let name = extension_name(*extension)?;
+        required_instance_extensions.push(name);
+    }
+    required_instance_extensions.sort();
+    required_instance_extensions.dedup();
+    Ok(VulkanSurfacePlan {
+        schema: 1,
+        required_instance_extensions,
+    })
+}
+
+/// Creates a Vulkan surface probe from native window handles.
+///
+/// # Errors
+///
+/// Returns [`VulkanSurfaceError`] when handles are missing, required extensions
+/// cannot be planned, or `vkCreate*SurfaceKHR` fails.
+pub fn create_vulkan_surface_probe(
+    instance: &VulkanInstanceProbe,
+    handles: Option<NativeWindowHandles>,
+) -> Result<VulkanSurfaceProbe, VulkanSurfaceError> {
+    let handles = handles.ok_or(VulkanSurfaceError::MissingNativeHandles)?;
+    let report = plan_vulkan_surface(Some(handles))?;
+    // SAFETY: The platform handles are only used to create a child surface owned by this probe.
+    let surface = unsafe {
+        ash_window::create_surface(
+            &instance.entry,
+            &instance.instance,
+            handles.display,
+            handles.window,
+            None,
+        )
+    }
+    .map_err(|error| VulkanSurfaceError::CreateFailed { result: error })?;
+    Ok(VulkanSurfaceProbe {
+        loader: surface::Instance::new(&instance.entry, &instance.instance),
+        surface,
+        report,
+    })
+}
+
+/// Renders a deterministic JSON Vulkan surface plan.
+#[must_use]
+pub fn render_surface_plan_json(plan: &VulkanSurfacePlan) -> String {
+    #[derive(Serialize)]
+    struct SurfacePlanJson<'a> {
+        schema: u32,
+        required_instance_extensions: &'a [String],
+    }
+
+    serialize_json_or_fallback(
+        &SurfacePlanJson {
+            schema: plan.schema,
+            required_instance_extensions: &plan.required_instance_extensions,
+        },
+        "{\"schema\":0,\"required_instance_extensions\":[]}",
+    )
+}
+
+pub(super) fn extension_name(extension: *const c_char) -> Result<String, VulkanSurfaceError> {
+    // SAFETY: `ash-window` returns extension pointers to static NUL-terminated Vulkan names.
+    let name = unsafe { CStr::from_ptr(extension) };
+    name.to_str()
+        .map(str::to_string)
+        .map_err(|_| VulkanSurfaceError::InvalidExtensionName)
+}