Add delay load samples (#2839)

.github/workflows/clippy.yml

@@ -50,6 +50,8 @@ jobs:
           cargo clippy -p sample_credentials &&
           cargo clippy -p sample_data_protection &&
           cargo clippy -p sample_dcomp &&
+          cargo clippy -p sample_delay_load &&
+          cargo clippy -p sample_delay_load_sys &&
           cargo clippy -p sample_device_watcher &&
           cargo clippy -p sample_direct2d &&
           cargo clippy -p sample_direct3d12 &&

.github/workflows/test.yml

@@ -57,6 +57,8 @@ jobs:
           cargo test -p sample_credentials &&
           cargo test -p sample_data_protection &&
           cargo test -p sample_dcomp &&
+          cargo test -p sample_delay_load &&
+          cargo test -p sample_delay_load_sys &&
           cargo test -p sample_device_watcher &&
           cargo test -p sample_direct2d &&
           cargo test -p sample_direct3d12 &&
@@ -103,8 +105,8 @@ jobs:
           cargo test -p test_debugger_visualizer &&
           cargo test -p test_deprecated &&
           cargo test -p test_dispatch &&
-          cargo test -p test_does_not_return &&
           cargo clean &&
+          cargo test -p test_does_not_return &&
           cargo test -p test_enums &&
           cargo test -p test_error &&
           cargo test -p test_event &&

crates/samples/windows-sys/delay_load/Cargo.toml

@@ -0,0 +1,11 @@
+[package]
+name = "sample_delay_load_sys"
+version = "0.0.0"
+edition = "2021"
+publish = false
+
+[dependencies.windows-sys]
+path = "../../../libs/sys"
+features = [
+    "Win32_System_LibraryLoader",
+]

crates/samples/windows-sys/delay_load/src/main.rs

@@ -0,0 +1,41 @@
+use windows_sys::{core::*, Win32::Foundation::*, Win32::System::LibraryLoader::*};
+
+/// # Safety
+///
+/// The `PCSTR` parameters need to be valid for reads up until and including the next `\0`.
+pub unsafe fn delay_load<T>(library: PCSTR, function: PCSTR) -> Option<T> {
+    let library = LoadLibraryExA(library, 0, LOAD_LIBRARY_SEARCH_DEFAULT_DIRS);
+
+    if library == 0 {
+        return None;
+    }
+
+    let address = GetProcAddress(library, function);
+
+    if address.is_some() {
+        return Some(std::mem::transmute_copy(&address));
+    }
+
+    FreeLibrary(library);
+    None
+}
+
+fn main() {
+    unsafe {
+        if let Some(api) = delay_load::<ShellMessageBoxW>(s!("shlwapi.dll"), s!("ShellMessageBoxW"))
+        {
+            api(0, 0, w!("Message"), w!("Sample"), 1);
+        } else {
+            println!("Can't find API");
+        }
+    }
+}
+
+type ShellMessageBoxW = unsafe extern "cdecl" fn(
+    happinst: usize,
+    hwnd: usize,
+    lpctext: PCWSTR,
+    lpctitle: PCWSTR,
+    fustyle: u32,
+    ...
+) -> i32;

crates/samples/windows/delay_load/Cargo.toml

@@ -0,0 +1,11 @@
+[package]
+name = "sample_delay_load"
+version = "0.0.0"
+edition = "2021"
+publish = false
+
+[dependencies.windows]
+path = "../../../libs/windows"
+features = [
+    "Win32_System_LibraryLoader",
+]

crates/samples/windows/delay_load/src/main.rs

@@ -0,0 +1,41 @@
+use windows::{core::*, Win32::Foundation::*, Win32::System::LibraryLoader::*};
+
+/// # Safety
+///
+/// The `PCSTR` parameters need to be valid for reads up until and including the next `\0`.
+pub unsafe fn delay_load<T>(library: PCSTR, function: PCSTR) -> Option<T> {
+    let library = LoadLibraryExA(library, None, LOAD_LIBRARY_SEARCH_DEFAULT_DIRS);
+
+    let Ok(library) = library else {
+        return None;
+    };
+
+    let address = GetProcAddress(library, function);
+
+    if address.is_some() {
+        return Some(std::mem::transmute_copy(&address));
+    }
+
+    _ = FreeLibrary(library);
+    None
+}
+
+fn main() {
+    unsafe {
+        if let Some(api) = delay_load::<ShellMessageBoxW>(s!("shlwapi.dll"), s!("ShellMessageBoxW"))
+        {
+            api(0, 0, w!("Message"), w!("Sample"), 1);
+        } else {
+            println!("Can't find API");
+        }
+    }
+}
+
+type ShellMessageBoxW = unsafe extern "cdecl" fn(
+    happinst: usize,
+    hwnd: usize,
+    lpctext: PCWSTR,
+    lpctitle: PCWSTR,
+    fustyle: u32,
+    ...
+) -> i32;