From 60f9e456952f9ef46aaf603cdde0a05e2e8a7de7 Mon Sep 17 00:00:00 2001
From: Kenny Kerr <kenny@kennykerr.ca>
Date: Mon, 15 Jan 2024 10:01:48 -0600
Subject: [PATCH] Expand WMI sample for `ExecQuery` and `ExecMethod` (#2794)

---
 crates/libs/core/src/strings/bstr.rs   | 20 ++++++--
 crates/libs/core/src/variant.rs        | 12 +++++
 crates/samples/windows/wmi/src/main.rs | 65 +++++++++++++++++++-------
 crates/tests/variant/tests/tests.rs    |  2 +
 4 files changed, 77 insertions(+), 22 deletions(-)

diff --git a/crates/libs/core/src/strings/bstr.rs b/crates/libs/core/src/strings/bstr.rs
index 13a06138f2..91197ebd12 100644
--- a/crates/libs/core/src/strings/bstr.rs
+++ b/crates/libs/core/src/strings/bstr.rs
@@ -29,11 +29,17 @@ impl BSTR {
 
     /// Get the string as 16-bit wide characters (wchars).
     pub fn as_wide(&self) -> &[u16] {
-        if self.0.is_null() {
-            return &[];
-        }
+        unsafe { std::slice::from_raw_parts(self.as_ptr(), self.len()) }
+    }
 
-        unsafe { std::slice::from_raw_parts(self.0, self.len()) }
+    /// Returns a raw pointer to the `BSTR` buffer.
+    pub fn as_ptr(&self) -> *const u16 {
+        if !self.is_empty() {
+            self.0
+        } else {
+            const EMPTY: [u16; 1] = [0];
+            EMPTY.as_ptr()
+        }
     }
 
     /// Create a `BSTR` from a slice of 16 bit characters (wchars).
@@ -105,6 +111,12 @@ impl TryFrom<BSTR> for String {
     }
 }
 
+impl IntoParam<PCWSTR> for &BSTR {
+    unsafe fn into_param(self) -> Param<PCWSTR> {
+        Param::Owned(PCWSTR(self.as_ptr()))
+    }
+}
+
 impl Default for BSTR {
     fn default() -> Self {
         Self(std::ptr::null_mut())
diff --git a/crates/libs/core/src/variant.rs b/crates/libs/core/src/variant.rs
index b8fdedd2d2..e7885ee30a 100644
--- a/crates/libs/core/src/variant.rs
+++ b/crates/libs/core/src/variant.rs
@@ -84,6 +84,18 @@ impl std::fmt::Debug for PROPVARIANT {
     }
 }
 
+impl std::fmt::Display for VARIANT {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        std::write!(f, "{}", BSTR::try_from(self).unwrap_or_default())
+    }
+}
+
+impl std::fmt::Display for PROPVARIANT {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        std::write!(f, "{}", BSTR::try_from(self).unwrap_or_default())
+    }
+}
+
 impl PartialEq for VARIANT {
     fn eq(&self, other: &Self) -> bool {
         unsafe {
diff --git a/crates/samples/windows/wmi/src/main.rs b/crates/samples/windows/wmi/src/main.rs
index a7c4553a45..3397885517 100644
--- a/crates/samples/windows/wmi/src/main.rs
+++ b/crates/samples/windows/wmi/src/main.rs
@@ -1,7 +1,4 @@
-use windows::{
-    core::*, Win32::System::Com::*, Win32::System::Ole::*, Win32::System::Variant::*,
-    Win32::System::Wmi::*,
-};
+use windows::{core::*, Win32::System::Com::*, Win32::System::Wmi::*};
 
 fn main() -> Result<()> {
     unsafe {
@@ -24,6 +21,10 @@ fn main() -> Result<()> {
         let server =
             locator.ConnectServer(&BSTR::from("root\\cimv2"), None, None, None, 0, None, None)?;
 
+        //
+        // ExecQuery example
+        //
+
         let query = server.ExecQuery(
             &BSTR::from("WQL"),
             &BSTR::from("select Caption from Win32_LogicalDisk"),
@@ -37,26 +38,54 @@ fn main() -> Result<()> {
             query.Next(WBEM_INFINITE, &mut row, &mut returned).ok()?;
 
             if let Some(row) = &row[0] {
-                let mut value = Default::default();
+                let mut value = VARIANT::default();
                 row.Get(w!("Caption"), 0, &mut value, None, None)?;
-                println!(
-                    "{}",
-                    VarFormat(
-                        &value,
-                        None,
-                        VARFORMAT_FIRST_DAY_SYSTEMDEFAULT,
-                        VARFORMAT_FIRST_WEEK_SYSTEMDEFAULT,
-                        0
-                    )?
-                );
-
-                // TODO: workaround for https://github.com/microsoft/windows-rs/issues/539
-                VariantClear(&mut value)?;
+                println!("{value}",);
             } else {
                 break;
             }
         }
 
+        //
+        // ExecMethod example
+        //
+
+        let class_name = BSTR::from("Win32_Process");
+        let method_name = BSTR::from("Create");
+
+        let mut class = None;
+        server.GetObject(
+            &class_name,
+            Default::default(),
+            None,
+            Some(&mut class),
+            None,
+        )?;
+        let class = class.unwrap();
+
+        let mut input = None;
+        class.GetMethod(&method_name, 0, &mut input, std::ptr::null_mut())?;
+        let input = input.unwrap();
+
+        let object = input.SpawnInstance(0)?;
+        object.Put(w!("CommandLine"), 0, &VARIANT::from("notepad.exe"), 0)?;
+
+        let mut output = None;
+        server.ExecMethod(
+            &class_name,
+            &method_name,
+            Default::default(),
+            None,
+            &object,
+            Some(&mut output),
+            None,
+        )?;
+        let output = output.unwrap();
+
+        let mut value = VARIANT::default();
+        output.Get(w!("ReturnValue"), 0, &mut value, None, None)?;
+        println!("`Create` method return value: {value}");
+
         Ok(())
     }
 }
diff --git a/crates/tests/variant/tests/tests.rs b/crates/tests/variant/tests/tests.rs
index 9a7a558632..b348a15cc6 100644
--- a/crates/tests/variant/tests/tests.rs
+++ b/crates/tests/variant/tests/tests.rs
@@ -103,6 +103,7 @@ fn test_variant() -> Result<()> {
     assert_eq!(BSTR::try_from(&v)?, "3.5");
 
     assert_eq!(format!("{v:?}"), "VARIANT { type: 5, value: 3.5 }");
+    assert_eq!(format!("{v}"), "3.5");
 
     let clone = v.clone();
     assert_eq!(v, clone);
@@ -219,6 +220,7 @@ fn test_propvariant() -> Result<()> {
     assert_eq!(BSTR::try_from(&v)?, "3.5");
 
     assert_eq!(format!("{v:?}"), "PROPVARIANT { type: 5, value: 3.5 }");
+    assert_eq!(format!("{v}"), "3.5");
 
     let clone = v.clone();
     assert_eq!(v, clone);