Use a singleton for COMLibrary to fix issue #139 (#143)

Cargo.toml

@@ -42,7 +42,7 @@ num_cpus = "1.13.1"
 
 [target.'cfg(target_os = "windows")'.dependencies]
 local-ip-address = "0.4.4"
-wmi = "0.11.0"
+wmi = "0.12.0"
 winreg = "0.10.1"
 windows = { version = "0.39.0", features = [
       "Win32_Foundation",

src/windows/mod.rs

@@ -3,6 +3,7 @@ use std::collections::HashMap;
 use std::path::PathBuf;
 use winreg::enums::*;
 use winreg::RegKey;
+use wmi::WMIResult;
 use wmi::{COMLibrary, Variant, WMIConnection};
 
 use windows::{
@@ -148,6 +149,15 @@ impl WindowsMemoryReadout {
     }
 }
 
+thread_local! {
+    static COM_LIB: COMLibrary = COMLibrary::new().unwrap();
+}
+
+fn wmi_connection() -> WMIResult<WMIConnection> {
+    let com_lib = COM_LIB.with(|com| *com);
+    WMIConnection::new(com_lib)
+}
+
 pub struct WindowsGeneralReadout;
 
 impl GeneralReadout for WindowsGeneralReadout {
@@ -310,8 +320,7 @@ impl GeneralReadout for WindowsGeneralReadout {
     }
 
     fn os_name(&self) -> Result<String, ReadoutError> {
-        let com_con = COMLibrary::new()?;
-        let wmi_con = WMIConnection::new(com_con)?;
+        let wmi_con = wmi_connection()?;
 
         let results: Vec<HashMap<String, Variant>> =
             wmi_con.raw_query("SELECT Caption FROM Win32_OperatingSystem")?;