Add last_error_record function (#9)

src/ffi.rs

@@ -25,6 +25,8 @@ extern "C" {
     #[link_name = "MsiDoActionA"]
     pub fn MsiDoAction(hInstall: MSIHANDLE, szAction: LPCSTR) -> u32;
 
+    pub fn MsiGetLastErrorRecord() -> MSIHANDLE;
+
     pub fn MsiGetMode(hInstall: MSIHANDLE, eRunMode: RunMode) -> BOOL;
 
     #[link_name = "MsiGetPropertyA"]

src/lib.rs

@@ -71,6 +71,26 @@ pub enum RunMode {
     Commit = 18,
 }
 
+/// Gets the last Windows Installer error for the current process.
+///
+/// # Example
+///
+/// ```
+/// use msica::*;
+///
+/// if let Some(error) = last_error_record() {
+///     println!("last error: {}", error.format_text());
+/// }
+/// ```
+pub fn last_error_record() -> Option<Record> {
+    unsafe {
+        match ffi::MsiGetLastErrorRecord() {
+            h if !h.is_null() => Some(h.into()),
+            _ => None,
+        }
+    }
+}
+
 /// A Windows Installer handle. This handle is not automatically closed.
 #[derive(Clone, Copy)]
 #[repr(transparent)]
@@ -84,6 +104,10 @@ impl MSIHANDLE {
     fn to_owned(&self) -> PMSIHANDLE {
         PMSIHANDLE(*self)
     }
+
+    fn is_null(&self) -> bool {
+        self.0 == 0
+    }
 }
 
 impl From<u32> for MSIHANDLE {

src/record.rs

@@ -263,6 +263,12 @@ impl Deref for Record {
     }
 }
 
+impl From<MSIHANDLE> for Record {
+    fn from(h: MSIHANDLE) -> Self {
+        Record { h: h.to_owned() }
+    }
+}
+
 impl From<&str> for Record {
     fn from(s: &str) -> Self {
         unsafe {