Add language and database properties (#10)

.vscode/cspell.json

@@ -3,8 +3,8 @@
   "language": "en",
   "words": [
     "cdylib",
-
     "INSTALLMESSAGE",
+    "LANGID",
     "LPCSTR",
     "LPSTR",
     "msbuild",

src/database.rs

@@ -0,0 +1,15 @@
+// Copyright 2022 Heath Stewart.
+// Licensed under the MIT License. See LICENSE.txt in the project root for license information.
+
+use super::{MSIHANDLE, PMSIHANDLE};
+
+/// The database for the current install session.
+pub struct Database {
+    h: PMSIHANDLE,
+}
+
+impl From<MSIHANDLE> for Database {
+    fn from(h: MSIHANDLE) -> Self {
+        Database { h: h.to_owned() }
+    }
+}

src/ffi.rs

@@ -25,6 +25,10 @@ extern "C" {
     #[link_name = "MsiDoActionA"]
     pub fn MsiDoAction(hInstall: MSIHANDLE, szAction: LPCSTR) -> u32;
 
+    pub fn MsiGetActiveDatabase(hInstall: MSIHANDLE) -> MSIHANDLE;
+
+    pub fn MsiGetLanguage(hInstall: MSIHANDLE) -> u16;
+
     pub fn MsiGetLastErrorRecord() -> MSIHANDLE;
 
     pub fn MsiGetMode(hInstall: MSIHANDLE, eRunMode: RunMode) -> BOOL;

src/lib.rs

@@ -10,10 +10,12 @@ compile_error!("supported on windows only");
 
 // See https://docs.microsoft.com/windows/win32/msi/automation-interface-reference
 
+mod database;
 mod ffi;
 mod record;
 mod session;
 
+pub use database::Database;
 pub use ffi::{
     ERROR_FUNCTION_NOT_CALLED, ERROR_INSTALL_FAILURE, ERROR_INSTALL_USEREXIT, ERROR_NO_MORE_ITEMS,
     ERROR_SUCCESS,

src/session.rs

@@ -2,7 +2,7 @@
 // Licensed under the MIT License. See LICENSE.txt in the project root for license information.
 
 use super::ffi;
-use super::{MessageType, Record, RunMode, MSIHANDLE};
+use super::{Database, MessageType, Record, RunMode, MSIHANDLE};
 use std::ffi::CString;
 use std::ops::Deref;
 
@@ -27,10 +27,16 @@ use std::ops::Deref;
 /// ```
 pub struct Session {
     h: MSIHANDLE,
-    owned: bool,
 }
 
 impl Session {
+    /// Returns the active database for the installation. This function returns a read-only [`Database`].
+    pub fn database(&self) -> Database {
+        unsafe {
+            let h = ffi::MsiGetActiveDatabase(self.h);
+            Database::from(h)
+        }
+    }
     /// Runs the specified immediate custom action, or schedules a deferred custom action.
     /// If `None` the default action is run e.g., `INSTALL`.
     ///
@@ -77,6 +83,11 @@ impl Session {
         self.do_action(Some(action));
     }
 
+    /// The numeric language ID used by the current install session.
+    pub fn language(&self) -> u16 {
+        unsafe { ffi::MsiGetLanguage(self.h) }
+    }
+
     /// Processes a [`Record`] within the [`Session`].
     pub fn message(&self, kind: MessageType, record: &Record) -> i32 {
         unsafe { ffi::MsiProcessMessage(self.h, kind, **record) }
@@ -168,20 +179,8 @@ impl Deref for Session {
     }
 }
 
-impl Drop for Session {
-    fn drop(&mut self) {
-        // An MSIHANDLE must be closed when it was created by opening a package,
-        // but not closed when it was passed to a custom action.
-        if self.owned {
-            unsafe {
-                ffi::MsiCloseHandle(self.h);
-            }
-        }
-    }
-}
-
 impl From<MSIHANDLE> for Session {
     fn from(h: MSIHANDLE) -> Self {
-        Session { h, owned: false }
+        Session { h }
     }
 }