write shit

wfassoc/src/lib.rs

@@ -28,7 +28,9 @@ pub enum Error {
 
 // endregion
 
-/// The scope where wfassoc will operate.
+// region: Basic Types
+
+/// The scope where wfassoc will register and unregister.
 #[derive(Debug, Copy, Clone)]
 pub enum Scope {
     /// Scope for current user.
@@ -37,6 +39,18 @@ pub enum Scope {
     System,
 }
 
+/// The view when wfassoc querying infomations.
+#[derive(Debug, Copy, Clone)]
+pub enum View {
+    /// The view of current user.
+    User,
+    /// The view of system.
+    System,
+    /// Hybrid view of User and System.
+    /// It can be seen as that we use System first and then use User to override any existing items.
+    Hybrid,
+}
+
 /// Check whether current process has administrative privilege.
 ///
 /// It usually means that checking whether current process is running as Administrator.
@@ -90,10 +104,13 @@ pub fn has_privilege() -> bool {
     is_member != 0
 }
 
+// endregion
+
 // region: File Extension
 
 /// The struct representing an file extension which must start with dot (`.`)
 /// and followed by at least one arbitrary characters.
+#[derive(Debug, Clone)]
 pub struct FileExt {
     /// The body of file extension (excluding dot).
     inner: String,
@@ -110,14 +127,14 @@ impl FileExt {
         }
     }
 
-    pub fn query(&self, scope: Scope) -> Option<FileExtAssoc> {
-        FileExtAssoc::new(self, scope)
+    pub fn query(&self, view: View) -> Option<FileExtAssoc> {
+        FileExtAssoc::new(self, view)
     }
 }
 
 /// The error occurs when try parsing string into FileExt.
 #[derive(Debug, TeError)]
-#[error("given file extension name is illegal")]
+#[error("given file extension is illegal")]
 pub struct ParseFileExtError {}
 
 impl ParseFileExtError {
@@ -141,34 +158,44 @@ impl FromStr for FileExt {
 }
 
 /// The association infomations of specific file extension.
+#[derive(Debug)]
 pub struct FileExtAssoc {
     default: String,
     open_with_progids: Vec<String>,
 }
 
 impl FileExtAssoc {
-    fn new(file_ext: &FileExt, scope: Scope) -> Option<Self> {
-        let hk = match scope {
-            Scope::User => winreg::RegKey::predef(winreg::enums::HKEY_CURRENT_USER),
-            Scope::System => winreg::RegKey::predef(winreg::enums::HKEY_LOCAL_MACHINE),
-        };
-        let classes = hk
-            .open_subkey_with_flags("Software\\Classes", winreg::enums::KEY_READ)
-            .unwrap();
-        let thisext =
-            match classes.open_subkey_with_flags(file_ext.to_string(), winreg::enums::KEY_READ) {
-                Ok(v) => v,
-                Err(e) => return None,
-            };
+    fn new(file_ext: &FileExt, view: View) -> Option<Self> {
+        use winreg::RegKey;
+        use winreg::enums::{HKEY_CLASSES_ROOT, HKEY_CURRENT_USER, HKEY_LOCAL_MACHINE, KEY_READ};
 
-        let default = thisext.get_value("").unwrap_or(String::new());
-        let open_with_progids = if let Ok(progids) =
-            thisext.open_subkey_with_flags("OpenWithProdIds", winreg::enums::KEY_READ)
-        {
-            progids.enum_keys().map(|x| x.unwrap()).collect()
-        } else {
-            Vec::new()
+        // navigate to extension container
+        let hk = match view {
+            View::User => RegKey::predef(HKEY_CURRENT_USER),
+            View::System => RegKey::predef(HKEY_LOCAL_MACHINE),
+            View::Hybrid => RegKey::predef(HKEY_CLASSES_ROOT),
         };
+        let classes = match view {
+            View::User | View::System => hk
+                .open_subkey_with_flags("Software\\Classes", KEY_READ)
+                .unwrap(),
+            View::Hybrid => hk.open_subkey_with_flags("", KEY_READ).unwrap(),
+        };
+
+        // open extension key if possible
+        let thisext = match classes.open_subkey_with_flags(file_ext.to_string(), KEY_READ) {
+            Ok(v) => v,
+            Err(_) => return None,
+        };
+
+        // fetch extension infos.
+        let default = thisext.get_value("").unwrap_or(String::new());
+        let open_with_progids =
+            if let Ok(progids) = thisext.open_subkey_with_flags("OpenWithProdIds", KEY_READ) {
+                progids.enum_keys().map(|x| x.unwrap()).filter(|k| !k.is_empty()).collect()
+            } else {
+                Vec::new()
+            };
 
         Some(Self {
             default,