Implement copypasta::Load for macos::Clipboard

copypasta/Cargo.lock

@@ -1,4 +1,60 @@
 [root]
 name = "copypasta"
 version = "0.0.1"
+dependencies = [
+ "objc 0.2.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "objc-foundation 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "objc_id 0.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
+]
 
+[[package]]
+name = "block"
+version = "0.1.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+
+[[package]]
+name = "libc"
+version = "0.2.16"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+
+[[package]]
+name = "malloc_buf"
+version = "0.0.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "libc 0.2.16 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[[package]]
+name = "objc"
+version = "0.2.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "malloc_buf 0.0.6 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[[package]]
+name = "objc-foundation"
+version = "0.1.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "block 0.1.6 (registry+https://github.com/rust-lang/crates.io-index)",
+ "objc 0.2.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "objc_id 0.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[[package]]
+name = "objc_id"
+version = "0.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "objc 0.2.1 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[metadata]
+"checksum block 0.1.6 (registry+https://github.com/rust-lang/crates.io-index)" = "0d8c1fef690941d3e7788d328517591fecc684c084084702d6ff1641e993699a"
+"checksum libc 0.2.16 (registry+https://github.com/rust-lang/crates.io-index)" = "408014cace30ee0f767b1c4517980646a573ec61a57957aeeabcac8ac0a02e8d"
+"checksum malloc_buf 0.0.6 (registry+https://github.com/rust-lang/crates.io-index)" = "62bb907fe88d54d8d9ce32a3cceab4218ed2f6b7d35617cafe9adf84e43919cb"
+"checksum objc 0.2.1 (registry+https://github.com/rust-lang/crates.io-index)" = "7c9311aa5acd7bee14476afa0f0557f564e9d0d61218a8b833d9b1f871fa5fba"
+"checksum objc-foundation 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)" = "1add1b659e36c9607c7aab864a76c7a4c2760cd0cd2e120f3fb8b952c7e22bf9"
+"checksum objc_id 0.1.0 (registry+https://github.com/rust-lang/crates.io-index)" = "e4730aa1c64d722db45f7ccc4113a3e2c465d018de6db4d3e7dfe031e8c8a297"

copypasta/Cargo.toml

@@ -7,3 +7,8 @@ description = "Forthcoming clipboard library"
 keywords = ["clipboard", "copy", "paste"]
 
 [dependencies]
+
+[target.'cfg(target_os = "macos")'.dependencies]
+objc = "0.2"
+objc_id = "0.1"
+objc-foundation = "0.1"

copypasta/src/lib.rs

@@ -1,5 +1,9 @@
 //! A cross-platform clipboard library
 
+// This has to be here due to macro_use
+#[cfg(target_os = "macos")]
+#[macro_use] extern crate objc;
+
 /// Types that can get the system clipboard contents
 pub trait Load : Sized {
     /// Errors encountered when working with a clipboard. Each implementation is

copypasta/src/macos.rs

@@ -1,19 +1,243 @@
 //! Clipboard access on macOS
 //!
 //! Implemented according to https://developer.apple.com/library/content/documentation/Cocoa/Conceptual/PasteboardGuide106/Articles/pbReading.html#//apple_ref/doc/uid/TP40008123-SW1
-//!
-//! FIXME implement this :)
 
-struct Clipboard;
+mod ns {
+    extern crate objc_id;
+    extern crate objc_foundation;
 
-impl Load for Clipboard {
-    type Err = ();
+    #[link(name = "AppKit", kind = "framework")]
+    extern {}
+
+    use std::mem;
+
+    use objc::runtime::{Class, Object};
+    use self::objc_id::{Id, Owned};
+    use self::objc_foundation::{NSArray, NSObject, NSDictionary, NSString};
+    use self::objc_foundation::{INSString, INSArray, INSObject};
+
+    /// Rust API for NSPasteboard
+    pub struct Pasteboard(Id<Object>);
+
+    /// Errors occurring when creating a Pasteboard
+    #[derive(Debug)]
+    pub enum NewPasteboardError {
+        GetPasteboardClass,
+        LoadGeneralPasteboard,
+    }
+
+    /// Errors occurring when reading a string from the pasteboard
+    #[derive(Debug)]
+    pub enum ReadStringError {
+        GetStringClass,
+        ReadObjectsForClasses,
+    }
+
+    /// A trait for reading contents from the pasteboard
+    ///
+    /// This is intended to reflect the underlying objective C API
+    /// `readObjectsForClasses:options:`.
+    pub trait PasteboardReadObject<T> {
+        type Err;
+        fn read_object(&self) -> Result<T, Self::Err>;
+    }
+
+    impl PasteboardReadObject<String> for Pasteboard {
+        type Err = ReadStringError;
+        fn read_object(&self) -> Result<String, ReadStringError> {
+            // Get string class; need this for passing to readObjectsForClasses
+            let ns_string_class = match Class::get("NSString") {
+                Some(class) => class,
+                None => return Err(ReadStringError::GetStringClass),
+            };
+
+            let ns_string: Id<Object> = unsafe {
+                let ptr: *mut Object = msg_send![ns_string_class, class];
+
+                if ptr.is_null() {
+                    return Err(ReadStringError::GetStringClass);
+                } else {
+                    Id::from_ptr(ptr)
+                }
+            };
+
+            let classes: Id<NSArray<NSObject, Owned>> = unsafe {
+                // I think this transmute is valid. It's going from an Id<Object> to an
+                // Id<NSObject>. From transmute's perspective, the only thing that matters is that
+                // they both have the same size (they do for now since the generic is phantom data).
+                // In both cases, the underlying pointer is an id (from `[NSString class]`), so
+                // again, this should be valid. There's just nothing implemented in objc_id or
+                // objc_foundation to do this "safely". By the way, the only reason this is
+                // necessary is because INSObject isn't implemented for Id<Object>.
+                //
+                // And if that argument isn't convincing, my final reasoning is that "it seems to
+                // work".
+                NSArray::from_vec(vec![mem::transmute(ns_string)])
+            };
+
+            // No options
+            //
+            // Apparently this doesn't compile without a type hint, so it maps objects to objects!
+            let options: Id<NSDictionary<NSObject, NSObject>> = NSDictionary::new();
+
+            // call [pasteboard readObjectsForClasses:options:]
+            let copied_items = unsafe {
+                let copied_items: *mut NSArray<NSString> = msg_send![
+                    self.0,
+                    readObjectsForClasses:&*classes
+                    options:&*options
+                ];
+
+                if copied_items.is_null() {
+                    return Err(ReadStringError::ReadObjectsForClasses);
+                } else {
+                    Id::from_ptr(copied_items) as Id<NSArray<NSString>>
+                }
+            };
+
+            // Ok, this is great. We have an NSArray<NSString>, and these have decent bindings. Use
+            // the first item returned (if an item was returned) or just return an empty string
+            // XXX Should this return an error if no items were returned?
+            let contents = copied_items
+                .first_object()
+                .map(|ns_string| ns_string.as_str().to_owned())
+                .unwrap_or_else(String::new);
+
+            Ok(contents)
+        }
+    }
+
+    impl ::std::error::Error for ReadStringError {
+        fn description(&self) -> &str {
+            match *self {
+                ReadStringError::GetStringClass => "NSString class not found",
+                ReadStringError::ReadObjectsForClasses => "readObjectsForClasses:options: failed",
+            }
+        }
+    }
+
+    impl ::std::fmt::Display for ReadStringError {
+        fn fmt(&self, f: &mut ::std::fmt::Formatter) -> ::std::fmt::Result {
+            f.write_str(::std::error::Error::description(self))
+        }
+    }
+
+    impl ::std::error::Error for NewPasteboardError {
+        fn description(&self) -> &str {
+            match *self {
+                NewPasteboardError::GetPasteboardClass => {
+                    "NSPasteboard class not found"
+                },
+                NewPasteboardError::LoadGeneralPasteboard => {
+                    "[NSPasteboard generalPasteboard] failed"
+                },
+            }
+        }
+    }
+
+    impl ::std::fmt::Display for NewPasteboardError {
+        fn fmt(&self, f: &mut ::std::fmt::Formatter) -> ::std::fmt::Result {
+            f.write_str(::std::error::Error::description(self))
+        }
+    }
+
+    impl Pasteboard {
+        pub fn new() -> Result<Pasteboard, NewPasteboardError> {
+            // NSPasteboard *pasteboard = [NSPasteboard generalPasteboard];
+            let ns_pasteboard_class = match Class::get("NSPasteboard") {
+                Some(class) => class,
+                None => return Err(NewPasteboardError::GetPasteboardClass),
+            };
+
+            let ptr = unsafe {
+                let ptr: *mut Object = msg_send![ns_pasteboard_class, generalPasteboard];
+
+                if ptr.is_null() {
+                    return Err(NewPasteboardError::LoadGeneralPasteboard);
+                } else {
+                    ptr
+                }
+            };
+
+            let id = unsafe {
+                Id::from_ptr(ptr)
+            };
+
+            Ok(Pasteboard(id))
+        }
+    }
+}
+
+#[derive(Debug)]
+pub enum Error {
+    CreatePasteboard(ns::NewPasteboardError),
+    ReadString(ns::ReadStringError),
+}
+
+
+impl ::std::error::Error for Error {
+    fn cause(&self) -> Option<&::std::error::Error> {
+        match *self {
+            Error::CreatePasteboard(ref err) => Some(err),
+            Error::ReadString(ref err) => Some(err),
+        }
+    }
+
+    fn description(&self) -> &str {
+        match *self {
+            Error::CreatePasteboard(ref _err) => "Failed to create pasteboard",
+            Error::ReadString(ref _err) => "Failed to read string from pasteboard",
+        }
+    }
+}
+
+impl ::std::fmt::Display for Error {
+    fn fmt(&self, f: &mut ::std::fmt::Formatter) -> ::std::fmt::Result {
+        match *self {
+            Error::CreatePasteboard(ref err) => {
+                write!(f, "Failed to create pasteboard: {}", err)
+            },
+            Error::ReadString(ref err) => {
+                write!(f, "Failed to read string from pasteboard: {}", err)
+            },
+        }
+    }
+}
+
+impl From<ns::NewPasteboardError> for Error {
+    fn from(val: ns::NewPasteboardError) -> Error {
+        Error::CreatePasteboard(val)
+    }
+}
+
+impl From<ns::ReadStringError> for Error {
+    fn from(val: ns::ReadStringError) -> Error {
+        Error::ReadString(val)
+    }
+}
+
+pub struct Clipboard(ns::Pasteboard);
+
+impl super::Load for Clipboard {
+    type Err = Error;
 
     fn new() -> Result<Self, Error> {
-        Ok(Clipboard)
+        Ok(Clipboard(try!(ns::Pasteboard::new())))
     }
 
     fn load_primary(&self) -> Result<String, Self::Err> {
-        Ok(String::new())
+        Ok(try!(self::ns::PasteboardReadObject::<String>::read_object(&self.0)))
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::Clipboard;
+    use ::Load;
+
+    #[test]
+    fn create_clipboard_and_load_contents() {
+        let clipboard = Clipboard::new().unwrap();
+        println!("{:?}", clipboard.load_primary());
     }
 }