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//! Types and traits for easily getting a message's arguments, or appening a message with arguments. //! //! Also see the arguments guide (in the examples directory). //! //! A message has `read1`, `read2` etc, and `append1`, `append2` etc, which is your //! starting point into this module's types. //! //! **Append a**: //! //! `bool, u8, u16, u32, u64, i16, i32, i64, f64` - the corresponding D-Bus basic type //! //! `&str` - a D-Bus string. D-Bus strings do not allow null characters, so //! if the string contains null characters, it will be cropped //! to only include the data before the null character. (Tip: This allows for skipping an //! allocation by writing a string literal which ends with a null character.) //! //! `&[T] where T: Append` - a D-Bus array. Note: can use an efficient fast-path in case of //! T being an FixedArray type. //! //! `Array<T, I> where T: Append, I: Iterator<Item=T>` - a D-Bus array, maximum flexibility. //! //! `Variant<T> where T: Append` - a D-Bus variant. //! //! `(T1, T2) where T1: Append, T2: Append` - tuples are D-Bus structs. Implemented up to 12. //! //! `Dict<K, V, I> where K: Append + DictKey, V: Append, I: Iterator<Item=(&K, &V)>` - A D-Bus dict (array of dict entries). //! //! `Path` - a D-Bus object path. //! //! `Signature` - a D-Bus signature. //! //! `OwnedFd` - shares the file descriptor with the remote side. //! //! **Get / read a**: //! //! `bool, u8, u16, u32, u64, i16, i32, i64, f64` - the corresponding D-Bus basic type //! //! `&str`, `&CStr` - a D-Bus string. D-Bus strings are always UTF-8 and do not contain null characters. //! //! `&[T] where T: FixedArray` - a D-Bus array of integers or f64. //! //! `Array<T, Iter> where T: Get` - a D-Bus array, maximum flexibility. Implements Iterator so you can easily //! collect it into, e g, a `Vec`. //! //! `Variant<T> where T: Get` - a D-Bus variant. Use this type of Variant if you know the inner type. //! //! `Variant<Iter>` - a D-Bus variant. This type of Variant allows you to examine the inner type. //! //! `(T1, T2) where T1: Get, T2: Get` - tuples are D-Bus structs. Implemented up to 12. //! //! `Dict<K, V, Iter> where K: Get + DictKey, V: Get` - A D-Bus dict (array of dict entries). Implements Iterator so you can easily //! collect it into, e g, a `HashMap`. //! //! `Path` - a D-Bus object path. //! //! `Signature` - a D-Bus signature. //! //! `OwnedFd` - a file descriptor sent from the remote side. //! mod msgarg; mod basic_impl; mod variantstruct_impl; mod array_impl; pub use self::msgarg::{Arg, FixedArray, Get, DictKey, Append, RefArg, AppendAll, ReadAll, cast, cast_mut}; pub use self::array_impl::{Array, Dict}; pub use self::variantstruct_impl::Variant; use std::{fmt, mem, ptr, error}; use {ffi, Message, Signature, Path, OwnedFd}; use std::ffi::{CStr, CString}; use std::os::raw::{c_void, c_int}; fn check(f: &str, i: u32) { if i == 0 { panic!("D-Bus error: '{}' failed", f) }} fn ffi_iter() -> ffi::DBusMessageIter { unsafe { mem::zeroed() }} #[derive(Clone, Copy)] /// Helper struct for appending one or more arguments to a Message. pub struct IterAppend<'a>(ffi::DBusMessageIter, &'a Message); impl<'a> IterAppend<'a> { /// Creates a new IterAppend struct. pub fn new(m: &'a mut Message) -> IterAppend<'a> { let mut i = ffi_iter(); unsafe { ffi::dbus_message_iter_init_append(m.ptr(), &mut i) }; IterAppend(i, m) } /// Appends the argument. pub fn append<T: Append>(&mut self, a: T) { a.append(self) } fn append_container<F: FnOnce(&mut IterAppend<'a>)>(&mut self, arg_type: ArgType, sig: Option<&CStr>, f: F) { let mut s = IterAppend(ffi_iter(), self.1); let p = sig.map(|s| s.as_ptr()).unwrap_or(ptr::null()); check("dbus_message_iter_open_container", unsafe { ffi::dbus_message_iter_open_container(&mut self.0, arg_type as c_int, p, &mut s.0) }); f(&mut s); check("dbus_message_iter_close_container", unsafe { ffi::dbus_message_iter_close_container(&mut self.0, &mut s.0) }); } /// Low-level function to append a variant. /// /// Use in case the `Variant` struct is not flexible enough - /// the easier way is to just call e g "append1" on a message and supply a `Variant` parameter. /// /// In order not to get D-Bus errors: during the call to "f" you need to call "append" on /// the supplied `IterAppend` exactly once, /// and with a value which has the same signature as inner_sig. pub fn append_variant<F: FnOnce(&mut IterAppend<'a>)>(&mut self, inner_sig: &Signature, f: F) { self.append_container(ArgType::Variant, Some(inner_sig.as_cstr()), f) } /// Low-level function to append an array. /// /// Use in case the `Array` struct is not flexible enough - /// the easier way is to just call e g "append1" on a message and supply an `Array` parameter. /// /// In order not to get D-Bus errors: during the call to "f", you should only call "append" on /// the supplied `IterAppend` with values which has the same signature as inner_sig. pub fn append_array<F: FnOnce(&mut IterAppend<'a>)>(&mut self, inner_sig: &Signature, f: F) { self.append_container(ArgType::Array, Some(inner_sig.as_cstr()), f) } /// Low-level function to append a struct. /// /// Use in case tuples are not flexible enough - /// the easier way is to just call e g "append1" on a message and supply a tuple parameter. pub fn append_struct<F: FnOnce(&mut IterAppend<'a>)>(&mut self, f: F) { self.append_container(ArgType::Struct, None, f) } /// Low-level function to append a dict entry. /// /// Use in case the `Dict` struct is not flexible enough - /// the easier way is to just call e g "append1" on a message and supply a `Dict` parameter. /// /// In order not to get D-Bus errors: during the call to "f", you should call "append" once /// for the key, then once for the value. You should only call this function for a subiterator /// you got from calling "append_dict", and signatures need to match what you specified in "append_dict". pub fn append_dict_entry<F: FnOnce(&mut IterAppend<'a>)>(&mut self, f: F) { self.append_container(ArgType::DictEntry, None, f) } /// Low-level function to append a dict. /// /// Use in case the `Dict` struct is not flexible enough - /// the easier way is to just call e g "append1" on a message and supply a `Dict` parameter. /// /// In order not to get D-Bus errors: during the call to "f", you should only call "append_dict_entry" /// for the subiterator - do this as many times as the number of dict entries. pub fn append_dict<F: FnOnce(&mut IterAppend<'a>)>(&mut self, key_sig: &Signature, value_sig: &Signature, f: F) { let sig = format!("{{{}{}}}", key_sig, value_sig); self.append_container(Array::<bool,()>::ARG_TYPE, Some(&CString::new(sig).unwrap()), f); } } #[derive(Clone, Copy)] /// Helper struct for retrieve one or more arguments from a Message. pub struct Iter<'a>(ffi::DBusMessageIter, &'a Message, u32); impl<'a> Iter<'a> { /// Creates a new struct for iterating over the arguments of a message, starting with the first argument. pub fn new(m: &'a Message) -> Iter<'a> { let mut i = ffi_iter(); unsafe { ffi::dbus_message_iter_init(m.ptr(), &mut i) }; Iter(i, m, 0) } /// Returns the current argument, if T is the argument type. Otherwise returns None. pub fn get<T: Get<'a>>(&mut self) -> Option<T> { T::get(self) } /// Returns the current argument as a trait object (experimental). /// /// Note: For the more complex arguments (arrays / dicts / structs, and especially /// combinations thereof), their internal representations are still a bit in flux. /// Instead, use as_iter() to read the values of those. /// /// The rest are unlikely to change - Variants are `Variant<Box<RefArg>>`, strings are `String`, /// paths are `Path<'static>`, signatures are `Signature<'static>`, Int32 are `i32s` and so on. pub fn get_refarg(&mut self) -> Option<Box<RefArg + 'static>> { Some(match self.arg_type() { ArgType::Array => array_impl::get_array_refarg(self), ArgType::Variant => Box::new(Variant::new_refarg(self).unwrap()), ArgType::Boolean => Box::new(self.get::<bool>().unwrap()), ArgType::Invalid => return None, ArgType::String => Box::new(self.get::<String>().unwrap()), ArgType::DictEntry => unimplemented!(), ArgType::Byte => Box::new(self.get::<u8>().unwrap()), ArgType::Int16 => Box::new(self.get::<i16>().unwrap()), ArgType::UInt16 => Box::new(self.get::<u16>().unwrap()), ArgType::Int32 => Box::new(self.get::<i32>().unwrap()), ArgType::UInt32 => Box::new(self.get::<u32>().unwrap()), ArgType::Int64 => Box::new(self.get::<i64>().unwrap()), ArgType::UInt64 => Box::new(self.get::<u64>().unwrap()), ArgType::Double => Box::new(self.get::<f64>().unwrap()), ArgType::UnixFd => Box::new(self.get::<OwnedFd>().unwrap()), ArgType::Struct => Box::new(self.recurse(ArgType::Struct).unwrap().collect::<Vec<_>>()), ArgType::ObjectPath => Box::new(self.get::<Path>().unwrap().into_static()), ArgType::Signature => Box::new(self.get::<Signature>().unwrap().into_static()), }) } /// Returns the type signature for the current argument. pub fn signature(&mut self) -> Signature<'static> { unsafe { let c = ffi::dbus_message_iter_get_signature(&mut self.0); assert!(c != ptr::null_mut()); let cc = CStr::from_ptr(c); let r = Signature::new(cc.to_bytes()); ffi::dbus_free(c as *mut c_void); r.unwrap() } } /// The raw arg_type for the current item. /// /// Unlike Arg::arg_type, this requires access to self and is not a static method. /// You can match this against Arg::arg_type for different types to understand what type the current item is. /// In case you're past the last argument, this function will return 0. pub fn arg_type(&mut self) -> ArgType { let s = unsafe { ffi::dbus_message_iter_get_arg_type(&mut self.0) }; ArgType::from_i32(s as i32).unwrap() } /// Returns false if there are no more items. pub fn next(&mut self) -> bool { self.2 += 1; unsafe { ffi::dbus_message_iter_next(&mut self.0) != 0 } } /// Wrapper around `get` and `next`. Calls `get`, and then `next` if `get` succeeded. /// /// Also returns a `Result` rather than an `Option` to give an error if successful. /// /// # Example /// ```ignore /// struct ServiceBrowserItemNew { /// interface: i32, /// protocol: i32, /// name: String, /// item_type: String, /// domain: String, /// flags: u32, /// } /// /// fn service_browser_item_new_msg(m: &Message) -> Result<ServiceBrowserItemNew, TypeMismatchError> { /// let mut iter = m.iter_init(); /// Ok(ServiceBrowserItemNew { /// interface: iter.read()?, /// protocol: iter.read()?, /// name: iter.read()?, /// item_type: iter.read()?, /// domain: iter.read()?, /// flags: iter.read()?, /// }) /// } /// ``` pub fn read<T: Arg + Get<'a>>(&mut self) -> Result<T, TypeMismatchError> { let r = try!(self.get().ok_or_else(|| TypeMismatchError { expected: T::ARG_TYPE, found: self.arg_type(), position: self.2 })); self.next(); Ok(r) } /// If the current argument is a container of the specified arg_type, then a new /// Iter is returned which is for iterating over the contents inside the container. /// /// Primarily for internal use (the "get" function is more ergonomic), but could be /// useful for recursing into containers with unknown types. pub fn recurse(&mut self, arg_type: ArgType) -> Option<Iter<'a>> { let containers = [ArgType::Array, ArgType::DictEntry, ArgType::Struct, ArgType::Variant]; if !containers.iter().any(|&t| t == arg_type) { return None; } let mut subiter = ffi_iter(); unsafe { if ffi::dbus_message_iter_get_arg_type(&mut self.0) != arg_type as c_int { return None }; ffi::dbus_message_iter_recurse(&mut self.0, &mut subiter) } Some(Iter(subiter, self.1, 0)) } } impl<'a> fmt::Debug for Iter<'a> { fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result { let mut z = self.clone(); let mut t = f.debug_tuple("Iter"); loop { t.field(&z.arg_type()); if !z.next() { break } } t.finish() } } impl<'a> Iterator for Iter<'a> { type Item = Box<RefArg + 'static>; fn next(&mut self) -> Option<Self::Item> { let r = self.get_refarg(); if r.is_some() { self.next(); } r } } /// Type of Argument /// /// use this to figure out, e g, which type of argument is at the current position of Iter. #[repr(u8)] #[derive(Copy, Clone, Debug, Hash, Eq, PartialEq, Ord, PartialOrd)] pub enum ArgType { /// Dicts are Arrays of dict entries, so Dict types will have Array as ArgType. Array = ffi::DBUS_TYPE_ARRAY as u8, /// Variant Variant = ffi::DBUS_TYPE_VARIANT as u8, /// bool Boolean = ffi::DBUS_TYPE_BOOLEAN as u8, /// Invalid arg type - this is also the ArgType returned when there are no more arguments available. Invalid = ffi::DBUS_TYPE_INVALID as u8, /// String String = ffi::DBUS_TYPE_STRING as u8, /// Dict entry; you'll usually not encounter this one as dicts are arrays of dict entries. DictEntry = ffi::DBUS_TYPE_DICT_ENTRY as u8, /// u8 Byte = ffi::DBUS_TYPE_BYTE as u8, /// i16 Int16 = ffi::DBUS_TYPE_INT16 as u8, /// u16 UInt16 = ffi::DBUS_TYPE_UINT16 as u8, /// i32 Int32 = ffi::DBUS_TYPE_INT32 as u8, /// u32 UInt32 = ffi::DBUS_TYPE_UINT32 as u8, /// i64 Int64 = ffi::DBUS_TYPE_INT64 as u8, /// u64 UInt64 = ffi::DBUS_TYPE_UINT64 as u8, /// f64 Double = ffi::DBUS_TYPE_DOUBLE as u8, /// OwnedFd UnixFd = ffi::DBUS_TYPE_UNIX_FD as u8, /// Use tuples or Vec<Box<RefArg>> to read/write structs. Struct = ffi::DBUS_TYPE_STRUCT as u8, /// Path ObjectPath = ffi::DBUS_TYPE_OBJECT_PATH as u8, /// Signature Signature = ffi::DBUS_TYPE_SIGNATURE as u8, } const ALL_ARG_TYPES: [(ArgType, &'static str); 18] = [(ArgType::Variant, "Variant"), (ArgType::Array, "Array/Dict"), (ArgType::Struct, "Struct"), (ArgType::String, "String"), (ArgType::DictEntry, "Dict entry"), (ArgType::ObjectPath, "Path"), (ArgType::Signature, "Signature"), (ArgType::UnixFd, "OwnedFd"), (ArgType::Boolean, "bool"), (ArgType::Byte, "u8"), (ArgType::Int16, "i16"), (ArgType::Int32, "i32"), (ArgType::Int64, "i64"), (ArgType::UInt16, "u16"), (ArgType::UInt32, "u32"), (ArgType::UInt64, "u64"), (ArgType::Double, "f64"), (ArgType::Invalid, "nothing")]; impl ArgType { /// A str corresponding to the name of a Rust type. pub fn as_str(self) -> &'static str { ALL_ARG_TYPES.iter().skip_while(|a| a.0 != self).next().unwrap().1 } /// Converts an i32 to an ArgType (or an error). pub fn from_i32(i: i32) -> Result<ArgType, String> { for &(a, _) in &ALL_ARG_TYPES { if a as i32 == i { return Ok(a); } } Err(format!("Invalid ArgType {} ({})", i, i as u8 as char)) } } /// Error struct to indicate a D-Bus argument type mismatch. /// /// Might be returned from `iter::read()`. #[derive(Clone, Copy, Debug, PartialEq, Eq)] pub struct TypeMismatchError { expected: ArgType, found: ArgType, position: u32, } impl TypeMismatchError { /// The ArgType we were trying to read, but failed pub fn expected_arg_type(&self) -> ArgType { self.expected } /// The ArgType we should have been trying to read, if we wanted the read to succeed pub fn found_arg_type(&self) -> ArgType { self.found } /// At what argument was the error found? /// /// Returns 0 for first argument, 1 for second argument, etc. pub fn pos(&self) -> u32 { self.position } } impl error::Error for TypeMismatchError { fn description(&self) -> &str { "D-Bus argument type mismatch" } fn cause(&self) -> Option<&error::Error> { None } } impl fmt::Display for TypeMismatchError { fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result { write!(f, "{} at position {}: expected {}, found {}", (self as &error::Error).description(), self.position, self.expected.as_str(), if self.expected == self.found { "same but still different somehow" } else { self.found.as_str() } ) } } #[allow(dead_code)] fn test_compile() { let mut q = IterAppend::new(unsafe { mem::transmute(0usize) }); q.append(5u8); q.append(Array::new(&[5u8, 6, 7])); q.append((8u8, &[9u8, 6, 7][..])); q.append(Variant((6u8, 7u8))); }