Add top-level docs and update README

[netwatcher] / src / lib.rs

diff --git a/src/lib.rs b/src/lib.rs
index 36cbddc7d5037a74bc13d654c7dea42f40aea2cb..dfc4395cfda75ad9bf7a81f33d887edc96c4a390 100644 (file)
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -1,20 +1,70 @@
+//! # netwatcher
+//!
+//! `netwatcher` is a cross-platform library for enumerating network interfaces and their
+//! IP addresses, featuring the ability to watch for changes to those interfaces
+//! _efficiently_. It uses platform-specific methods to detect when interface changes
+//! have occurred instead of polling, which means that you find out about changes more
+//! quickly and there is no CPU or wakeup overhead when nothing is happening.
+//! 
+//! ## List example
+//! 
+//! ```
+//! /// Returns a HashMap from ifindex (a `u32`) to an `Interface` struct
+//! let interfaces = netwatcher::list_interfaces().unwrap();
+//! for i in interfaces.values() {
+//!     println!("interface {} has {} IPs", i.name, i.ips.len());
+//! }
+//! ```
+//! 
+//! ## Watch example
+//! 
+//! ```
+//! let handle = netwatcher::watch_interfaces(|update| {
+//!     // This callback will fire once immediately with the existing state
+//! 
+//!     // Update includes the latest snapshot of all interfaces
+//!     println!("Current interface map: {:#?}", update.interfaces);
+//! 
+//!     // The `UpdateDiff` describes changes since previous callback
+//!     // You can choose whether to use the snapshot, diff, or both
+//!     println!("ifindexes added: {:?}", update.diff.added);
+//!     println!("ifindexes removed: {:?}", update.diff.removed);
+//!     for (ifindex, if_diff) in update.diff.modified {
+//!         println!("Interface index {} has changed", ifindex);
+//!         println!("Added IPs: {:?}", if_diff.addrs_added);
+//!         println!("Removed IPs: {:?}", if_diff.addrs_removed);
+//!     }
+//! });
+//! // keep `handle` alive as long as you want callbacks
+//! // ...
+//! drop(handle);
+//! ```
+

 use std::{
     collections::{HashMap, HashSet},
     net::{IpAddr, Ipv4Addr, Ipv6Addr},
     ops::Sub,
 };
 
 use std::{
     collections::{HashMap, HashSet},
     net::{IpAddr, Ipv4Addr, Ipv6Addr},
     ops::Sub,
 };
 

+mod error;
+

 #[cfg_attr(windows, path = "list_win.rs")]
 #[cfg_attr(unix, path = "list_unix.rs")]
 mod list;
 
 #[cfg_attr(windows, path = "watch_win.rs")]
 #[cfg_attr(target_vendor = "apple", path = "watch_mac.rs")]
 #[cfg_attr(windows, path = "list_win.rs")]
 #[cfg_attr(unix, path = "list_unix.rs")]
 mod list;
 
 #[cfg_attr(windows, path = "watch_win.rs")]
 #[cfg_attr(target_vendor = "apple", path = "watch_mac.rs")]

-#[cfg_attr(target_os = "linux", path = "watch_linux.rs")]
+#[cfg_attr(
+    any(target_os = "linux", target_os = "android"),
+    path = "watch_linux.rs"
+)]

 mod watch;
 
 type IfIndex = u32;
 
 mod watch;
 
 type IfIndex = u32;
 

+pub use error::Error;
+
+/// Information about one network interface at a point in time.

 #[derive(Debug, Clone, PartialEq, Eq)]
 pub struct Interface {
     pub index: u32,
 #[derive(Debug, Clone, PartialEq, Eq)]
 pub struct Interface {
     pub index: u32,


@@ -24,6 +74,7 @@ pub struct Interface {
 }
 
 impl Interface {
 }
 
 impl Interface {

+    /// Helper to iterate over only the IPv4 addresses on this interface.

     pub fn ipv4_ips(&self) -> impl Iterator<Item = &Ipv4Addr> {
         self.ips.iter().filter_map(|ip| match ip {
             IpAddr::V4(v4) => Some(v4),
     pub fn ipv4_ips(&self) -> impl Iterator<Item = &Ipv4Addr> {
         self.ips.iter().filter_map(|ip| match ip {
             IpAddr::V4(v4) => Some(v4),


@@ -31,6 +82,7 @@ impl Interface {
         })
     }
 
         })
     }
 

+    /// Helper to iterate over only the IPv6 addresses on this interface.

     pub fn ipv6_ips(&self) -> impl Iterator<Item = &Ipv6Addr> {
         self.ips.iter().filter_map(|ip| match ip {
             IpAddr::V4(_) => None,
     pub fn ipv6_ips(&self) -> impl Iterator<Item = &Ipv6Addr> {
         self.ips.iter().filter_map(|ip| match ip {
             IpAddr::V4(_) => None,


@@ -39,12 +91,17 @@ impl Interface {
     }
 }
 
     }
 }
 

+/// Information delivered via callback when a network interface change is detected.
+///
+/// This contains up-to-date information about all interfaces, plus a diff which
+/// details which interfaces and IP addresses have changed since the last callback.

 #[derive(Debug, Clone, PartialEq, Eq)]
 pub struct Update {
     pub interfaces: HashMap<IfIndex, Interface>,
     pub diff: UpdateDiff,
 }
 
 #[derive(Debug, Clone, PartialEq, Eq)]
 pub struct Update {
     pub interfaces: HashMap<IfIndex, Interface>,
     pub diff: UpdateDiff,
 }
 

+/// What changed between one `Update` and the next.

 #[derive(Debug, Clone, PartialEq, Eq, Default)]
 pub struct UpdateDiff {
     pub added: Vec<IfIndex>,
 #[derive(Debug, Clone, PartialEq, Eq, Default)]
 pub struct UpdateDiff {
     pub added: Vec<IfIndex>,


@@ -52,6 +109,7 @@ pub struct UpdateDiff {
     pub modified: HashMap<IfIndex, InterfaceDiff>,
 }
 
     pub modified: HashMap<IfIndex, InterfaceDiff>,
 }
 

+/// What changed within a single interface between updates, if it was present in both.

 #[derive(Debug, Clone, PartialEq, Eq, Default)]
 pub struct InterfaceDiff {
     pub hw_addr_changed: bool,
 #[derive(Debug, Clone, PartialEq, Eq, Default)]
 pub struct InterfaceDiff {
     pub hw_addr_changed: bool,


@@ -59,12 +117,6 @@ pub struct InterfaceDiff {
     pub addrs_removed: Vec<IpAddr>,
 }
 
     pub addrs_removed: Vec<IpAddr>,
 }
 

-#[derive(Debug, Clone, PartialEq, Eq)]
-pub enum Error {
-    // TODO: handle all cases with proper sources
-    Internal,
-}
-

 #[derive(Default, PartialEq, Eq)]
 struct List(HashMap<IfIndex, Interface>);
 
 #[derive(Default, PartialEq, Eq)]
 struct List(HashMap<IfIndex, Interface>);
 


@@ -111,14 +163,39 @@ impl List {
     }
 }
 
     }
 }
 

+/// A handle to keep alive as long as you wish to receive callbacks.
+///
+/// If the callback is executing at the time the handle is dropped, drop will block until
+/// the callback is finished and it's guaranteed that it will not be called again.
+///
+/// Do not drop the handle from within the callback itself. It will probably deadlock.

 pub struct WatchHandle {
     _inner: watch::WatchHandle,
 }
 
 pub struct WatchHandle {
     _inner: watch::WatchHandle,
 }
 

+/// Retrieve information about all enabled network interfaces and their IP addresses.
+///
+/// This is a once-off operation. If you want to detect changes over time, see `watch_interfaces`.

 pub fn list_interfaces() -> Result<HashMap<IfIndex, Interface>, Error> {
     list::list_interfaces().map(|list| list.0)
 }
 
 pub fn list_interfaces() -> Result<HashMap<IfIndex, Interface>, Error> {
     list::list_interfaces().map(|list| list.0)
 }
 

-pub fn watch_interfaces<F: FnMut(Update) + 'static>(callback: F) -> Result<WatchHandle, Error> {
+/// Retrieve interface information and watch for changes, which will be delivered via callback.
+///
+/// If setting up the watch is successful, this returns a `WatchHandle` which must be kept for
+/// as long as the provided callback should operate.
+///
+/// The callback will fire once immediately with an initial interface list, and a diff as if
+/// there were originally no interfaces present.
+///
+/// This function will return an error if there is a problem configuring the watcher, or if there
+/// is an error retrieving the initial interface list.
+///
+/// We assume that if listing the interfaces worked the first time, then it will continue to work
+/// for as long as the watcher is running. If listing interfaces begins to fail later, those
+/// failures will be swallowed and the callback will not be called for that change event.
+pub fn watch_interfaces<F: FnMut(Update) + Send + 'static>(
+    callback: F,
+) -> Result<WatchHandle, Error> {

     watch::watch_interfaces(callback).map(|handle| WatchHandle { _inner: handle })
 }
     watch::watch_interfaces(callback).map(|handle| WatchHandle { _inner: handle })
 }