Utilize cfg_attr instead of a build script.

This also updates serde to a more recent version (1.0).

Author: Mark-Simulacrum

Cargo.toml

@@ -11,15 +11,14 @@ documentation = "http://alexcrichton.com/backtrace-rs"
 description = """
 A library to acquire a stack trace (backtrace) at runtime in a Rust program.
 """
-build = "build.rs"
-
 [dependencies]
 libc = "0.2"
 cfg-if = "0.1"
 rustc-demangle = "0.1.4"
 
 # Optionally enable the ability to serialize a `Backtrace`
-serde = { version = "0.8", optional = true }
+serde = { version = "1.0", optional = true }
+serde_derive = { version = "1.0", optional = true }
 rustc-serialize = { version = "0.3", optional = true }
 
 # Optionally demangle C++ frames' symbols in backtraces.
@@ -33,9 +32,6 @@ winapi = { version = "0.2.5", optional = true }
 [target.'cfg(all(unix, not(target_os = "emscripten"), not(target_os = "macos"), not(target_os = "ios")))'.dependencies]
 backtrace-sys = { path = "backtrace-sys", version = "0.1.3", optional = true }
 
-[build-dependencies]
-serde_codegen = { version = "0.8", optional = true }
-
 # Each feature controls the two phases of finding a backtrace: getting a
 # backtrace and then resolving instruction pointers to symbols. The default
 # feature enables all the necessary features for each platform this library
@@ -88,4 +84,4 @@ default = ["libunwind", "libbacktrace", "coresymbolication", "dladdr", "dbghelp"
     #
     # Various features used for enabling rustc-serialize or syntex codegen.
     serialize-rustc = ["rustc-serialize"]
-    serialize-serde = ["serde", "serde_codegen"]
+    serialize-serde = ["serde", "serde_derive"]

build.rs

@@ -5,28 +5,13 @@ use std::path::{Path, PathBuf};
 
 use {trace, resolve, SymbolName};
 
-// Ok so the `//~ HACK` directives here are, well, hacks. Right now we want to
-// compile on stable for serde support, but we also want to use
-// #[derive(Serialize, Deserialize)] macros *along* with the
-// `#[derive(RustcEncodable, RustcDecodable)]` macros. In theory both of these
-// can be behind a #[cfg_attr], but that unfortunately doesn't work for two
-// reasons:
-//
-// 1. rust-lang/rust#32957 - means the include! of this module doesn't expand
-//    the RustcDecodable/RustcEncodable blocks.
-// 2. serde-rs/serde#148 - means that Serialize/Deserialize won't get expanded.
-//
-// We just hack around it by doing #[cfg_attr] manually essentially. Our build
-// script will just strip the `//~ HACKn` prefixes here if the corresponding
-// feature is enabled.
-
 /// Representation of an owned and self-contained backtrace.
 ///
 /// This structure can be used to capture a backtrace at various points in a
 /// program and later used to inspect what the backtrace was at that time.
 #[derive(Clone)]
-//~ HACK1 #[derive(RustcDecodable, RustcEncodable)]
-//~ HACK2 #[derive(Deserialize, Serialize)]
+#[cfg_attr(feature = "serialize-rustc", derive(RustcDecodable, RustcEncodable))]
+#[cfg_attr(feature = "serialize-serde", derive(Deserialize, Serialize))]
 pub struct Backtrace {
     frames: Vec<BacktraceFrame>,
 }
@@ -36,8 +21,8 @@ pub struct Backtrace {
 /// This type is returned as a list from `Backtrace::frames` and represents one
 /// stack frame in a captured backtrace.
 #[derive(Clone)]
-//~ HACK1 #[derive(RustcDecodable, RustcEncodable)]
-//~ HACK2 #[derive(Deserialize, Serialize)]
+#[cfg_attr(feature = "serialize-rustc", derive(RustcDecodable, RustcEncodable))]
+#[cfg_attr(feature = "serialize-serde", derive(Deserialize, Serialize))]
 pub struct BacktraceFrame {
     ip: usize,
     symbol_address: usize,
@@ -49,8 +34,8 @@ pub struct BacktraceFrame {
 /// This type is returned as a list from `BacktraceFrame::symbols` and
 /// represents the metadata for a symbol in a backtrace.
 #[derive(Clone)]
-//~ HACK1 #[derive(RustcDecodable, RustcEncodable)]
-//~ HACK2 #[derive(Deserialize, Serialize)]
+#[cfg_attr(feature = "serialize-rustc", derive(RustcDecodable, RustcEncodable))]
+#[cfg_attr(feature = "serialize-serde", derive(Deserialize, Serialize))]
 pub struct BacktraceSymbol {
     name: Option<Vec<u8>>,
     addr: Option<usize>,

src/capture.rs

@@ -77,6 +77,10 @@ extern crate libc;
 #[cfg(feature = "serde")]
 extern crate serde;
 
+#[cfg(feature = "serde_derive")]
+#[cfg_attr(feature = "serde_derive", macro_use)]
+extern crate serde_derive;
+
 #[cfg(feature = "rustc-serialize")]
 extern crate rustc_serialize;
 
@@ -100,9 +104,7 @@ pub use symbolize::{resolve, Symbol, SymbolName};
 mod symbolize;
 
 pub use capture::{Backtrace, BacktraceFrame, BacktraceSymbol};
-mod capture {
-    include!(concat!(env!("OUT_DIR"), "/capture.rs"));
-}
+mod capture;
 
 #[allow(dead_code)]
 struct Bomb {

src/lib.rs

@@ -160,7 +160,7 @@ fn is_serde() {
     extern crate serde;
 
     fn is_serialize<T: serde::ser::Serialize>() {}
-    fn is_deserialize<T: serde::de::Deserialize>() {}
+    fn is_deserialize<T: serde::de::DeserializeOwned>() {}
 
     is_serialize::<backtrace::Backtrace>();
     is_deserialize::<backtrace::Backtrace>();