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</pre><pre class="rust ">
<span class="doccomment">//! A library for acquiring a backtrace at runtime</span>
<span class="doccomment">//!</span>
<span class="doccomment">//! This library is meant to supplement the `RUST_BACKTRACE=1` support of the</span>
<span class="doccomment">//! standard library by allowing an acquisition of a backtrace at runtime</span>
<span class="doccomment">//! programmatically. The backtraces generated by this library do not need to be</span>
<span class="doccomment">//! parsed, for example, and expose the functionality of multiple backend</span>
<span class="doccomment">//! implementations.</span>
<span class="doccomment">//!</span>
<span class="doccomment">//! # Implementation</span>
<span class="doccomment">//!</span>
<span class="doccomment">//! This library makes use of a number of strategies for actually acquiring a</span>
<span class="doccomment">//! backtrace. For example unix uses libgcc's libunwind bindings by default to</span>
<span class="doccomment">//! acquire a backtrace, but coresymbolication or dladdr is used on OSX to</span>
<span class="doccomment">//! acquire symbol names while linux uses gcc's libbacktrace.</span>
<span class="doccomment">//!</span>
<span class="doccomment">//! When using the default feature set of this library the "most reasonable" set</span>
<span class="doccomment">//! of defaults is chosen for the current platform, but the features activated</span>
<span class="doccomment">//! can also be controlled at a finer granularity.</span>
<span class="doccomment">//!</span>
<span class="doccomment">//! # Platform Support</span>
<span class="doccomment">//!</span>
<span class="doccomment">//! Currently this library is verified to work on Linux, OSX, and Windows, but</span>
<span class="doccomment">//! it may work on other platforms as well. Note that the quality of the</span>
<span class="doccomment">//! backtrace may vary across platforms.</span>
<span class="doccomment">//!</span>
<span class="doccomment">//! # API Principles</span>
<span class="doccomment">//!</span>
<span class="doccomment">//! This library attempts to be as flexible as possible to accommodate different</span>
<span class="doccomment">//! backend implementations of acquiring a backtrace. Consequently the currently</span>
<span class="doccomment">//! exported functions are closure-based as opposed to the likely expected</span>
<span class="doccomment">//! iterator-based versions. This is done due to limitations of the underlying</span>
<span class="doccomment">//! APIs used from the system.</span>
<span class="doccomment">//!</span>
<span class="doccomment">//! # Usage</span>
<span class="doccomment">//!</span>
<span class="doccomment">//! First, add this to your Cargo.toml</span>
<span class="doccomment">//!</span>
<span class="doccomment">//! ```toml</span>
<span class="doccomment">//! [dependencies]</span>
<span class="doccomment">//! backtrace = "0.2"</span>
<span class="doccomment">//! ```</span>
<span class="doccomment">//!</span>
<span class="doccomment">//! Next:</span>
<span class="doccomment">//!</span>
<span class="doccomment">//! ```</span>
<span class="doccomment">//! extern crate backtrace;</span>
<span class="doccomment">//!</span>
<span class="doccomment">//! fn main() {</span>
<span class="doccomment">//! backtrace::trace(|frame| {</span>
<span class="doccomment">//! let ip = frame.ip();</span>
<span class="doccomment">//! let symbol_address = frame.symbol_address();</span>
<span class="doccomment">//!</span>
<span class="doccomment">//! // Resolve this instruction pointer to a symbol name</span>
<span class="doccomment">//! backtrace::resolve(ip, |symbol| {</span>
<span class="doccomment">//! if let Some(name) = symbol.name() {</span>
<span class="doccomment">//! // ...</span>
<span class="doccomment">//! }</span>
<span class="doccomment">//! if let Some(filename) = symbol.filename() {</span>
<span class="doccomment">//! // ...</span>
<span class="doccomment">//! }</span>
<span class="doccomment">//! });</span>
<span class="doccomment">//!</span>
<span class="doccomment">//! true // keep going to the next frame</span>
<span class="doccomment">//! });</span>
<span class="doccomment">//! }</span>
<span class="doccomment">//! ```</span>
<span class="attribute">#![<span class="ident">doc</span>(<span class="ident">html_root_url</span> <span class="op">=</span> <span class="string">"http://alexcrichton.com/backtrace-rs"</span>)]</span>
<span class="attribute">#![<span class="ident">deny</span>(<span class="ident">missing_docs</span>)]</span>
<span class="attribute">#![<span class="ident">deny</span>(<span class="ident">warnings</span>)]</span>
<span class="attribute">#[<span class="ident">cfg</span>(<span class="ident">unix</span>)]</span>
<span class="kw">extern</span> <span class="kw">crate</span> <span class="ident">libc</span>;
<span class="attribute">#[<span class="ident">cfg</span>(<span class="ident">all</span>(<span class="ident">windows</span>, <span class="ident">feature</span> <span class="op">=</span> <span class="string">"winapi"</span>))]</span> <span class="kw">extern</span> <span class="kw">crate</span> <span class="ident">winapi</span>;
<span class="attribute">#[<span class="ident">cfg</span>(<span class="ident">feature</span> <span class="op">=</span> <span class="string">"serde_derive"</span>)]</span>
<span class="attribute">#[<span class="ident">cfg_attr</span>(<span class="ident">feature</span> <span class="op">=</span> <span class="string">"serde_derive"</span>, <span class="ident">macro_use</span>)]</span>
<span class="kw">extern</span> <span class="kw">crate</span> <span class="ident">serde_derive</span>;
<span class="attribute">#[<span class="ident">cfg</span>(<span class="ident">feature</span> <span class="op">=</span> <span class="string">"rustc-serialize"</span>)]</span>
<span class="kw">extern</span> <span class="kw">crate</span> <span class="ident">rustc_serialize</span>;
<span class="attribute">#[<span class="ident">macro_use</span>]</span>
<span class="kw">extern</span> <span class="kw">crate</span> <span class="ident">cfg_if</span>;
<span class="kw">extern</span> <span class="kw">crate</span> <span class="ident">rustc_demangle</span>;
<span class="attribute">#[<span class="ident">cfg</span>(<span class="ident">feature</span> <span class="op">=</span> <span class="string">"cpp_demangle"</span>)]</span>
<span class="kw">extern</span> <span class="kw">crate</span> <span class="ident">cpp_demangle</span>;
<span class="attribute">#[<span class="ident">cfg</span>(<span class="ident">all</span>(<span class="ident">feature</span> <span class="op">=</span> <span class="string">"gimli-symbolize"</span>,
<span class="ident">unix</span>,
<span class="ident">target_os</span> <span class="op">=</span> <span class="string">"linux"</span>))]</span>
<span class="kw">extern</span> <span class="kw">crate</span> <span class="ident">addr2line</span>;
<span class="attribute">#[<span class="ident">cfg</span>(<span class="ident">all</span>(<span class="ident">feature</span> <span class="op">=</span> <span class="string">"gimli-symbolize"</span>,
<span class="ident">unix</span>,
<span class="ident">target_os</span> <span class="op">=</span> <span class="string">"linux"</span>))]</span>
<span class="kw">extern</span> <span class="kw">crate</span> <span class="ident">findshlibs</span>;
<span class="attribute">#[<span class="ident">allow</span>(<span class="ident">dead_code</span>)]</span> <span class="comment">// not used everywhere</span>
<span class="attribute">#[<span class="ident">cfg</span>(<span class="ident">unix</span>)]</span>
<span class="attribute">#[<span class="ident">macro_use</span>]</span>
<span class="kw">mod</span> <span class="ident">dylib</span>;
<span class="kw">pub</span> <span class="kw">use</span> <span class="ident">backtrace</span>::{<span class="ident">trace</span>, <span class="ident">Frame</span>};
<span class="kw">mod</span> <span class="ident">backtrace</span>;
<span class="kw">pub</span> <span class="kw">use</span> <span class="ident">symbolize</span>::{<span class="ident">resolve</span>, <span class="ident">Symbol</span>, <span class="ident">SymbolName</span>};
<span class="kw">mod</span> <span class="ident">symbolize</span>;
<span class="kw">pub</span> <span class="kw">use</span> <span class="ident">capture</span>::{<span class="ident">Backtrace</span>, <span class="ident">BacktraceFrame</span>, <span class="ident">BacktraceSymbol</span>};
<span class="kw">mod</span> <span class="ident">capture</span>;
<span class="attribute">#[<span class="ident">allow</span>(<span class="ident">dead_code</span>)]</span>
<span class="kw">struct</span> <span class="ident">Bomb</span> {
<span class="ident">enabled</span>: <span class="ident">bool</span>,
}
<span class="attribute">#[<span class="ident">allow</span>(<span class="ident">dead_code</span>)]</span>
<span class="kw">impl</span> <span class="ident">Drop</span> <span class="kw">for</span> <span class="ident">Bomb</span> {
<span class="kw">fn</span> <span class="ident">drop</span>(<span class="kw-2">&</span><span class="kw-2">mut</span> <span class="self">self</span>) {
<span class="kw">if</span> <span class="self">self</span>.<span class="ident">enabled</span> {
<span class="macro">panic</span><span class="macro">!</span>(<span class="string">"cannot panic during the backtrace function"</span>);
}
}
}
<span class="attribute">#[<span class="ident">allow</span>(<span class="ident">dead_code</span>)]</span>
<span class="kw">mod</span> <span class="ident">lock</span> {
<span class="kw">use</span> <span class="ident">std</span>::<span class="ident">cell</span>::<span class="ident">Cell</span>;
<span class="kw">use</span> <span class="ident">std</span>::<span class="ident">mem</span>;
<span class="kw">use</span> <span class="ident">std</span>::<span class="ident">sync</span>::{<span class="ident">Once</span>, <span class="ident">Mutex</span>, <span class="ident">MutexGuard</span>, <span class="ident">ONCE_INIT</span>};
<span class="kw">pub</span> <span class="kw">struct</span> <span class="ident">LockGuard</span>(<span class="ident">MutexGuard</span><span class="op"><</span><span class="lifetime">'static</span>, ()<span class="op">></span>);
<span class="kw">static</span> <span class="kw-2">mut</span> <span class="ident">LOCK</span>: <span class="kw-2">*</span><span class="kw-2">mut</span> <span class="ident">Mutex</span><span class="op"><</span>()<span class="op">></span> <span class="op">=</span> <span class="number">0</span> <span class="kw">as</span> <span class="kw-2">*</span><span class="kw-2">mut</span> _;
<span class="kw">static</span> <span class="ident">INIT</span>: <span class="ident">Once</span> <span class="op">=</span> <span class="ident">ONCE_INIT</span>;
<span class="macro">thread_local</span><span class="macro">!</span>(<span class="kw">static</span> <span class="ident">LOCK_HELD</span>: <span class="ident">Cell</span><span class="op"><</span><span class="ident">bool</span><span class="op">></span> <span class="op">=</span> <span class="ident">Cell</span>::<span class="ident">new</span>(<span class="bool-val">false</span>));
<span class="kw">impl</span> <span class="ident">Drop</span> <span class="kw">for</span> <span class="ident">LockGuard</span> {
<span class="kw">fn</span> <span class="ident">drop</span>(<span class="kw-2">&</span><span class="kw-2">mut</span> <span class="self">self</span>) {
<span class="ident">LOCK_HELD</span>.<span class="ident">with</span>(<span class="op">|</span><span class="ident">slot</span><span class="op">|</span> {
<span class="macro">assert</span><span class="macro">!</span>(<span class="ident">slot</span>.<span class="ident">get</span>());
<span class="ident">slot</span>.<span class="ident">set</span>(<span class="bool-val">false</span>);
});
}
}
<span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">lock</span>() <span class="op">-></span> <span class="prelude-ty">Option</span><span class="op"><</span><span class="ident">LockGuard</span><span class="op">></span> {
<span class="kw">if</span> <span class="ident">LOCK_HELD</span>.<span class="ident">with</span>(<span class="op">|</span><span class="ident">l</span><span class="op">|</span> <span class="ident">l</span>.<span class="ident">get</span>()) {
<span class="kw">return</span> <span class="prelude-val">None</span>
}
<span class="ident">LOCK_HELD</span>.<span class="ident">with</span>(<span class="op">|</span><span class="ident">s</span><span class="op">|</span> <span class="ident">s</span>.<span class="ident">set</span>(<span class="bool-val">true</span>));
<span class="kw">unsafe</span> {
<span class="ident">INIT</span>.<span class="ident">call_once</span>(<span class="op">||</span> {
<span class="ident">LOCK</span> <span class="op">=</span> <span class="ident">mem</span>::<span class="ident">transmute</span>(<span class="ident">Box</span>::<span class="ident">new</span>(<span class="ident">Mutex</span>::<span class="ident">new</span>(())));
});
<span class="prelude-val">Some</span>(<span class="ident">LockGuard</span>((<span class="kw-2">*</span><span class="ident">LOCK</span>).<span class="ident">lock</span>().<span class="ident">unwrap</span>()))
}
}
}
<span class="comment">// requires external synchronization</span>
<span class="attribute">#[<span class="ident">cfg</span>(<span class="ident">all</span>(<span class="ident">windows</span>, <span class="ident">feature</span> <span class="op">=</span> <span class="string">"dbghelp"</span>))]</span>
<span class="kw">unsafe</span> <span class="kw">fn</span> <span class="ident">dbghelp_init</span>() {
<span class="kw">use</span> <span class="ident">winapi</span>::<span class="ident">shared</span>::<span class="ident">minwindef</span>;
<span class="kw">use</span> <span class="ident">winapi</span>::<span class="ident">um</span>::{<span class="ident">dbghelp</span>, <span class="ident">processthreadsapi</span>};
<span class="kw">static</span> <span class="kw-2">mut</span> <span class="ident">INITIALIZED</span>: <span class="ident">bool</span> <span class="op">=</span> <span class="bool-val">false</span>;
<span class="kw">if</span> <span class="op">!</span><span class="ident">INITIALIZED</span> {
<span class="ident">dbghelp</span>::<span class="ident">SymInitializeW</span>(<span class="ident">processthreadsapi</span>::<span class="ident">GetCurrentProcess</span>(),
<span class="number">0</span> <span class="kw">as</span> <span class="kw-2">*</span><span class="kw-2">mut</span> _,
<span class="ident">minwindef</span>::<span class="ident">TRUE</span>);
<span class="ident">INITIALIZED</span> <span class="op">=</span> <span class="bool-val">true</span>;
}
}
</pre>
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