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| <br> |
| <p><strong>Typed distributed plugin registration.</strong></p> |
| <p>This crate provides a way to set up a plugin registry into which plugins |
| can be registered from any source file linked into your application. There |
| does not need to be a central list of all the plugins.</p> |
| <h2 id="examples"><a href="#examples">Examples</a></h2> |
| <p>Suppose we are writing a command line flags library and want to allow any |
| source file in the application to register command line flags that are |
| relevant to it.</p> |
| <p>This is the flag registration style used by <a href="https://gflags.github.io/gflags/">gflags</a> and is better suited |
| for large scale development than maintaining a single central list of flags, |
| as the central list would become an endless source of merge conflicts in an |
| application developed simultaneously by thousands of developers.</p> |
| <h3 id="instantiating-the-plugin-registry"><a href="#instantiating-the-plugin-registry">Instantiating the plugin registry</a></h3> |
| <p>Let’s use a <code>struct Flag</code> as the plugin type, which will contain the short |
| name of the flag like <code>-v</code>, the full name like <code>--verbose</code>, and maybe other |
| information like argument type and help text. We instantiate a plugin |
| registry with an invocation of <code>inventory::collect!</code>.</p> |
| |
| <div class="example-wrap"><pre class="rust rust-example-rendered"><code><span class="kw">pub struct </span>Flag { |
| short: char, |
| name: <span class="kw-2">&</span><span class="lifetime">'static </span>str, |
| <span class="comment">/* ... */ |
| </span>} |
| |
| <span class="kw">impl </span>Flag { |
| <span class="kw">pub fn </span>new(short: char, name: <span class="kw-2">&</span><span class="lifetime">'static </span>str) -> <span class="self">Self </span>{ |
| Flag { short, name } |
| } |
| } |
| |
| <span class="macro">inventory::collect!</span>(Flag);</code></pre></div> |
| <p>This <code>collect!</code> call must be in the same crate that defines the plugin type. |
| This macro does not “run” anything so place it outside of any function body.</p> |
| <h3 id="registering-plugins"><a href="#registering-plugins">Registering plugins</a></h3> |
| <p>Now any crate with access to the <code>Flag</code> type can register flags as a plugin. |
| Plugins can be registered by the same crate that declares the plugin type, |
| or by any downstream crate.</p> |
| |
| <div class="example-wrap"><pre class="rust rust-example-rendered"><code><span class="macro">inventory::submit! </span>{ |
| Flag::new(<span class="string">'v'</span>, <span class="string">"verbose"</span>) |
| }</code></pre></div> |
| <p>The <code>submit!</code> macro does not “run” anything so place it outside of any |
| function body. In particular, note that all <code>submit!</code> invocations across all |
| source files linked into your application all take effect simultaneously. A |
| <code>submit!</code> invocation is not a statement that needs to be called from <code>main</code> |
| in order to execute.</p> |
| <h3 id="iterating-over-plugins"><a href="#iterating-over-plugins">Iterating over plugins</a></h3> |
| <p>The value <code>inventory::iter::<T></code> is an iterator with element type <code>&'static T</code> that iterates over all plugins registered of type <code>T</code>.</p> |
| |
| <div class="example-wrap"><pre class="rust rust-example-rendered"><code><span class="kw">for </span>flag <span class="kw">in </span>inventory::iter::<Flag> { |
| <span class="macro">println!</span>(<span class="string">"-{}, --{}"</span>, flag.short, flag.name); |
| }</code></pre></div> |
| <p>There is no guarantee about the order that plugins of the same type are |
| visited by the iterator. They may be visited in any order.</p> |
| </div></details><h2 id="macros" class="small-section-header"><a href="#macros">Macros</a></h2><div class="item-table"><div class="item-row"><div class="item-left module-item"><a class="macro" href="macro.collect.html" title="inventory::collect macro">collect</a></div><div class="item-right docblock-short">Associate a plugin registry with the specified type.</div></div><div class="item-row"><div class="item-left module-item"><a class="macro" href="macro.submit.html" title="inventory::submit macro">submit</a></div><div class="item-right docblock-short">Enter an element into the plugin registry corresponding to its type.</div></div></div><h2 id="traits" class="small-section-header"><a href="#traits">Traits</a></h2><div class="item-table"><div class="item-row"><div class="item-left module-item"><a class="trait" href="trait.Collect.html" title="inventory::Collect trait">Collect</a></div><div class="item-right docblock-short">Trait bound corresponding to types that can be iterated by inventory::iter.</div></div></div><h2 id="types" class="small-section-header"><a href="#types">Type Definitions</a></h2><div class="item-table"><div class="item-row"><div class="item-left module-item"><a class="type" href="type.iter.html" title="inventory::iter type">iter</a></div><div class="item-right docblock-short">An iterator over plugins registered of a given type.</div></div></div></section></div></main><div id="rustdoc-vars" data-root-path="../" data-current-crate="inventory" data-themes="ayu,dark,light" data-resource-suffix="" data-rustdoc-version="1.66.0-nightly (5c8bff74b 2022-10-21)" ></div></body></html> |
