208 lines
6.5 KiB
Rust
208 lines
6.5 KiB
Rust
// Copyright 2012 The Rust Project Developers. See the COPYRIGHT
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// file at the top-level directory of this distribution and at
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// http://rust-lang.org/COPYRIGHT.
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//
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// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
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// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
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// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
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// option. This file may not be copied, modified, or distributed
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// except according to those terms.
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use std::option;
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use syntax::{ast, fold, attr};
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type in_cfg_pred = @fn(attrs: &[ast::attribute]) -> bool;
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struct Context {
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in_cfg: in_cfg_pred
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}
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// Support conditional compilation by transforming the AST, stripping out
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// any items that do not belong in the current configuration
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pub fn strip_unconfigured_items(crate: @ast::crate) -> @ast::crate {
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do strip_items(crate) |attrs| {
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in_cfg(crate.node.config, attrs)
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}
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}
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pub fn strip_items(crate: &ast::crate, in_cfg: in_cfg_pred)
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-> @ast::crate {
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let ctxt = @Context { in_cfg: in_cfg };
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let precursor = @fold::AstFoldFns {
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fold_mod: |a,b| fold_mod(ctxt, a, b),
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fold_block: |a,b| fold_block(ctxt, a, b),
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fold_foreign_mod: |a,b| fold_foreign_mod(ctxt, a, b),
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fold_item_underscore: |a,b| {
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// Bad copy.
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fold_item_underscore(ctxt, copy a, b)
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},
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.. *fold::default_ast_fold()};
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let fold = fold::make_fold(precursor);
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@fold.fold_crate(crate)
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}
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fn filter_item(cx: @Context, item: @ast::item) ->
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Option<@ast::item> {
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if item_in_cfg(cx, item) { option::Some(item) } else { option::None }
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}
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fn filter_view_item<'r>(cx: @Context, view_item: &'r ast::view_item)-> Option<&'r ast::view_item> {
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if view_item_in_cfg(cx, view_item) {
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option::Some(view_item)
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} else {
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option::None
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}
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}
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fn fold_mod(cx: @Context, m: &ast::_mod, fld: @fold::ast_fold) -> ast::_mod {
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let filtered_items = do m.items.iter().filter_map |a| {
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filter_item(cx, *a).chain(|x| fld.fold_item(x))
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}.collect();
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let filtered_view_items = do m.view_items.iter().filter_map |a| {
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filter_view_item(cx, a).map(|&x| fld.fold_view_item(x))
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}.collect();
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ast::_mod {
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view_items: filtered_view_items,
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items: filtered_items
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}
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}
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fn filter_foreign_item(cx: @Context, item: @ast::foreign_item) ->
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Option<@ast::foreign_item> {
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if foreign_item_in_cfg(cx, item) {
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option::Some(item)
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} else { option::None }
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}
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fn fold_foreign_mod(
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cx: @Context,
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nm: &ast::foreign_mod,
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fld: @fold::ast_fold
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) -> ast::foreign_mod {
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let filtered_items = nm.items.iter().filter_map(|a| filter_foreign_item(cx, *a)).collect();
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let filtered_view_items = do nm.view_items.iter().filter_map |a| {
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filter_view_item(cx, a).map(|&x| fld.fold_view_item(x))
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}.collect();
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ast::foreign_mod {
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sort: nm.sort,
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abis: nm.abis,
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view_items: filtered_view_items,
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items: filtered_items
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}
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}
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fn fold_item_underscore(cx: @Context, item: &ast::item_,
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fld: @fold::ast_fold) -> ast::item_ {
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let item = match *item {
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ast::item_impl(ref a, ref b, ref c, ref methods) => {
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let methods = methods.iter().filter(|m| method_in_cfg(cx, **m))
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.transform(|x| *x).collect();
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ast::item_impl(/*bad*/ copy *a, /*bad*/ copy *b, /*bad*/ copy *c, methods)
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}
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ast::item_trait(ref a, ref b, ref methods) => {
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let methods = methods.iter().filter(|m| trait_method_in_cfg(cx, *m) )
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.transform(|x| /* bad */copy *x).collect();
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ast::item_trait(/*bad*/copy *a, /*bad*/copy *b, methods)
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}
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ref item => /*bad*/ copy *item
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};
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fold::noop_fold_item_underscore(&item, fld)
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}
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fn filter_stmt(cx: @Context, stmt: @ast::stmt) ->
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Option<@ast::stmt> {
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match stmt.node {
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ast::stmt_decl(decl, _) => {
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match decl.node {
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ast::decl_item(item) => {
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if item_in_cfg(cx, item) {
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option::Some(stmt)
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} else { option::None }
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}
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_ => option::Some(stmt)
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}
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}
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_ => option::Some(stmt)
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}
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}
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fn fold_block(
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cx: @Context,
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b: &ast::blk,
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fld: @fold::ast_fold
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) -> ast::blk {
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let resulting_stmts = do b.stmts.iter().filter_map |a| {
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filter_stmt(cx, *a).chain(|stmt| fld.fold_stmt(stmt))
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}.collect();
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let filtered_view_items = do b.view_items.iter().filter_map |a| {
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filter_view_item(cx, a).map(|&x| fld.fold_view_item(x))
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}.collect();
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ast::blk {
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view_items: filtered_view_items,
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stmts: resulting_stmts,
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expr: b.expr.map(|x| fld.fold_expr(*x)),
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id: b.id,
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rules: b.rules,
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span: b.span,
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}
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}
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fn item_in_cfg(cx: @Context, item: @ast::item) -> bool {
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return (cx.in_cfg)(/*bad*/copy item.attrs);
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}
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fn foreign_item_in_cfg(cx: @Context, item: @ast::foreign_item) -> bool {
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return (cx.in_cfg)(/*bad*/copy item.attrs);
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}
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fn view_item_in_cfg(cx: @Context, item: &ast::view_item) -> bool {
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return (cx.in_cfg)(item.attrs);
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}
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fn method_in_cfg(cx: @Context, meth: @ast::method) -> bool {
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return (cx.in_cfg)(/*bad*/copy meth.attrs);
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}
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fn trait_method_in_cfg(cx: @Context, meth: &ast::trait_method) -> bool {
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match *meth {
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ast::required(ref meth) => (cx.in_cfg)(/*bad*/copy meth.attrs),
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ast::provided(@ref meth) => (cx.in_cfg)(/*bad*/copy meth.attrs)
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}
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}
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// Determine if an item should be translated in the current crate
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// configuration based on the item's attributes
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fn in_cfg(cfg: &[@ast::meta_item], attrs: &[ast::attribute]) -> bool {
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metas_in_cfg(cfg, attr::attr_metas(attrs))
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}
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pub fn metas_in_cfg(cfg: &[@ast::meta_item],
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metas: &[@ast::meta_item]) -> bool {
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// The "cfg" attributes on the item
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let cfg_metas = attr::find_meta_items_by_name(metas, "cfg");
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// Pull the inner meta_items from the #[cfg(meta_item, ...)] attributes,
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// so we can match against them. This is the list of configurations for
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// which the item is valid
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let cfg_metas = cfg_metas.consume_iter()
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.filter_map(|i| attr::get_meta_item_list(i))
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.collect::<~[~[@ast::meta_item]]>();
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if cfg_metas.iter().all(|c| c.is_empty()) { return true; }
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cfg_metas.iter().any(|cfg_meta| {
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cfg_meta.iter().all(|cfg_mi| {
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match cfg_mi.node {
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ast::meta_list(s, ref it) if "not" == s
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=> it.iter().all(|mi| !attr::contains(cfg, *mi)),
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_ => attr::contains(cfg, *cfg_mi)
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}
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})
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})
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}
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