388 lines
11 KiB
Rust
388 lines
11 KiB
Rust
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/*
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The compiler code necessary to implement the #[auto_serialize]
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extension. The idea here is that type-defining items may be tagged
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with #[auto_serialize], which will cause us to generate a little
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companion module with the same name as the item.
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For example, a type like:
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type node_id = uint;
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would generate a companion module like:
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mod node_id {
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use std;
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import std::serialization::serializer;
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import std::serialization::deserializer;
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fn serialize<S: serializer>(s: S, v: node_id) {
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s.emit_uint(v);
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}
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fn deserializer<D: deserializer>(d: D) -> node_id {
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d.read_uint()
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}
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}
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Other interesting scenarios are whe the item has type parameters or
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references other non-built-in types. A type definition like:
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type spanned<T> = {node: T, span: span};
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would yield a helper module like:
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mod spanned {
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use std;
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import std::serialization::serializer;
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import std::serialization::deserializer;
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fn serialize<S: serializer,T>(s: S, t: fn(T), v: spanned<T>) {
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s.emit_rec(2u) {||
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s.emit_rec_field("node", 0u) {||
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t(s.node);
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};
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s.emit_rec_field("span", 1u) {||
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span::serialize(s, s.span);
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};
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}
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}
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fn deserializer<D: deserializer>(d: D, t: fn() -> T) -> node_id {
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d.read_rec(2u) {||
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{node: d.read_rec_field("node", 0u, t),
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span: d.read_rec_field("span", 1u) {||span::deserialize(d)}}
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}
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}
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}
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In general, the code to serialize an instance `v` of a non-built-in
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type a::b::c<T0,...,Tn> looks like:
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a::b::c::serialize(s, {|v| c_T0}, ..., {|v| c_Tn}, v)
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where `c_Ti` is the code to serialize an instance `v` of the type
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`Ti`.
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Similarly, the code to deserialize an instance of a non-built-in type
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`a::b::c<T0,...,Tn>` using the deserializer `d` looks like:
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a::b::c::deserialize(d, {|| c_T0}, ..., {|| c_Tn})
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where `c_Ti` is the code to deserialize an instance of `Ti` using the
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deserializer `d`.
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TODO--Hygiene. Search for "__" strings.
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*/
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import base::*;
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import driver::session::session;
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import codemap::span;
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import std::map;
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export expand_auto_serialize;
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enum ser_cx = {
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ext_cx: ext_ctxt,
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tps: map::map<str, fn@(@ast::expr) -> [@ast::stmt]>
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};
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fn expand_auto_serialize(cx: ext_ctxt,
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span: span,
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mitem: ast::meta_item,
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in_items: [@ast::item]) -> [@ast::item] {
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vec::flat_map(in_items) {|in_item|
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alt in_item.node {
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ast::item_ty(ty, tps) {
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[in_item, ty_module(cx, in_item.ident, ty, tps)]
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}
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ast::item_enum(variants, tps) {
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[in_item, enum_module(cx, in_item.ident, variants, tps)]
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}
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_ {
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cx.session().span_err(span, "#[auto_serialize] can only be \
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applied to type and enum \
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definitions");
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[in_item]
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}
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}
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}
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}
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impl helpers for ser_cx {
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fn session() -> session { self.ext_cx.session() }
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fn next_id() -> ast::node_id { self.session().next_node_id() }
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fn path(span: span, strs: [str]) -> @ast::path {
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@{node: {global: false,
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idents: strs + ["serialize"],
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types: []},
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span: span}
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}
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fn expr(span: span, node: ast::expr_) -> @ast::expr {
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@{id: self.next_id(), node: node, span: span}
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}
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fn ty_path(span: span, strs: [str]) -> @ast::ty {
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@{node: ast::ty_path(self.path(span, strs), self.next_id()),
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span: span}
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}
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fn var_ref(span: span, name: str) -> @ast::expr {
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self.expr(span, ast::expr_path(self.path(span, [name])))
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}
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fn blk(span: span, stmts: [@ast::stmt]) -> ast::blk {
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{node: {view_items: [],
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stmts: stmts,
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expr: none,
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id: self.next_id(),
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rules: ast::default_blk},
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span: span}
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}
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fn binder_pat(span: span, nm: str) -> @ast::pat {
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let path = @{node: {global: false,
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idents: [nm],
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types: []},
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span: span};
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@{id: self.next_id(),
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node: ast::pat_ident(path, none),
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span: span}
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}
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fn stmt(expr: @ast::expr) -> @ast::stmt {
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@{node: ast::stmt_semi(expr, self.next_id()),
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span: expr.span}
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}
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fn alt_stmt(arms: [ast::arm], span: span, -v: @ast::expr) -> @ast::stmt {
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self.stmt(
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self.expr(
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span,
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ast::expr_alt(v, arms, ast::alt_exhaustive)))
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}
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fn clone(v: @ast::expr) -> @ast::expr {
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let fld = fold::make_fold({
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new_id: {|_id| self.next_id()}
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with *fold::default_ast_fold()
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});
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fld.fold_expr(v)
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}
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fn clone_ty_param(v: ast::ty_param) -> ast::ty_param {
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let fld = fold::make_fold({
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new_id: {|_id| self.next_id()}
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with *fold::default_ast_fold()
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});
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fold::fold_ty_param(v, fld)
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}
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fn at(span: span, expr: @ast::expr) -> @ast::expr {
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fn repl_sp(old_span: span, repl_span: span, with_span: span) -> span {
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if old_span == repl_span {
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with_span
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} else {
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old_span
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}
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}
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let fld = fold::make_fold({
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new_span: repl_sp(_, ast_util::dummy_sp(), span)
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with *fold::default_ast_fold()
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});
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fld.fold_expr(expr)
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}
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}
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fn serialize_path(cx: ser_cx, path: @ast::path, -s: @ast::expr, -v: @ast::expr)
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-> [@ast::stmt] {
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let ext_cx = cx.ext_cx;
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// We want to take a path like a::b::c<...> and generate a call
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// like a::b::c::serialize(s, ...), as described above.
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let callee =
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cx.expr(
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path.span,
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ast::expr_path(
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cx.path(path.span, path.node.idents + ["serialize"])));
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let ty_args = vec::map(path.node.types) {|ty|
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let sv = serialize_ty(cx, ty, s, #ast(expr){"__v"});
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cx.at(ty.span, #ast(expr){"{|__v| $(sv)}"})
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};
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[cx.stmt(
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cx.expr(
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path.span,
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ast::expr_call(callee, [s] + ty_args + [v], false)))]
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}
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fn serialize_variant(cx: ser_cx,
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tys: [@ast::ty],
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span: span,
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-s: @ast::expr,
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pfn: fn([@ast::pat]) -> ast::pat_) -> ast::arm {
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let vnames = vec::init_fn(vec::len(tys)) {|i| #fmt["__v%u", i]};
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let pats = vec::init_fn(vec::len(tys)) {|i|
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cx.binder_pat(tys[i].span, vnames[i])
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};
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let pat: @ast::pat = @{id: cx.next_id(), node: pfn(pats), span: span};
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let stmts = vec::init_fn(vec::len(tys)) {|i|
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let v = cx.var_ref(span, vnames[i]);
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serialize_ty(cx, tys[i], cx.clone(s), v)
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};
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{pats: [pat], guard: none, body: cx.blk(span, vec::concat(stmts))}
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}
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fn serialize_ty(cx: ser_cx, ty: @ast::ty, -s: @ast::expr, -v: @ast::expr)
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-> [@ast::stmt] {
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let ext_cx = cx.ext_cx;
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alt ty.node {
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ast::ty_nil | ast::ty_bot {
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[]
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}
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ast::ty_box(mt) |
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ast::ty_uniq(mt) |
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ast::ty_ptr(mt) {
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serialize_ty(cx, mt.ty, s, #ast(expr){"*$(v)"})
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}
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ast::ty_rec(flds) {
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vec::flat_map(flds) {|fld|
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let vf = cx.expr(
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fld.span,
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ast::expr_field(cx.clone(v), fld.node.ident, []));
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serialize_ty(cx, fld.node.mt.ty, cx.clone(s), vf)
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}
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}
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ast::ty_fn(_, _) {
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cx.session().span_err(
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ty.span, #fmt["Cannot serialize function types"]);
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[]
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}
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ast::ty_tup(tys) {
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// Generate code like
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//
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// alt v {
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// (v1, v2, v3) {
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// .. serialize v1, v2, v3 ..
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// }
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// };
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let arms = [
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serialize_variant(cx, tys, ty.span, s,
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{|pats| ast::pat_tup(pats)})
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];
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[cx.alt_stmt(arms, ty.span, v)]
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}
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ast::ty_path(path, _) {
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if vec::len(path.node.idents) == 1u &&
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vec::is_empty(path.node.types) {
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let ident = path.node.idents[0];
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alt cx.tps.find(ident) {
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some(f) { f(v) }
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none { serialize_path(cx, path, s, v) }
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}
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} else {
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serialize_path(cx, path, s, v)
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}
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}
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ast::ty_constr(ty, _) {
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serialize_ty(cx, ty, s, v)
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}
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ast::ty_mac(_) {
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cx.session().span_err(
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ty.span, #fmt["Cannot serialize macro types"]);
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[]
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}
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ast::ty_infer {
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cx.session().span_err(
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ty.span, #fmt["Cannot serialize inferred types"]);
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[]
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}
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ast::ty_vec(mt) {
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let ser_e =
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cx.expr(
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ty.span,
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expr_block(
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cx.blk(
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ty.span,
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serialize_ty(
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cx, mt.ty,
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cx.clone(s),
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cx.at(
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ty.span,
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#ast(expr){__e})))));
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[#ast(stmt){ $(s).emit_from_vec($(v), {|__e| $(ser_e) }) }]
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}
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}
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}
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fn ty_module(ext_cx: ext_ctxt, name: str, -ty: @ast::ty, tps: [ast::ty_param])
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-> @ast::item {
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let cx = ser_cx({ext_cx: ext_cx, tps: map::new_str_hash()});
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let ser_inputs: [ast::arg] =
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[{mode: ast::expl(ast::by_ref),
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ty: cx.ty_path(ty.span, ["__S"]),
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ident: "__s",
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id: cx.next_id()},
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{mode: ast::expl(ast::by_ref),
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ty: ty,
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ident: "__v",
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id: cx.next_id()}] +
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vec::map(tps, {|tp|
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{mode: ast::expl(ast::by_ref),
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ty: cx.ty_path(ty.span, [tp.ident]),
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ident: "__v",
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id: cx.next_id()}});
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let ser_bnds = @[ast::bound_iface(cx.ty_path(ty.span,
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["__std", "serialization",
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"serializer"]))];
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let ser_tps: [ast::ty_param] =
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[{ident: "__S",
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id: cx.next_id(),
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bounds: ser_bnds}] +
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vec::map(tps) {|tp| cx.clone_ty_param(tp) };
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let ser_output: @ast::ty = @{node: ast::ty_nil,
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span: ty.span};
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let ser_blk = cx.blk(ty.span,
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serialize_ty(cx, ty,
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#ast(expr){"__s"}, #ast(expr){"__v"}));
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@{ident: "serialize",
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attrs: [],
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id: cx.next_id(),
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node: ast::item_fn({inputs: ser_inputs,
|
||
|
|
output: ser_output,
|
||
|
|
purity: ast::impure_fn,
|
||
|
|
cf: ast::return_val,
|
||
|
|
constraints: []},
|
||
|
|
ser_tps,
|
||
|
|
ser_blk),
|
||
|
|
span: ty.span}
|
||
|
|
}
|
||
|
|
|
||
|
|
fn enum_module(cx: ext_ctxt, name: str,
|
||
|
|
variants: [ast::variant], tps: [ast::ty_param])
|
||
|
|
-> @ast::item {
|
||
|
|
|
||
|
|
}
|