Pull codegen into it's own crate

2026-04-23 03:38:00 +00:00 · 2015-05-17 23:11:08 -07:00
parent 426394cd7b
commit 24ac61f9f2
8 changed files with 42 additions and 26 deletions
@@ -0,0 +1,133 @@
+use std::collections::HashMap;
+
+use syntax::ast;
+use syntax::attr;
+use syntax::ext::base::ExtCtxt;
+use syntax::ptr::P;
+
+use aster;
+
+use super::attr::FieldAttrs;
+
+enum Rename<'a> {
+    None,
+    Global(&'a ast::Lit),
+    Format(HashMap<P<ast::Expr>, &'a ast::Lit>)
+}
+
+fn rename<'a>(
+    builder: &aster::AstBuilder,
+    mi: &'a ast::MetaItem,
+    ) -> Option<Rename<'a>>
+{
+    match mi.node {
+        ast::MetaNameValue(ref n, ref lit) => {
+            if n == &"rename" {
+                Some(Rename::Global(lit))
+            } else {
+                None
+            }
+        },
+        ast::MetaList(ref n, ref items) => {
+            if n == &"rename" {
+                let mut m = HashMap::new();
+                m.extend(
+                    items.iter()
+                        .filter_map(
+                            |item|
+                            match item.node {
+                                ast::MetaNameValue(ref n, ref lit) =>
+                                    Some((builder.expr().str(n),
+                                          lit)),
+                                _ => None
+                            }));
+                Some(Rename::Format(m))
+            } else {
+                None
+            }
+        },
+        _ => None
+    }
+}
+
+pub fn default_value(mi: &ast::MetaItem) -> bool {
+    if let ast::MetaItem_::MetaWord(ref n) = mi.node {
+        n == &"default"
+    } else {
+        false
+    }
+}
+
+fn field_attrs<'a>(
+    builder: &aster::AstBuilder,
+    field: &'a ast::StructField,
+) -> (Rename<'a>, bool) {
+    field.node.attrs.iter()
+        .find(|sa| {
+            if let ast::MetaList(ref n, _) = sa.node.value.node {
+                n == &"serde"
+            } else {
+                false
+            }
+        })
+        .and_then(|sa| {
+            if let ast::MetaList(_, ref vals) = sa.node.value.node {
+                attr::mark_used(&sa);
+                Some((vals.iter()
+                      .fold(None, |v, mi| v.or(rename(builder, mi)))
+                      .unwrap_or(Rename::None),
+                      vals.iter().any(|mi| default_value(mi))))
+            } else {
+                Some((Rename::None, false))
+            }
+        })
+        .unwrap_or((Rename::None, false))
+}
+
+pub fn struct_field_attrs(
+    cx: &ExtCtxt,
+    builder: &aster::AstBuilder,
+    struct_def: &ast::StructDef,
+) -> Vec<FieldAttrs> {
+    struct_def.fields.iter()
+        .map(|field| {
+            match field_attrs(builder, field) {
+                (Rename::Global(rename), default_value) =>
+                    FieldAttrs::new(
+                        default_value,
+                        builder.expr().build_lit(P(rename.clone()))),
+                (Rename::Format(renames), default_value) => {
+                    let mut res = HashMap::new();
+                    res.extend(
+                        renames.into_iter()
+                            .map(|(k,v)|
+                                 (k, builder.expr().build_lit(P(v.clone())))));
+                    FieldAttrs::new_with_formats(
+                        default_value,
+                        default_field_name(cx, builder, field.node.kind),
+                        res)
+                },
+                (Rename::None, default_value) => {
+                    FieldAttrs::new(
+                        default_value,
+                        default_field_name(cx, builder, field.node.kind))
+                }
+            }
+        })
+        .collect()
+}
+
+fn default_field_name(
+    cx: &ExtCtxt,
+    builder: &aster::AstBuilder,
+    kind: ast::StructFieldKind,
+) -> P<ast::Expr> {
+    match kind {
+        ast::NamedField(name, _) => {
+            builder.expr().str(name)
+        }
+        ast::UnnamedField(_) => {
+            cx.bug("struct has named and unnamed fields")
+        }
+    }
+}