// Copyright 2012 The Rust Project Developers. See the COPYRIGHT
// file at the top-level directory of this distribution and at
// http://rust-lang.org/COPYRIGHT.
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.

use core::prelude::*;

use metadata::csearch;
use middle::astencode;
use middle::trans::base::{get_insn_ctxt};
use middle::trans::base::{impl_owned_self, impl_self, no_self};
use middle::trans::base::{trans_item, get_item_val, trans_fn};
use middle::trans::common::*;
use middle::ty;
use util::ppaux::ty_to_str;

use core::vec;
use syntax::ast;
use syntax::ast_map::path_name;
use syntax::ast_util::local_def;

// `translate` will be true if this function is allowed to translate the
// item and false otherwise. Currently, this parameter is set to false when
// translating default methods.
pub fn maybe_instantiate_inline(ccx: @CrateContext, fn_id: ast::def_id,
                                translate: bool)
    -> ast::def_id {
    let _icx = ccx.insn_ctxt("maybe_instantiate_inline");
    match ccx.external.find(&fn_id) {
      Some(&Some(node_id)) => {
        // Already inline
        debug!("maybe_instantiate_inline(%s): already inline as node id %d",
               ty::item_path_str(ccx.tcx, fn_id), node_id);
        local_def(node_id)
      }
      Some(&None) => fn_id, // Not inlinable
      None => { // Not seen yet
        match csearch::maybe_get_item_ast(
            ccx.tcx, fn_id,
            |a,b,c,d| {
                astencode::decode_inlined_item(a, b, ccx.maps,
                                               /*bad*/ copy c, d)
            }) {

          csearch::not_found => {
            ccx.external.insert(fn_id, None);
            fn_id
          }
          csearch::found(ast::ii_item(item)) => {
            ccx.external.insert(fn_id, Some(item.id));
            ccx.stats.n_inlines += 1;
            if translate { trans_item(ccx, *item); }
            local_def(item.id)
          }
          csearch::found(ast::ii_foreign(item)) => {
            ccx.external.insert(fn_id, Some(item.id));
            local_def(item.id)
          }
          csearch::found_parent(parent_id, ast::ii_item(item)) => {
            ccx.external.insert(parent_id, Some(item.id));
            let mut my_id = 0;
            match item.node {
              ast::item_enum(_, _) => {
                let vs_here = ty::enum_variants(ccx.tcx, local_def(item.id));
                let vs_there = ty::enum_variants(ccx.tcx, parent_id);
                for vec::each2(*vs_here, *vs_there) |here, there| {
                    if there.id == fn_id { my_id = here.id.node; }
                    ccx.external.insert(there.id, Some(here.id.node));
                }
              }
              _ => ccx.sess.bug(~"maybe_instantiate_inline: item has a \
                    non-enum parent")
            }
            if translate { trans_item(ccx, *item); }
            local_def(my_id)
          }
          csearch::found_parent(_, _) => {
              ccx.sess.bug(~"maybe_get_item_ast returned a found_parent \
               with a non-item parent");
          }
          csearch::found(ast::ii_method(impl_did, mth)) => {
            ccx.stats.n_inlines += 1;
            ccx.external.insert(fn_id, Some(mth.id));
            let impl_tpt = ty::lookup_item_type(ccx.tcx, impl_did);
            let num_type_params =
                impl_tpt.generics.type_param_defs.len() +
                mth.generics.ty_params.len();
            if translate && num_type_params == 0 {
                let llfn = get_item_val(ccx, mth.id);
                let path = vec::append(
                    ty::item_path(ccx.tcx, impl_did),
                    ~[path_name(mth.ident)]);
                let self_kind = match mth.self_ty.node {
                    ast::sty_static => no_self,
                    _ => {
                        let self_ty = ty::node_id_to_type(ccx.tcx,
                                                          mth.self_id);
                        debug!("calling inline trans_fn with self_ty %s",
                               ty_to_str(ccx.tcx, self_ty));
                        match mth.self_ty.node {
                            ast::sty_value => impl_owned_self(self_ty),
                            _ => impl_self(self_ty),
                        }
                    }
                };
                trans_fn(ccx,
                         path,
                         &mth.decl,
                         &mth.body,
                         llfn,
                         self_kind,
                         None,
                         mth.id,
                         Some(impl_did));
            }
            local_def(mth.id)
          }
          csearch::found(ast::ii_dtor(ref dtor, _, _, _)) => {
              ccx.external.insert(fn_id, Some((*dtor).node.id));
              local_def((*dtor).node.id)
          }
        }
      }
    }
}