Use more encapsulation for metadata::cstore

3 files changed, 69 insertions, 25 deletions

diff --git a/src/comp/metadata/cstore.rs b/src/comp/metadata/cstore.rs
index dfa44909ce2..2812dd53307 100644
--- a/src/comp/metadata/cstore.rs
+++ b/src/comp/metadata/cstore.rs
@@ -6,6 +6,23 @@ import std::vec;
 import std::str;
 import syntax::ast;
 
+export cstore;
+export cnum_map;
+export crate_metadata;
+export mk_cstore;
+export get_crate_data;
+export set_crate_data;
+export have_crate_data;
+export iter_crate_data;
+export add_used_crate_file;
+export get_used_crate_files;
+export add_used_library;
+export get_used_libraries;
+export add_used_link_args;
+export get_used_link_args;
+export add_use_stmt_cnum;
+export get_use_stmt_cnum;
+
 // A map from external crate numbers (as decoded from some crate file) to
 // local crate numbers (as generated during this session). Each external
 // crate may refer to types in other external crates, and each has their
@@ -16,73 +33,100 @@ type crate_metadata = rec(str name,
                           vec[u8] data,
                           cnum_map cnum_map);
 
+// This is a bit of an experiment at encapsulating the data in cstore. By
+// keeping all the data in a non-exported tag variant, it's impossible for
+// other modules to access the cstore's private data. This could also be
+// achieved with an obj, but at the expense of a vtable. Not sure if this is a
+// good pattern or not.
+tag cstore {
+    private(cstore_private);
+}
+
+type cstore_private = @rec(map::hashmap[ast::crate_num, crate_metadata] metas,
+                           use_crate_map use_crate_map,
+                           mutable vec[str] used_crate_files,
+                           mutable vec[str] used_libraries,
+                           mutable vec[str] used_link_args);
+
 // Map from node_id's of local use statements to crate numbers
 type use_crate_map = map::hashmap[ast::node_id, ast::crate_num];
 
-type cstore = @rec(map::hashmap[ast::crate_num, crate_metadata] metas,
-                   use_crate_map use_crate_map,
-                   mutable vec[str] used_crate_files,
-                   mutable vec[str] used_libraries,
-                   mutable vec[str] used_link_args);
+// Internal method to retrieve the data from the cstore
+fn p(&cstore cstore) -> cstore_private {
+    alt (cstore) {
+        case (private(?p)) { p }
+    }
+}
 
 fn mk_cstore() -> cstore {
     auto meta_cache = map::new_int_hash[crate_metadata]();
     auto crate_map = map::new_int_hash[ast::crate_num]();
-    ret @rec(metas = meta_cache,
-             use_crate_map = crate_map,
-             mutable used_crate_files = [],
-             mutable used_libraries = [],
-             mutable used_link_args = []);
+    ret private(@rec(metas = meta_cache,
+                     use_crate_map = crate_map,
+                     mutable used_crate_files = [],
+                     mutable used_libraries = [],
+                     mutable used_link_args = []));
 }
 
 fn get_crate_data(&cstore cstore, ast::crate_num cnum) -> crate_metadata {
-    ret cstore.metas.get(cnum);
+    ret p(cstore).metas.get(cnum);
 }
 
 fn set_crate_data(&cstore cstore, ast::crate_num cnum, &crate_metadata data) {
-    cstore.metas.insert(cnum, data);
+    p(cstore).metas.insert(cnum, data);
 }
 
 fn have_crate_data(&cstore cstore, ast::crate_num cnum) -> bool {
-    ret cstore.metas.contains_key(cnum);
+    ret p(cstore).metas.contains_key(cnum);
+}
+
+iter iter_crate_data(&cstore cstore) -> @tup(ast::crate_num, crate_metadata) {
+    for each (@tup(ast::crate_num, crate_metadata) kv
+              in p(cstore).metas.items()) {
+        put kv;
+    }
 }
 
 fn add_used_crate_file(&cstore cstore, &str lib) {
-    if (!vec::member(lib, cstore.used_crate_files)) {
-        cstore.used_crate_files += [lib];
+    if (!vec::member(lib, p(cstore).used_crate_files)) {
+        p(cstore).used_crate_files += [lib];
     }
 }
 
 fn get_used_crate_files(&cstore cstore) -> vec[str] {
-    ret cstore.used_crate_files;
+    ret p(cstore).used_crate_files;
 }
 
 fn add_used_library(&cstore cstore, &str lib) -> bool {
     if (lib == "") { ret false; }
 
-    if (vec::member(lib, cstore.used_libraries)) {
+    if (vec::member(lib, p(cstore).used_libraries)) {
         ret false;
     }
 
-    cstore.used_libraries += [lib];
+    p(cstore).used_libraries += [lib];
     ret true;
 }
 
 fn get_used_libraries(&cstore cstore) -> vec[str] {
-    ret cstore.used_libraries;
+    ret p(cstore).used_libraries;
 }
 
 fn add_used_link_args(&cstore cstore, &str args) {
-    cstore.used_link_args += str::split(args, ' ' as u8);
+    p(cstore).used_link_args += str::split(args, ' ' as u8);
 }
 
 fn get_used_link_args(&cstore cstore) -> vec[str] {
-    ret cstore.used_link_args;
+    ret p(cstore).used_link_args;
 }
 
 fn add_use_stmt_cnum(&cstore cstore, ast::node_id use_id,
                      ast::crate_num cnum) {
-    cstore.use_crate_map.insert(use_id, cnum);
+    p(cstore).use_crate_map.insert(use_id, cnum);
+}
+
+fn get_use_stmt_cnum(&cstore cstore, ast::node_id use_id) -> ast::crate_num {
+    ret p(cstore).use_crate_map.get(use_id);
 }
 
 // Local Variables:
diff --git a/src/comp/metadata/encoder.rs b/src/comp/metadata/encoder.rs
index 89634d233bf..c1c48bcd18e 100644
--- a/src/comp/metadata/encoder.rs
+++ b/src/comp/metadata/encoder.rs
@@ -528,7 +528,7 @@ fn encode_crate_deps(&ebml::writer ebml_w, &cstore::cstore cstore) {
 
         // Pull the cnums and names out of cstore
         let vec[mutable numname] pairs = [mutable];
-        for each (hashkv hashkv in cstore.metas.items()) {
+        for each (hashkv hashkv in cstore::iter_crate_data(cstore)) {
             pairs += [mutable tup(hashkv._0, hashkv._1.name)];
         }
 
diff --git a/src/comp/middle/resolve.rs b/src/comp/middle/resolve.rs
index 32976aadede..ab7aa564477 100644
--- a/src/comp/middle/resolve.rs
+++ b/src/comp/middle/resolve.rs
@@ -886,8 +886,8 @@ fn found_view_item(&env e, @ast::view_item vi, namespace ns) ->
    option::t[def] {
     alt (vi.node) {
         case (ast::view_item_use(_, _, ?id)) {
-            auto crate_map = e.cstore.use_crate_map;
-            ret some(ast::def_mod(tup(crate_map.get(id), -1)));
+            auto cnum = cstore::get_use_stmt_cnum(e.cstore, id);
+            ret some(ast::def_mod(tup(cnum, -1)));
         }
         case (ast::view_item_import(_, _, ?id)) {
             ret lookup_import(e, local_def(id), ns);