make it possible to merge PGF files in the compiler

src/runtime/c/pgf/pgf.cxx

@@ -213,6 +213,33 @@ PgfDB *pgf_new_ngf(PgfText *abstract_name,
     return NULL;
 }
 
+PGF_API
+void pgf_merge_pgf(PgfDB *db, PgfRevision revision,
+                   const char* fpath,
+                   PgfExn* err)
+{
+    FILE *in = NULL;
+
+    PGF_API_BEGIN {
+        in = fopen(fpath, "rb");
+        if (!in) {
+            throw pgf_systemerror(errno, fpath);
+        }
+
+        {
+            DB_scope scope(db, WRITER_SCOPE);
+            ref<PgfPGF> pgf = PgfDB::revision2pgf(revision);
+
+            PgfReader rdr(in);
+            rdr.merge_pgf(pgf);
+        }
+    } PGF_API_END
+
+end:
+    if (in != NULL)
+        fclose(in);
+}
+
 PGF_API
 void pgf_write_pgf(const char* fpath,
                    PgfDB *db, PgfRevision revision,

src/runtime/c/pgf/pgf.h

@@ -257,6 +257,11 @@ PgfDB *pgf_new_ngf(PgfText *abstract_name,
                    PgfRevision *revision,
                    PgfExn* err);
 
+PGF_API
+void pgf_merge_pgf(PgfDB *db, PgfRevision revision,
+                   const char* fpath,
+                   PgfExn* err);
+
 PGF_API_DECL
 void pgf_write_pgf(const char* fpath,
                    PgfDB *db, PgfRevision revision,

src/runtime/c/pgf/reader.cxx

@@ -169,6 +169,16 @@ Namespace<V> PgfReader::read_namespace(ref<V> (PgfReader::*read_value)())
     return read_namespace(read_value, len);
 }
 
+template<class V>
+void PgfReader::merge_namespace(ref<V> (PgfReader::*read_value)())
+{
+    size_t len = read_len();
+    for (size_t i = 0; i < len; i++) {
+        ref<V> value = (this->*read_value)();
+        V::release(value);
+    }
+}
+
 template <class C, class V>
 ref<C> PgfReader::read_vector(Vector<V> C::* field, void (PgfReader::*read_value)(ref<V> val))
 {
@@ -371,6 +381,16 @@ void PgfReader::read_abstract(ref<PgfAbstr> abstract)
     abstract->cats = read_namespace<PgfAbsCat>(&PgfReader::read_abscat);
 }
 
+void PgfReader::merge_abstract(ref<PgfAbstr> abstract)
+{
+    this->abstract = abstract;
+
+    read_name(); // ?
+	merge_namespace<PgfFlag>(&PgfReader::read_flag); // ?
+    merge_namespace<PgfAbsFun>(&PgfReader::read_absfun); // ?
+    merge_namespace<PgfAbsCat>(&PgfReader::read_abscat); // ?
+}
+
 ref<PgfLParam> PgfReader::read_lparam()
 {
     size_t i0 = read_int();
@@ -597,3 +617,27 @@ ref<PgfPGF> PgfReader::read_pgf()
 
     return pgf;
 }
+
+void PgfReader::merge_pgf(ref<PgfPGF> pgf)
+{
+    uint16_t major_version = read_u16be();
+    uint16_t minor_version = read_u16be();
+
+    if (pgf->major_version != PGF_MAJOR_VERSION ||
+        pgf->minor_version != PGF_MINOR_VERSION) {
+        throw pgf_error("Unsupported format version");
+    }
+
+    merge_namespace<PgfFlag>(&PgfReader::read_flag); // ??
+
+    merge_abstract(ref<PgfAbstr>::from_ptr(&pgf->abstract));
+
+    size_t len = read_len();
+    for (size_t i = 0; i < len; i++) {
+        ref<PgfConcr> concr = PgfReader::read_concrete();
+        Namespace<PgfConcr> concrs =
+            namespace_insert(pgf->concretes, concr);
+        namespace_release(pgf->concretes);
+        pgf->concretes = concrs;
+    }
+}

src/runtime/c/pgf/reader.h

@@ -44,6 +44,9 @@ public:
     template<class V>
     Namespace<V> read_namespace(ref<V> (PgfReader::*read_value)());
 
+    template<class V>
+    void merge_namespace(ref<V> (PgfReader::*read_value)());
+
     template <class C, class V>
     ref<C> read_vector(Vector<V> C::* field, void (PgfReader::*read_value)(ref<V> val));
 
@@ -62,6 +65,7 @@ public:
     ref<PgfAbsFun> read_absfun();
     ref<PgfAbsCat> read_abscat();
     void read_abstract(ref<PgfAbstr> abstract);
+    void merge_abstract(ref<PgfAbstr> abstract);
 
     ref<PgfConcrLincat> read_lincat();
     ref<PgfLParam> read_lparam();
@@ -75,6 +79,7 @@ public:
     ref<PgfConcr> read_concrete();
 
     ref<PgfPGF> read_pgf();
+    void merge_pgf(ref<PgfPGF> pgf);
 
 private:
     FILE *in;