From 9595dfa2dccef73009cf71078627d5ef7ed3e514 Mon Sep 17 00:00:00 2001
From: Joshua Haberman <joshua@reverberate.org>
Date: Wed, 24 Jun 2009 17:44:43 -0700
Subject: Fleshed out upb_context some.

---
 upb_context.h | 84 ++++++++++++++++++++++++++++++++++++++++++++++++++---------
 1 file changed, 72 insertions(+), 12 deletions(-)

(limited to 'upb_context.h')

diff --git a/upb_context.h b/upb_context.h
index f2bb1df..bf8e3b6 100644
--- a/upb_context.h
+++ b/upb_context.h
@@ -1,16 +1,16 @@
 /*
  * upb - a minimalist implementation of protocol buffers.
  *
- * A context represents a namespace of proto definitions, sort of like
- * an interpreter's symbol table.  It is empty when first constructed.
- * Clients add definitions to the context by supplying serialized
- * descriptors (as defined in descriptor.proto).
+ * A context represents a namespace of proto definitions, sort of like an
+ * interpreter's symbol table.  It is mostly empty when first constructed.
+ * Clients add definitions to the context by supplying unserialized or
+ * serialized descriptors (as defined in descriptor.proto).
  *
- * Copyright (c) 2008 Joshua Haberman.  See LICENSE for details.
+ * Copyright (c) 2009 Joshua Haberman.  See LICENSE for details.
  */
 
-#ifndef UPB_PARSE_H_
-#define UPB_PARSE_H_
+#ifndef UPB_CONTEXT_H_
+#define UPB_CONTEXT_H_
 
 #include "upb.h"
 #include "upb_table.h"
@@ -19,8 +19,6 @@
 extern "C" {
 #endif
 
-/* High-level parsing interface. **********************************************/
-
 enum upb_symbol_type {
   UPB_SYM_MESSAGE,
   UPB_SYM_ENUM,
@@ -36,13 +34,75 @@ struct upb_symtab_entry {
     struct upb_enum *_enum;
     struct upb_svc *svc;
   } p;
-}
+};
 
 struct upb_context {
-  upb_strtable *symtab;
+  struct upb_strtable symtab;
+};
+
+/* Initializes and frees a upb_context, respectively.  Newly initialized
+ * contexts will always have the types in descriptor.proto defined. */
+void upb_context_init(struct upb_context *c);
+void upb_context_free(struct upb_context *c);
+
+/* Looking up symbols. ********************************************************/
+
+/* Nested type names are separated by periods. */
+#define UPB_CONTEXT_SEPARATOR '.'
+#define UPB_SYM_MAX_LENGTH 256
+
+/* Resolves the given symbol using the rules described in descriptor.proto,
+ * namely:
+ *
+ *    If the name starts with a '.', it is fully-qualified.  Otherwise, C++-like
+ *    scoping rules are used to find the type (i.e. first the nested types
+ *    within this message are searched, then within the parent, on up to the
+ *    root namespace).
+ *
+ * Returns NULL if the symbol has not been defined. */
+struct upb_symtab_entry *upb_context_resolve(struct upb_context *c,
+                                             struct upb_string *base,
+                                             struct upb_string *symbol);
+
+/* Find an entry in the symbol table with this exact name.  Returns NULL if no
+ * such symbol name exists. */
+struct upb_symtab_entry *upb_context_lookup(struct upb_context *c,
+                                            struct upb_string *symbol);
+
+/* Adding symbols. ************************************************************/
+
+/* Enum controlling what happens if a symbol is redefined. */
+enum upb_onredef {
+  UPB_ONREDEF_REPLACE, /* Replace existing definition (must be same type). */
+  UPB_ONREDEF_KEEP,    /* Keep existing definition, ignore new one. */
+  UPB_ONREDEF_ERROR    /* Error on redefinition. */
 };
 
-struct upb_symtab_entry *upb_context_findsym(struct upb_context *c, struct upb_string *s);
+/* Adds the definitions in the given file descriptor to this context.  All
+ * types that are referenced from fd must have previously been defined (or be
+ * defined in fd).  onredef controls the behavior in the case that fd attempts
+ * to define a type that is already defined.
+ *
+ * Caller retains ownership of fd, but the context will contain references to
+ * it, so it must outlive the context. */
+bool upb_context_addfd(struct upb_context *c,
+                       google_protobuf_FileDescriptorProto *fd,
+                       int onredef);
+
+/* Adds the serialized FileDescriptorSet proto contained in fdss to the context,
+ * and adds symbol table entries for all the objects defined therein.  onredef
+ * controls the behavior in the case the fds attempts to define a type that is
+ * already defined.
+ *
+ * Returns true if the protobuf in fds was parsed successfully and all
+ * references were successfully resolved.  If false is returned, the context is
+ * unmodified.  */
+bool upb_context_parsefds(struct upb_context *c, struct upb_string *fds,
+                          int onredef);
+
+/* Like the previous, but for a single FileDescriptorProto instead of a set. */
+bool upb_context_parsefd(struct upb_context *c, struct upb_string *fds,
+                         int onredef);
 
 #ifdef __cplusplus
 }  /* extern "C" */
-- 
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