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/*
* upb - a minimalist implementation of protocol buffers.
*
* Copyright (c) 2009 Joshua Haberman. See LICENSE for details.
*/
#include <assert.h>
#include <stdlib.h>
#include <string.h>
#include "descriptor.h"
#include "upb_context.h"
int memrchr(char *data, char c, size_t len)
{
int off = len-1;
while(off > 0 && data[off] != c) --off;
return off;
}
void upb_context_init(struct upb_context *c)
{
upb_strtable_init(&c->symtab, 16, sizeof(struct upb_symtab_entry));
/* Add all the types in descriptor.proto so we can parse descriptors. */
if(!upb_context_addfd(c, &google_protobuf_filedescriptor, UPB_ONREDEF_ERROR))
assert(false);
}
void upb_context_free(struct upb_context *c)
{
upb_strtable_free(&c->symtab);
}
struct upb_symtab_entry *upb_context_lookup(struct upb_context *c,
struct upb_string *symbol)
{
return upb_strtable_lookup(&c->symtab, symbol);
}
struct upb_symtab_entry *upb_context_resolve(struct upb_context *c,
struct upb_string *base,
struct upb_string *symbol)
{
if(base->byte_len + symbol->byte_len + 1 >= UPB_SYM_MAX_LENGTH ||
symbol->byte_len == 0) return NULL;
if(symbol->data[0] == UPB_CONTEXT_SEPARATOR) {
/* Symbols starting with '.' are absolute, so we do a single lookup. */
struct upb_string sym_str = {.data = symbol->data+1,
.byte_len = symbol->byte_len-1};
return upb_context_lookup(c, &sym_str);
} else {
/* Remove components from base until we find an entry or run out. */
char sym[UPB_SYM_MAX_LENGTH+1];
struct upb_string sym_str = {.data = sym};
int baselen = base->byte_len;
while(1) {
/* sym_str = base[0...base_len] + UPB_CONTEXT_SEPARATOR + symbol */
memcpy(sym, base->data, baselen);
sym[baselen] = UPB_CONTEXT_SEPARATOR;
memcpy(sym + baselen + 1, symbol->data, symbol->byte_len);
sym_str.byte_len = baselen + symbol->byte_len + 1;
struct upb_symtab_entry *e = upb_context_lookup(c, &sym_str);
if (e) return e;
else if(baselen == 0) return NULL; /* No more scopes to try. */
baselen = memrchr(base->data, UPB_CONTEXT_SEPARATOR, baselen);
}
}
}
bool upb_context_addfd(struct upb_context *c,
google_protobuf_FileDescriptorProto *fd,
int onredef)
{
/* TODO: properly handle redefinitions and unresolvable symbols. */
if(fd->set_flags.has.message_type) {
for(unsigned int i = 0; i < fd->message_type->len; i++) {
struct google_protobuf_DescriptorProto *d = fd->message_type->elements[i];
if(!d->set_flags.has.name) return false;
struct upb_symtab_entry e;
e.e.key = *d->name;
e.type = UPB_SYM_MESSAGE;
e.p.msg = malloc(sizeof(*e.p.msg));
upb_msg_init(e.p.msg, d);
upb_strtable_insert(&c->symtab, &e.e);
}
}
/* TODO: handle enums, extensions, and services. */
return true;
}
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