Improve error handling of the transport security state generator.

net/tools/transport_security_state_generator/trie/trie_writer.h

 // Copyright (c) 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef NET_TOOLS_TRANSPORT_SECURITY_STATE_GENERATOR_TRIE_TRIE_WRITER_H_
 #define NET_TOOLS_TRANSPORT_SECURITY_STATE_GENERATOR_TRIE_TRIE_WRITER_H_
 
 #include <string>
 #include <vector>
 
@@ skipping 21 matching lines @@
 
   TrieWriter(const HuffmanRepresentationTable& huffman_table,
              const NameIDMap& domain_ids_map,
              const NameIDMap& expect_ct_report_uri_map,
              const NameIDMap& expect_staple_report_uri_map,
              const NameIDMap& pinsets_map,
              HuffmanBuilder* huffman_builder);
   ~TrieWriter();
 
   // Constructs a trie containing all |entries|. The output is written to
-  // |buffer_|. Returns the position of the trie root.
-  uint32_t WriteEntries(const TransportSecurityStateEntries& entries);
+  // |buffer_| and |*position| is set to the position of the trie root. Returns
+  // true on success and false on failure.
+  bool WriteEntries(const TransportSecurityStateEntries& entries,
+                    uint32_t* position);
 
   // Returns the position |buffer_| is currently at. The returned value
   // represents the number of bits.
   uint32_t position() const;
 
   // Flushes |buffer_|.
   void Flush();
 
   // Returns the trie bytes. Call Flush() first to ensure the buffer is
   // complete.
   const std::vector<uint8_t>& bytes() const { return buffer_.bytes(); }
 
  private:
-  uint32_t WriteDispatchTables(ReversedEntries::iterator start,
-                               ReversedEntries::iterator end);
+  bool WriteDispatchTables(ReversedEntries::iterator start,
+                           ReversedEntries::iterator end,
+                           uint32_t* position);
 
   // Serializes |*entry| and writes it to |*writer|.
-  void WriteEntry(const TransportSecurityStateEntry* entry,
+  bool WriteEntry(const TransportSecurityStateEntry* entry,
                   TrieBitBuffer* writer);
 
   // Removes the first |length| characters from all entries between |start| and
   // |end|.
   void RemovePrefix(size_t length,
                     ReversedEntries::iterator start,
                     ReversedEntries::iterator end);
 
   // Searches for the longest common prefix for all entries between |start| and
   // |end|.
-  std::vector<uint8_t> LongestCommonPrefix(ReversedEntries::iterator start,
-                                           ReversedEntries::iterator end) const;
+  std::vector<uint8_t> LongestCommonPrefix(
+      ReversedEntries::const_iterator start,
+      ReversedEntries::const_iterator end) const;
 
   // Returns the reversed |hostname| as a vector of bytes. The reversed hostname
   // will be terminated by |kTerminalValue|.
   std::vector<uint8_t> ReverseName(const std::string& hostname) const;
 
   BitWriter buffer_;
   const HuffmanRepresentationTable& huffman_table_;
   const NameIDMap& domain_ids_map_;
   const NameIDMap& expect_ct_report_uri_map_;
   const NameIDMap& expect_staple_report_uri_map_;
   const NameIDMap& pinsets_map_;
   HuffmanBuilder* huffman_builder_;
 };
 
 }  // namespace transport_security_state
 
 }  // namespace net
 
 #endif  // NET_TOOLS_TRANSPORT_SECURITY_STATE_GENERATOR_TRIE_TRIE_WRITER_H_