Parsing routines for X-Force-TLS header....

net/base/force_tls_state.cc

 // Copyright (c) 2009 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.
 
 #include "net/base/force_tls_state.h"
 
 #include "base/logging.h"
+#include "base/string_tokenizer.h"
+#include "base/string_util.h"
 #include "googleurl/src/gurl.h"
 #include "net/base/registry_controlled_domain.h"
 
 namespace net {
 
 ForceTLSState::ForceTLSState() {
 }
 
 void ForceTLSState::DidReceiveHeader(const GURL& url,
                                      const std::string& value) {
   // TODO(abarth): Actually parse |value| once the spec settles down.
   EnableHost(url.host());
 }
 
 void ForceTLSState::EnableHost(const std::string& host) {
   // TODO(abarth): Canonicalize host.
   AutoLock lock(lock_);
   enabled_hosts_.insert(host);
 }
 
 bool ForceTLSState::IsEnabledForHost(const std::string& host) {
   // TODO(abarth): Canonicalize host.
   AutoLock lock(lock_);
   return enabled_hosts_.find(host) != enabled_hosts_.end();
 }
 
+// "X-Force-TLS" ":" "max-age" "=" delta-seconds *1INCLUDESUBDOMAINS

[wtc, 2009/06/01 17:59:19]

OK, so you have the header's definition here.  Would be nice
to move it (perhaps a version paraphrased in English) to the
header so that users of this class can understand this method
without reading the .cc file.

[abarth-chromium, 2009/06/02 02:24:05]

Ok......  The only reason this method is public is to make it unit testable. 
I'd rather wait until this settles down a bit before putting a lot of effort
into documenting it.

+// INCLUDESUBDOMAINS = [ " includeSubDomains" ]
+bool ForceTLSState::ParseHeader(const std::string& value,
+                                int* max_age,
+                                bool* include_subdomains) {
+  DCHECK(max_age);
+  DCHECK(include_subdomains);
+
+  int max_age_candidate;
+
+  enum ParserState {
+    START,
+    AFTER_MAX_AGE_LABEL,
+    AFTER_MAX_AGE_EQUALS,
+    AFTER_MAX_AGE,
+    AFTER_MAX_AGE_INCLUDE_SUB_DOMAINS_DELIMITER,
+    AFTER_INCLUDE_SUBDOMAINS,
+  } state = START;
+
+  StringTokenizer tokenizer(value, " =");
+  tokenizer.set_options(StringTokenizer::RETURN_DELIMS);
+  while (tokenizer.GetNext()) {
+    DCHECK(!tokenizer.token_is_delim() || tokenizer.token().length() == 1);
+    DCHECK(tokenizer.token_is_delim() || *tokenizer.token_begin() != ' ');
+    switch (state) {
+      case START:
+        if (*tokenizer.token_begin() == ' ')
+          continue;
+        if (!LowerCaseEqualsASCII(tokenizer.token(), "max-age"))
+          return false;
+        state = AFTER_MAX_AGE_LABEL;
+        break;
+
+      case AFTER_MAX_AGE_LABEL:
+        if (*tokenizer.token_begin() == ' ')
+          continue;
+        if (*tokenizer.token_begin() != '=')
+          return false;
+        DCHECK(tokenizer.token().length() ==  1);
+        state = AFTER_MAX_AGE_EQUALS;
+        break;
+
+      case AFTER_MAX_AGE_EQUALS:
+        if (*tokenizer.token_begin() == ' ')
+          continue;
+        if (!StringToInt(tokenizer.token(), &max_age_candidate))
+          return false;
+        if (max_age_candidate < 0)
+          return false;
+        state = AFTER_MAX_AGE;
+        break;
+
+      case AFTER_MAX_AGE:
+        if (*tokenizer.token_begin() != ' ')
+          return false;
+        state = AFTER_MAX_AGE_INCLUDE_SUB_DOMAINS_DELIMITER;
+        break;
+
+      case AFTER_MAX_AGE_INCLUDE_SUB_DOMAINS_DELIMITER:
+        if (*tokenizer.token_begin() == ' ')
+          continue;
+        if (!LowerCaseEqualsASCII(tokenizer.token(), "includesubdomains"))
+          return false;
+        state = AFTER_INCLUDE_SUBDOMAINS;
+        break;
+
+      case AFTER_INCLUDE_SUBDOMAINS:
+        if (*tokenizer.token_begin() != ' ')
+          return false;
+        break;
+
+      default:
+        NOTREACHED();
+    }
+  }
+
+  // We've consumed all the input.  Let's see what state we ended up in.
+  switch (state) {
+    case START:
+    case AFTER_MAX_AGE_LABEL:
+    case AFTER_MAX_AGE_EQUALS:
+      return false;
+    case AFTER_MAX_AGE:
+    case AFTER_MAX_AGE_INCLUDE_SUB_DOMAINS_DELIMITER:
+      *max_age = max_age_candidate;
+      *include_subdomains = false;
+      return true;
+    case AFTER_INCLUDE_SUBDOMAINS:
+      *max_age = max_age_candidate;
+      *include_subdomains = true;
+      return true;
+    default:
+      NOTREACHED();
+      return false;
+  }
+}
+
 }  // namespace