Adding support for Reset in StringTokenizerT and HttpHeadersIterator.

TEST=Run HeadersIterator_Reset and the Reset test for StringTokenizer
BUG=none

Review URL: http://codereview.chromium.org/276067

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@29330 0039d316-1c4b-4281-b951-d872f2087c98

base/string_tokenizer.h

@@ -141,6 +141,11 @@ class StringTokenizerT {
     return true;
   }
 
+  // Start iterating through tokens from the beginning of the string.
+  void Reset() {
+    token_end_ = start_pos_;
+  }
+
   // Returns true if token is a delimiter.  When the tokenizer is constructed
   // with the RETURN_DELIMS option, this method can be used to check if the
   // returned token is actually a delimiter.
@@ -156,6 +161,7 @@ class StringTokenizerT {
   void Init(const_iterator string_begin,
             const_iterator string_end,
             const str& delims) {
+    start_pos_ = string_begin;
     token_end_ = string_begin;
     end_ = string_end;
     delims_ = delims;
@@ -195,6 +201,7 @@ class StringTokenizerT {
     return true;
   }
 
+  const_iterator start_pos_;
   const_iterator token_begin_;
   const_iterator token_end_;
   const_iterator end_;

base/string_tokenizer_unittest.cc

@@ -30,6 +30,28 @@ TEST(StringTokenizerTest, Simple) {
   EXPECT_FALSE(t.GetNext());
 }
 
+TEST(StringTokenizerTest, Reset) {
+  string input = "this is a test";
+  StringTokenizer t(input, " ");
+
+  for (int i = 0; i < 2; ++i) {
+    EXPECT_TRUE(t.GetNext());
+    EXPECT_EQ(string("this"), t.token());
+
+    EXPECT_TRUE(t.GetNext());
+    EXPECT_EQ(string("is"), t.token());
+
+    EXPECT_TRUE(t.GetNext());
+    EXPECT_EQ(string("a"), t.token());
+
+    EXPECT_TRUE(t.GetNext());
+    EXPECT_EQ(string("test"), t.token());
+
+    EXPECT_FALSE(t.GetNext());
+    t.Reset();
+  }
+}
+
 TEST(StringTokenizerTest, RetDelims) {
   string input = "this is a test";
   StringTokenizer t(input, " ");

net/http/http_util.h

@@ -167,6 +167,10 @@ class HttpUtil {
     // current position will be at the end of the headers.
     bool AdvanceTo(const char* lowercase_name);
 
+    void Reset() {
+      lines_.Reset();
+    }
+
     std::string::const_iterator name_begin() const {
       return name_begin_;
     }

net/http/http_util_unittest.cc

@@ -105,6 +105,19 @@ TEST(HttpUtilTest, HeadersIterator_AdvanceTo) {
   EXPECT_FALSE(it.GetNext());  // should be at end of headers
 }
 
+TEST(HttpUtilTest, HeadersIterator_Reset) {
+  std::string headers = "foo: 1\r\n: 2\r\n3\r\nbar: 4";
+  HttpUtil::HeadersIterator it(headers.begin(), headers.end(), "\r\n");
+  // Search past "foo".
+  EXPECT_TRUE(it.AdvanceTo("bar"));
+  // Now try advancing to "foo".  This time it should fail since the iterator
+  // position is past it.
+  EXPECT_FALSE(it.AdvanceTo("foo"));
+  it.Reset();
+  // Now that we reset the iterator position, we should find 'foo'
+  EXPECT_TRUE(it.AdvanceTo("foo"));
+}
+
 TEST(HttpUtilTest, ValuesIterator) {
   std::string values = " must-revalidate,   no-cache=\"foo, bar\"\t, private ";