ake string_util::WriteInto() DCHECK() that the supplied |length_with_null| > 1, meaning that the without-'\0' string is non-empty. This replaces the conditional code added recently that makes this case return NULL. It's easier to understand if it's simply an error to call WriteInto() in this case at all.

Add DCHECK()s or conditionals as appropriate to callers in order to ensure this assertion holds.

BUG=none
TEST=none
Review URL: http://codereview.chromium.org/8418034

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@112005 0039d316-1c4b-4281-b951-d872f2087c98

2 files changed, 8 insertions, 5 deletions

diff --git a/net/http/http_mac_signature.cc b/net/http/http_mac_signature.cc
index 93498ef..e445165 100644
--- a/net/http/http_mac_signature.cc
+++ b/net/http/http_mac_signature.cc
@@ -158,9 +158,12 @@ bool HttpMacSignature::GenerateMAC(const std::string& age,
 
   std::string signature;
   size_t length = hmac.DigestLength();
-  char* buffer = WriteInto(&signature, length);
-  if (!hmac.Sign(request, reinterpret_cast<unsigned char*>(buffer),
-                 length)) {
+  DCHECK_GT(length, 0u);
+  if (!hmac.Sign(request,
+          // We need the + 1 here not because the call will write a trailing \0,
+          // but so that signature.length() is correctly set to |length|.
+          reinterpret_cast<unsigned char*>(WriteInto(&signature, length + 1)),
+          length)) {
     NOTREACHED();
     return false;
   }
diff --git a/net/http/http_mac_signature_unittest.cc b/net/http/http_mac_signature_unittest.cc
index 74064dd..130ce39 100644
--- a/net/http/http_mac_signature_unittest.cc
+++ b/net/http/http_mac_signature_unittest.cc
@@ -59,7 +59,7 @@ TEST(HttpMacSignatureTest, GenerateHeaderString) {
   EXPECT_TRUE(signature.GenerateHeaderString(age, nonce, &header_string));
   EXPECT_EQ("MAC id=\"dfoi30j0qnf\", "
             "nonce=\"239034:mn4302j0n+32r2/f3r=\", "
-            "mac=\"GrkHtPKzB1m1dCHfa7OCWOw6EQ==\"",
+            "mac=\"GrkHtPKzB1m1dCHfa7OCWOw6Ecw=\"",
             header_string);
 }
 
@@ -104,6 +104,6 @@ TEST(HttpMacSignatureTest, GenerateMAC) {
 
   std::string mac;
   EXPECT_TRUE(signature.GenerateMAC(age, nonce, &mac));
-  EXPECT_EQ("GrkHtPKzB1m1dCHfa7OCWOw6EQ==", mac);
+  EXPECT_EQ("GrkHtPKzB1m1dCHfa7OCWOw6Ecw=", mac);
 }
 }