Support IDNA 2008

url/url_canon_icu.cc

Index: url/url_canon_icu.cc
===================================================================
--- url/url_canon_icu.cc	(revision 223643)
+++ url/url_canon_icu.cc	(working copy)
@@ -7,6 +7,7 @@
 #include <stdlib.h>
 #include <string.h>
 
+#include "base/lazy_instance.h"
 #include "base/logging.h"
 #include "third_party/icu/source/common/unicode/ucnv.h"
 #include "third_party/icu/source/common/unicode/ucnv_cb.h"
@@ -71,6 +72,26 @@
   const void* old_context_;
 };
 
+struct uidna_wrapper {
+  uidna_wrapper() {
+    UErrorCode err = U_ZERO_ERROR;
+    // This is the option closest to what we had in the past with IDNA 2003
+    // API and matches what IE 10 does except for BiDi check.
+    // IDNA 2003 always checks BiDi. We used to allow unassigned code
+    // points. However, with our Unicode DB pretty up to date, we'd not
+    // need to turn this on.
+    // We didn't use STD3 rules and we continue not to.
+    // TODO(jungshik) : Change options as different parties (browsers,
+    // registrars, search engines) converge toward a consensus.
+    int32_t options = UIDNA_CHECK_BIDI;
+    value = uidna_openUTS46(options, &err);
+    if (U_FAILURE(err))
+      value = NULL;
+  }
+
+  UIDNA* value;
+};
+
 }  // namespace
 
 ICUCharsetConverter::ICUCharsetConverter(UConverter* converter)
@@ -107,6 +128,9 @@
   } while (true);
 }
 
+static base::LazyInstance<uidna_wrapper>::Leaky
+    g_uidna = LAZY_INSTANCE_INITIALIZER;
+
 // Converts the Unicode input representing a hostname to ASCII using IDN rules.
 // The output must be ASCII, but is represented as wide characters.
 //
@@ -116,25 +140,33 @@
 // the length of the output will be set to the length of the new host name.
 //
 // On error, this will return false. The output in this case is undefined.
+// TODO(jungshik): use UTF-8/ASCII version of nameToASCII.
+// Change the function signature and callers accordingly to avoid unnecessary
+// conversions in our code. In addition, consider using icu::IDNA's UTF-8/ASCII
+// version with StringByteSink. That way, we can avoid C wrappers and additional
+// string conversion.
 bool IDNToASCII(const base::char16* src, int src_len, CanonOutputW* output) {
   DCHECK(output->length() == 0);  // Output buffer is assumed empty.
+
+  UIDNA* uidna = g_uidna.Get().value;
+  DCHECK(uidna != NULL);

[brettw, 2013/09/19 17:44:45]

Under what cases might we get an error that would result in this being null? I
just want to make sure we don't actually need to handle the error and fall back
on something.

[jungshik at Google, 2013/09/19 19:16:16]

I don't think it'll fail unless we can't get access the ICU data file for an
unforseeable reason. Even if that happens,  uidna_nameToASCII (called below)
would bail out immediately with 'invalid argument error) and U_SUCCESS(err)
would be false and we'd return false. 

   while (true) {
-    // Use ALLOW_UNASSIGNED to be more tolerant of hostnames that violate
-    // the spec (which do exist). This does not present any risk and is a
-    // little more future proof.
     UErrorCode err = U_ZERO_ERROR;
-    int num_converted = uidna_IDNToASCII(src, src_len, output->data(),
-                                         output->capacity(),
-                                         UIDNA_ALLOW_UNASSIGNED, NULL, &err);
-    if (err == U_ZERO_ERROR) {
-      output->set_length(num_converted);
+    UIDNAInfo info = UIDNA_INFO_INITIALIZER;
+    int output_length = uidna_nameToASCII(uidna, src, src_len, output->data(),
+                                          output->capacity(), &info, &err);
+    if (U_SUCCESS(err) && info.errors == 0) {
+      output->set_length(output_length);
       return true;
     }
-    if (err != U_BUFFER_OVERFLOW_ERROR)
+
+    // TODO(jungshik): Look at info.errors to handle them case-by-case basis
+    // if necessary.
+    if (err != U_BUFFER_OVERFLOW_ERROR || info.errors != 0)
       return false;  // Unknown error, give up.
 
     // Not enough room in our buffer, expand.
-    output->Resize(output->capacity() * 2);
+    output->Resize(output_length);
   }
 }