Elide long emails in the wrench and profile menus.

ui/base/text/text_elider.cc

 // Copyright (c) 2012 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.
 //
 // This file implements utility functions for eliding and formatting UI text.
 //
 // Note that several of the functions declared in text_elider.h are implemented
 // in this file using helper classes in the anonymous namespace.
 
 #include "ui/base/text/text_elider.h"
@@ skipping 17 matching lines @@
 #include "ui/gfx/font.h"
 #include "unicode/rbbi.h"
 #include "unicode/uloc.h"
 
 namespace ui {
 
 // U+2026 in utf8
 const char kEllipsis[] = "\xE2\x80\xA6";
 const char16 kForwardSlash = '/';
 
+const size_t kMaxProfileUsernameLength = 20;
+
 namespace {
 
 // Helper class to split + elide text, while respecting UTF16 surrogate pairs.
 class StringSlicer {
  public:
   StringSlicer(const string16& text,
                const string16& ellipsis,
                bool elide_in_middle)
       : text_(text),
         ellipsis_(ellipsis),
@@ skipping 94 matching lines @@
     if (available_pixel_width >= font.GetStringWidth(elided_path))
       return ElideText(elided_path + url_query,
                        font, available_pixel_width, ELIDE_AT_END);
   }
 
   return string16();
 }
 
 }  // namespace
 
+// Elides only the username portion of the email, if possible, so that the
+// overall email is at most max_email_length characters (e.g.
+// longusername@host.com --> longuser...@host.com for max_email_length == 20).
+// If the domain name by itself already has more characters than available,
+// we elide the domain name in the middle so that only max_email_length / 2
+// characters remain. We then proceed with the regular eliding described above.
+// In any scenario: the string returned will never be longer than
+// max_email_length including the inserted ellipses; and the elided strings
+// will have at least one character remaining on either side of the '@'(other
+// than the ellipsis-es).
+// This function assumes max_email_length is >= 5.

[Alexei Svitkine (slow), 2012/02/28 15:46:22]

It is sufficient to only include the comment in the header declaration of the
function.

[gab, 2012/02/28 19:20:11]

Ok, was mimicking ElideUrl which has the comment in both places (should I
refactor that at the same time?)

On 2012/02/28 15:46:22, Alexei Svitkine wrote:

+string16 ElideEmail(const string16& email, size_t max_email_length) {
+  DCHECK_GE(max_email_length, size_t(5));
+
+  if (email.length() <= max_email_length)
+    return email;
+
+  std::vector<string16> email_split;
+  base::SplitString(email, '@', &email_split);
+  DCHECK_EQ(email_split.size(), size_t(2));

[Alexei Svitkine (slow), 2012/02/28 15:46:22]

We don't use constructor-style casts in the Chromium codebase. Generally, this
would be static_cast<size_t>(2), but in this case you can use 2U to indicate
that it's unsigned.

+  string16& username = email_split.front();
+  string16& domain = email_split.back();

[Alexei Svitkine (slow), 2012/02/28 15:46:22]

Non-const references are discouraged - remove the &'s here.

[gab, 2012/02/28 19:20:11]

Ok, but this will force an implicit copy of the string which is unnecessary, are
we ok with that?

On 2012/02/28 15:46:22, Alexei Svitkine wrote:

+
+  const string16 kEllipsisUTF16 = UTF8ToUTF16(kEllipsis);
+  const size_t kEllipsisLength = kEllipsisUTF16.length();
+
+  // Reserve characters for each of: username ellipsis, @ sign, and at least
+  // one character remaining in the username.
+  const size_t kAvailableDomainChars = max_email_length - kEllipsisLength - 2;

[Alexei Svitkine (slow), 2012/02/28 15:46:22]

Rename to |available_domain_chars| since this is a computed constant that
depends on function parameters.

+  if (domain.length() > kAvailableDomainChars) {
+    StringSlicer slicer(domain, kEllipsisUTF16, true);
+    const size_t n = max_email_length / 2 - kEllipsisLength;

[Alexei Svitkine (slow), 2012/02/28 15:46:22]

Nit: Rename |n| to |length|. Same thing in the block below.

+    domain = slicer.CutString(n, true);
+  }
+
+  const size_t kFinalDomainLength = domain.length();

[Alexei Svitkine (slow), 2012/02/28 15:46:22]

Same comment as for kAvailableDomainChars above. Although, in this case, I
suggest just using |domain.length()| directly below, since it's actually
shorter.

[gab, 2012/02/28 19:20:11]

|domain.length()| is shorter, but is a function (hence why I made a variable) as
the value is potentially needed twice; I'll only rename it, let me know if you
want me to proceed otherwise.

On 2012/02/28 15:46:22, Alexei Svitkine wrote:

+  if (username.length() + kFinalDomainLength + 1 > max_email_length) {
+    StringSlicer slicer(username, kEllipsisUTF16, false);
+    const size_t n = max_email_length - kFinalDomainLength -
+                     kEllipsisLength - 1;
+    username = slicer.CutString(n, true);
+  }
+
+  return username + ASCIIToUTF16("@") + domain;
+}
+
 // This function takes a GURL object and elides it. It returns a string
 // which composed of parts from subdomain, domain, path, filename and query.
 // A "..." is added automatically at the end if the elided string is bigger
 // than the available pixel width. For available pixel width = 0, a formatted,
 // but un-elided, string is returned.
 //
 // TODO(pkasting): http://crbug.com/77883 This whole function gets
 // kerning/ligatures/etc. issues potentially wrong by assuming that the width of
 // a rendered string is always the sum of the widths of its substrings.  Also I
 // suspect it could be made simpler.
@@ skipping 899 matching lines @@
       index = char_iterator.getIndex();
     } else {
       // String has leading whitespace, return the elide string.
       return kElideString;
     }
   }
   return string.substr(0, index) + kElideString;
 }
 
 }  // namespace ui