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 131 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
 
-// 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.
-//
+string16 ElideEmail(const string16& email,
+                    const gfx::Font& font,
+                    int available_pixel_width) {
+  if (font.GetStringWidth(email) <= available_pixel_width)
+    return email;
+
+  // Split the email into its local-part (username) and domain-part. The email
+  // spec technically allows for @ symbols in the local-part (username) of the
+  // email under some special requirements. It is guaranteed that there is no @
+  // symbol in the domain part of the email however so splitting at the last @
+  // symbol is safe.
+  const size_t split_index = email.find_last_of('@');
+  DCHECK_NE(split_index, string16::npos);
+  string16 username = email.substr(0, split_index);
+  string16 domain = email.substr(split_index + 1);
+  DCHECK(!username.empty());
+  DCHECK(!domain.empty());
+
+  const string16 kEllipsisUTF16 = UTF8ToUTF16(kEllipsis);
+
+  // Subtract the @ symbol from the available width as it is mandatory.
+  const string16 kAtSignUTF16 = ASCIIToUTF16("@");
+  available_pixel_width -= font.GetStringWidth(kAtSignUTF16);
+
+  // Check whether eliding the domain is necessary: if eliding the username
+  // is sufficient, the domain will not be elided.
+  const int full_username_width = font.GetStringWidth(username);
+  const int available_domain_width =
+      available_pixel_width -
+      std::min(full_username_width,
+               font.GetStringWidth(username.substr(0, 1) + kEllipsisUTF16));
+  if (font.GetStringWidth(domain) > available_domain_width) {
+    // Elide the domain so that it only takes half of the available width.
+    // Should the username not need all the width available in its half, the
+    // domain will occupy the leftover width.
+    // If |desired_domain_width| is greater than |available_domain_width|: the
+    // minimal username elision allowed by the specifications will not fit; thus
+    // |desired_domain_width| must be <= |available_domain_width| at all cost.
+    const int desired_domain_width =
+        std::min(available_domain_width,
+                 std::max(available_pixel_width - full_username_width,
+                          available_pixel_width / 2));
+    domain = ElideText(domain, font, desired_domain_width, ELIDE_IN_MIDDLE);
+    // Failing to elide the domain such that at least one character remains
+    // (other than the ellipsis itself) remains: return a single ellipsis.
+    if (domain.length() <= 1U)
+      return kEllipsisUTF16;
+  }
+
+  // Fit the username in the remaining width (at this point the elided username
+  // is guaranteed to fit with at least one character remaining given all the
+  // precautions taken earlier).
+  username = ElideText(username,
+                       font,
+                       available_pixel_width - font.GetStringWidth(domain),
+                       ELIDE_AT_END);
+
+  return username + kAtSignUTF16 + domain;
+}
+
 // 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.
 string16 ElideUrl(const GURL& url,
                   const gfx::Font& font,
                   int available_pixel_width,
                   const std::string& languages) {
   // Get a formatted string and corresponding parsing of the url.
   url_parse::Parsed parsed;
@@ skipping 218 matching lines @@
     return base::i18n::GetDisplayStringInLTRDirectionality(elided_name);
   }
 
   int available_root_width = available_pixel_width - ext_width;
   string16 elided_name =
       ElideText(rootname, font, available_root_width, ELIDE_AT_END);
   elided_name += extension;
   return base::i18n::GetDisplayStringInLTRDirectionality(elided_name);
 }
 
-// This function adds an ellipsis at the end of the text if the text
-// does not fit the given pixel width.
 string16 ElideText(const string16& text,
                    const gfx::Font& font,
                    int available_pixel_width,
                    ElideBehavior elide_behavior) {
   if (text.empty())
     return text;
 
   const string16 kEllipsisUTF16 = UTF8ToUTF16(kEllipsis);
 
   const int current_text_pixel_width = font.GetStringWidth(text);
@@ skipping 653 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