dom/base/ViewportMetaData.cpp

   1 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* vim: set ts=8 sts=2 et sw=2 tw=80: */
   3 /* This Source Code Form is subject to the terms of the Mozilla Public
   4  * License, v. 2.0. If a copy of the MPL was not distributed with this
   5  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   6
   7 #include "nsContentUtils.h"
   8 #include "nsCRT.h"
   9 #include "ViewportMetaData.h"
  10
  11 using namespace mozilla;
  12 using namespace mozilla::dom;
  13
  14 /*
  15  * Helper function for ViewportMetaData::ProcessViewportInfo.
  16  *
  17  * Handles a single key=value pair. If it corresponds to a valid viewport
  18  * attribute, add it to the document header data. No validation is done on the
  19  * value itself (this is done at display time).
  20  */
  21 static void ProcessViewportToken(ViewportMetaData& aData,
  22                                  const nsAString& token) {
  23   /* Iterators. */
  24   nsAString::const_iterator tip, tail, end;
  25   token.BeginReading(tip);
  26   tail = tip;
  27   token.EndReading(end);
  28
  29   /* Move tip to the '='. */
  30   while ((tip != end) && (*tip != '=')) {
  31     ++tip;
  32   }
  33
  34   /* If we didn't find an '=', punt. */
  35   if (tip == end) {
  36     return;
  37   }
  38
  39   /* Extract the key and value. */
  40   const nsAString& key = nsContentUtils::TrimWhitespace<nsCRT::IsAsciiSpace>(
  41       Substring(tail, tip), true);
  42   const nsAString& value = nsContentUtils::TrimWhitespace<nsCRT::IsAsciiSpace>(
  43       Substring(++tip, end), true);
  44
  45   /* Check for known keys. If we find a match, insert the appropriate
  46    * information into the document header. */
  47   RefPtr<nsAtom> key_atom = NS_Atomize(key);
  48   if (key_atom == nsGkAtoms::height) {
  49     aData.mHeight.Assign(value);
  50   } else if (key_atom == nsGkAtoms::width) {
  51     aData.mWidth.Assign(value);
  52   } else if (key_atom == nsGkAtoms::initial_scale) {
  53     aData.mInitialScale.Assign(value);
  54   } else if (key_atom == nsGkAtoms::minimum_scale) {
  55     aData.mMinimumScale.Assign(value);
  56   } else if (key_atom == nsGkAtoms::maximum_scale) {
  57     aData.mMaximumScale.Assign(value);
  58   } else if (key_atom == nsGkAtoms::user_scalable) {
  59     aData.mUserScalable.Assign(value);
  60   } else if (key_atom == nsGkAtoms::viewport_fit) {
  61     aData.mViewportFit.Assign(value);
  62   }
  63 }
  64
  65 #define IS_SEPARATOR(c)                                             \
  66   (((c) == '=') || ((c) == ',') || ((c) == ';') || ((c) == '\t') || \
  67    ((c) == '\n') || ((c) == '\r'))
  68
  69 ViewportMetaData::ViewportMetaData(const nsAString& aViewportInfo) {
  70   /* Iterators. */
  71   nsAString::const_iterator tip, tail, end;
  72   aViewportInfo.BeginReading(tip);
  73   tail = tip;
  74   aViewportInfo.EndReading(end);
  75
  76   /* Read the tip to the first non-separator character. */
  77   while ((tip != end) && (IS_SEPARATOR(*tip) || nsCRT::IsAsciiSpace(*tip))) {
  78     ++tip;
  79   }
  80
  81   /* Read through and find tokens separated by separators. */
  82   while (tip != end) {
  83     /* Synchronize tip and tail. */
  84     tail = tip;
  85
  86     /* Advance tip past non-separator characters. */
  87     while ((tip != end) && !IS_SEPARATOR(*tip)) {
  88       ++tip;
  89     }
  90
  91     /* Allow white spaces that surround the '=' character */
  92     if ((tip != end) && (*tip == '=')) {
  93       ++tip;
  94
  95       while ((tip != end) && nsCRT::IsAsciiSpace(*tip)) {
  96         ++tip;
  97       }
  98
  99       while ((tip != end) &&
 100              !(IS_SEPARATOR(*tip) || nsCRT::IsAsciiSpace(*tip))) {
 101         ++tip;
 102       }
 103     }
 104
 105     /* Our token consists of the characters between tail and tip. */
 106     ProcessViewportToken(*this, Substring(tail, tip));
 107
 108     /* Skip separators. */
 109     while ((tip != end) && (IS_SEPARATOR(*tip) || nsCRT::IsAsciiSpace(*tip))) {
 110       ++tip;
 111     }
 112   }
 113 }
 114
 115 #undef IS_SEPARATOR