Initial import of the Chrome Frame codebase. Integration in chrome.gyp coming...

chrome_frame/html_utils.cc

+// Copyright (c) 2009 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.
+//
+#include "chrome_frame/html_utils.h"
+
+#include "base/string_util.h"
+#include "base/string_tokenizer.h"
+
+const wchar_t* kQuotes = L"\"'";
+
+HTMLScanner::StringRange::StringRange() {
+}
+
+HTMLScanner::StringRange::StringRange(StrPos start, StrPos end)
+    : start_(start), end_(end) {
+}
+
+bool HTMLScanner::StringRange::LowerCaseEqualsASCII(const char* other) const {
+  return ::LowerCaseEqualsASCII(start_, end_, other);
+}
+
+bool HTMLScanner::StringRange::Equals(const wchar_t* other) const {
+  int ret = wcsncmp(&start_[0], other, end_ - start_);
+  if (ret == 0)
+    ret = (other[end_ - start_] == L'\0') ? 0 : -1;
+  return ret == 0;
+}
+
+std::wstring HTMLScanner::StringRange::Copy() const {
+  return std::wstring(start_, end_);
+}
+
+bool HTMLScanner::StringRange::GetTagName(std::wstring* tag_name) const {
+  if (*start_ != L'<') {
+    LOG(ERROR) << "Badly formatted tag found";
+    return false;
+  }
+
+  StrPos name_start = start_;
+  name_start++;
+  while (name_start < end_ && IsWhitespace(*name_start))
+    name_start++;
+
+  if (name_start >= end_) {
+    // We seem to have a degenerate tag (i.e. <   >). Return false here.
+    return false;
+  }
+
+  StrPos name_end = name_start + 1;
+  while (name_end < end_ && !IsWhitespace(*name_end))
+    name_end++;
+
+  if (name_end > end_) {
+    // This looks like an improperly formatted tab ('<foo'). Return false here.
+    return false;
+  }
+
+  tag_name->assign(name_start, name_end);
+  return true;
+}
+
+
+bool HTMLScanner::StringRange::GetTagAttribute(const wchar_t* attribute_name,
+    StringRange* attribute_value) const {
+  if (NULL == attribute_name || NULL == attribute_value) {
+    NOTREACHED();
+    return false;
+  }
+
+  // Use this so we can use the convenience method LowerCaseEqualsASCII()
+  // from string_util.h.
+  std::string search_name_ascii(WideToASCII(attribute_name));
+
+  WStringTokenizer tokenizer(start_, end_, L" =/");
+  tokenizer.set_options(WStringTokenizer::RETURN_DELIMS);
+
+  // Set up the quote chars so that we get quoted attribute values as single
+  // tokens.
+  tokenizer.set_quote_chars(L"\"'");
+
+  const bool PARSE_STATE_NAME = true;
+  const bool PARSE_STATE_VALUE = false;
+  bool parse_state = PARSE_STATE_NAME;
+
+  // Used to skip the first token, which is the tag name.
+  bool first_token_skipped = false;
+
+  // This is set during a loop iteration in which an '=' sign was spotted.
+  // It is used to filter out degenerate tags such as:
+  // <meta foo==bar>
+  bool last_token_was_delim = false;
+
+  // Set this if the attribute name has been found that we might then
+  // pick up the value in the next loop iteration.
+  bool attribute_name_found = false;
+
+  while (tokenizer.GetNext()) {
+    // If we have a whitespace delimiter, just keep going. Cases of this should
+    // be reduced by the CollapseWhitespace call. If we have an '=' character,
+    // we update our state and reiterate.
+    if (tokenizer.token_is_delim()) {
+      if (*tokenizer.token_begin() == L'=') {
+        if (last_token_was_delim) {
+          // Looks like we have a badly formed tag, just stop parsing now.
+          return false;
+        }
+        parse_state = !parse_state;
+        last_token_was_delim = true;
+      }
+      continue;
+    }
+
+    last_token_was_delim = false;
+
+    // The first non-delimiter token is the tag name, which we don't want.
+    if (!first_token_skipped) {
+      first_token_skipped = true;
+      continue;
+    }
+
+    if (PARSE_STATE_NAME == parse_state) {
+      // We have a tag name, check to see if it matches our target name:
+      if (::LowerCaseEqualsASCII(tokenizer.token_begin(), tokenizer.token_end(),
+                                 search_name_ascii.c_str())) {
+        attribute_name_found = true;
+        continue;
+      }
+    } else if (PARSE_STATE_VALUE == parse_state && attribute_name_found) {
+      attribute_value->start_ = tokenizer.token_begin();
+      attribute_value->end_ = tokenizer.token_end();
+
+      // Unquote the attribute value if need be.
+      attribute_value->UnQuote();
+
+      return true;
+    } else if (PARSE_STATE_VALUE == parse_state) {
+      // If we haven't found the attribute name we want yet, ignore this token
+      // and go back to looking for our name.
+      parse_state = PARSE_STATE_NAME;
+    }
+  }
+
+  return false;
+}
+
+bool HTMLScanner::StringRange::UnQuote() {
+  if (start_ + 2 > end_) {
+    // String's too short to be quoted, bail.
+    return false;
+  }
+
+  if ((*start_ == L'\'' && *(end_ - 1) == L'\'') ||
+      (*start_ == L'"' && *(end_ - 1) == L'"')) {
+    start_ = start_ + 1;
+    end_ = end_ - 1;
+    return true;
+  }
+
+  return false;
+}
+
+HTMLScanner::HTMLScanner(const wchar_t* html_string)
+    : html_string_(CollapseWhitespace(html_string, true)),
+      quotes_(kQuotes) {
+}
+
+void HTMLScanner::GetTagsByName(const wchar_t* name, StringRangeList* tag_list,
+                                const wchar_t* stop_tag) {
+  DCHECK(NULL != name);
+  DCHECK(NULL != tag_list);
+  DCHECK(NULL != stop_tag);
+
+  StringRange remaining_html(html_string_.begin(), html_string_.end());
+
+  std::wstring search_name(name);
+  TrimWhitespace(search_name, TRIM_ALL, &search_name);
+
+  // Use this so we can use the convenience method LowerCaseEqualsASCII()
+  // from string_util.h.
+  std::string search_name_ascii(WideToASCII(search_name));
+  std::string stop_tag_ascii(WideToASCII(stop_tag));
+
+  StringRange current_tag;
+  std::wstring current_name;
+  while (NextTag(&remaining_html, &current_tag)) {
+    if (current_tag.GetTagName(&current_name)) {
+      if (LowerCaseEqualsASCII(current_name, search_name_ascii.c_str())) {
+        tag_list->push_back(current_tag);
+      } else if (LowerCaseEqualsASCII(current_name, stop_tag_ascii.c_str())) {
+        // We hit the stop tag so it's time to go home.
+        break;
+      }
+    }
+  }
+}
+
+struct ScanState {
+  bool in_quote;
+  bool in_escape;
+  wchar_t quote_char;
+  ScanState() : in_quote(false), in_escape(false) {}
+};
+
+bool HTMLScanner::IsQuote(wchar_t c) {
+  return quotes_.find(c) != std::wstring::npos;
+}
+
+bool HTMLScanner::IsHTMLCommentClose(StringRange* html_string, StrPos pos) {
+  if (pos < html_string->end_ && pos > html_string->start_ + 2 &&
+      *pos == L'>') {
+    return *(pos-1) == L'-' && *(pos-2) == L'-';
+  }
+  return false;
+}
+
+bool HTMLScanner::NextTag(StringRange* html_string, StringRange* tag) {
+  DCHECK(NULL != html_string);
+  DCHECK(NULL != tag);
+
+  tag->start_ = html_string->start_;
+  while (tag->start_ < html_string->end_ && *tag->start_ != L'<') {
+    tag->start_++;
+  }
+
+  // we went past the end of the string.
+  if (tag->start_ >= html_string->end_) {
+    return false;
+  }
+
+  tag->end_ = tag->start_ + 1;
+
+  // Get the tag name to see if we are in an HTML comment. If we are, then
+  // don't consider quotes. This should work for example:
+  // <!-- foo ' --> <meta foo='bar'>
+  std::wstring tag_name;
+  StringRange start_range(tag->start_, html_string->end_);
+  start_range.GetTagName(&tag_name);
+  if (StartsWith(tag_name, L"!--", true)) {
+    // We're inside a comment tag, keep going until we get out of it.
+    while (tag->end_ < html_string->end_ &&
+           !IsHTMLCommentClose(html_string, tag->end_)) {
+      tag->end_++;
+    }
+  } else {
+    // Properly handle quoted strings within non-comment tags by maintaining
+    // some state while scanning. Specifically, we have to maintain state on
+    // whether we are inside a string, what the string terminating character
+    // will be and whether we are inside an escape sequence.
+    ScanState state;
+    while (tag->end_ < html_string->end_) {
+      if (state.in_quote) {
+        if (state.in_escape) {
+          state.in_escape = false;
+        } else if (*tag->end_ == '\\') {
+          state.in_escape = true;
+        } else if (*tag->end_ == state.quote_char) {
+          state.in_quote = false;
+        }
+      } else {
+        state.in_quote = IsQuote(state.quote_char = *tag->end_);
+      }
+
+      if (!state.in_quote && *tag->end_ == L'>') {
+        break;
+      }
+      tag->end_++;
+    }
+  }
+
+  // We hit the end_ but found no matching tag closure. Consider this an
+  // incomplete tag and do not report it.
+  if (tag->end_ >= html_string->end_)
+    return false;
+
+  // Modify html_string to point to just beyond the end_ of the current tag.
+  html_string->start_ = tag->end_ + 1;
+
+  return true;
+}
+