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/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim:set ts=2 sw=2 sts=2 et cindent: */
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
#include "TextDirectiveFinder.h"
#include "Document.h"
#include "TextDirectiveUtil.h"
#include "nsRange.h"
#include "fragmentdirectives_ffi_generated.h"
namespace mozilla::dom {
TextDirectiveFinder::TextDirectiveFinder(
Document& aDocument, nsTArray<TextDirective>&& aTextDirectives)
: mDocument(aDocument),
mUninvokedTextDirectives(std::move(aTextDirectives)) {}
bool TextDirectiveFinder::HasUninvokedDirectives() const {
return !mUninvokedTextDirectives.IsEmpty();
}
nsTArray<RefPtr<nsRange>> TextDirectiveFinder::FindTextDirectivesInDocument() {
if (mUninvokedTextDirectives.IsEmpty()) {
return {};
}
auto uri = TextDirectiveUtil::ShouldLog() && mDocument.GetDocumentURI()
? mDocument.GetDocumentURI()->GetSpecOrDefault()
: nsCString();
TEXT_FRAGMENT_LOG("Trying to find text directives in document '%s'.",
uri.Data());
mDocument.FlushPendingNotifications(FlushType::Layout);
// To invoke text directives, given as input a list of text directives text
// directives and a Document document, run these steps:
// 1. Let ranges be a list of ranges, initially empty.
nsTArray<RefPtr<nsRange>> textDirectiveRanges(
mUninvokedTextDirectives.Length());
// Additionally (not mentioned in the spec), remove all text directives from
// the input list to keep only the ones that are not found.
// This code runs repeatedly during a page load, so it is possible that the
// match for a text directive has not been parsed yet.
nsTArray<TextDirective> uninvokedTextDirectives(
mUninvokedTextDirectives.Length());
// 2. For each text directive directive of text directives:
for (TextDirective& textDirective : mUninvokedTextDirectives) {
// 2.1 If the result of running find a range from a text directive given
// directive and document is non-null, then append it to ranges.
if (RefPtr<nsRange> range = FindRangeForTextDirective(textDirective)) {
textDirectiveRanges.AppendElement(range);
TEXT_FRAGMENT_LOG("Found text directive '%s'",
ToString(textDirective).c_str());
} else {
uninvokedTextDirectives.AppendElement(std::move(textDirective));
}
}
if (TextDirectiveUtil::ShouldLog()) {
if (uninvokedTextDirectives.Length() == mUninvokedTextDirectives.Length()) {
TEXT_FRAGMENT_LOG(
"Did not find any of the %zu uninvoked text directives.",
mUninvokedTextDirectives.Length());
} else {
TEXT_FRAGMENT_LOG(
"Found %zu of %zu text directives in the document.",
mUninvokedTextDirectives.Length() - uninvokedTextDirectives.Length(),
mUninvokedTextDirectives.Length());
}
if (uninvokedTextDirectives.IsEmpty()) {
TEXT_FRAGMENT_LOG("No uninvoked text directives left.");
} else {
TEXT_FRAGMENT_LOG("There are %zu uninvoked text directives left:",
uninvokedTextDirectives.Length());
for (size_t index = 0; index < uninvokedTextDirectives.Length();
++index) {
TEXT_FRAGMENT_LOG(" [%zu]: %s", index,
ToString(uninvokedTextDirectives[index]).c_str());
}
}
}
mUninvokedTextDirectives = std::move(uninvokedTextDirectives);
// 3. Return ranges.
return textDirectiveRanges;
}
RefPtr<nsRange> TextDirectiveFinder::FindRangeForTextDirective(
const TextDirective& aTextDirective) {
TEXT_FRAGMENT_LOG("Find range for text directive '%s'.",
ToString(aTextDirective).c_str());
// 1. Let searchRange be a range with start (document, 0) and end (document,
// document’s length)
ErrorResult rv;
RefPtr<nsRange> searchRange =
nsRange::Create(&mDocument, 0, &mDocument, mDocument.Length(), rv);
if (rv.Failed()) {
return nullptr;
}
// 2. While searchRange is not collapsed:
while (!searchRange->Collapsed()) {
// 2.1. Let potentialMatch be null.
RefPtr<nsRange> potentialMatch;
// 2.2. If parsedValues’s prefix is not null:
if (!aTextDirective.prefix.IsEmpty()) {
// 2.2.1. Let prefixMatch be the the result of running the find a string
// in range steps with query parsedValues’s prefix, searchRange
// searchRange, wordStartBounded true and wordEndBounded false.
RefPtr<nsRange> prefixMatch = TextDirectiveUtil::FindStringInRange(
searchRange, aTextDirective.prefix, true, false);
// 2.2.2. If prefixMatch is null, return null.
if (!prefixMatch) {
TEXT_FRAGMENT_LOG(
"Did not find prefix '%s'. The text directive does not exist "
"in the document.",
NS_ConvertUTF16toUTF8(aTextDirective.prefix).Data());
return nullptr;
}
TEXT_FRAGMENT_LOG("Did find prefix '%s'.",
NS_ConvertUTF16toUTF8(aTextDirective.prefix).Data());
// 2.2.3. Set searchRange’s start to the first boundary point after
// prefixMatch’s start
const RangeBoundary boundaryPoint =
TextDirectiveUtil::MoveRangeBoundaryOneWord(
{prefixMatch->GetStartContainer(), prefixMatch->StartOffset()},
TextScanDirection::Right);
if (!boundaryPoint.IsSetAndValid()) {
return nullptr;
}
searchRange->SetStart(boundaryPoint.AsRaw(), rv);
if (rv.Failed()) {
return nullptr;
}
// 2.2.4. Let matchRange be a range whose start is prefixMatch’s end and
// end is searchRange’s end.
RefPtr<nsRange> matchRange = nsRange::Create(
prefixMatch->GetEndContainer(), prefixMatch->EndOffset(),
searchRange->GetEndContainer(), searchRange->EndOffset(), rv);
if (rv.Failed()) {
return nullptr;
}
// 2.2.5. Advance matchRange’s start to the next non-whitespace position.
TextDirectiveUtil::AdvanceStartToNextNonWhitespacePosition(*matchRange);
// 2.2.6. If matchRange is collapsed return null.
// (This can happen if prefixMatch’s end or its subsequent non-whitespace
// position is at the end of the document.)
if (matchRange->Collapsed()) {
return nullptr;
}
// 2.2.7. Assert: matchRange’s start node is a Text node.
// (matchRange’s start now points to the next non-whitespace text data
// following a matched prefix.)
MOZ_ASSERT(matchRange->GetStartContainer()->IsText());
// 2.2.8. Let mustEndAtWordBoundary be true if parsedValues’s end is
// non-null or parsedValues’s suffix is null, false otherwise.
const bool mustEndAtWordBoundary =
!aTextDirective.end.IsEmpty() || aTextDirective.suffix.IsEmpty();
// 2.2.9. Set potentialMatch to the result of running the find a string in
// range steps with query parsedValues’s start, searchRange matchRange,
// wordStartBounded false, and wordEndBounded mustEndAtWordBoundary.
potentialMatch = TextDirectiveUtil::FindStringInRange(
matchRange, aTextDirective.start, false, mustEndAtWordBoundary);
// 2.2.10. If potentialMatch is null, return null.
if (!potentialMatch) {
TEXT_FRAGMENT_LOG(
"Did not find start '%s'. The text directive does not exist "
"in the document.",
NS_ConvertUTF16toUTF8(aTextDirective.start).Data());
return nullptr;
}
TEXT_FRAGMENT_LOG("Did find start '%s'.",
NS_ConvertUTF16toUTF8(aTextDirective.start).Data());
// 2.2.11. If potentialMatch’s start is not matchRange’s start, then
// continue.
// (In this case, we found a prefix but it was followed by something other
// than a matching text so we’ll continue searching for the next instance
// of prefix.)
if (potentialMatch->StartRef() != matchRange->StartRef()) {
TEXT_FRAGMENT_LOG(
"The prefix is not directly followed by the start element. "
"Discarding this attempt.");
continue;
}
}
// 2.3. Otherwise:
else {
// 2.3.1. Let mustEndAtWordBoundary be true if parsedValues’s end is
// non-null or parsedValues’s suffix is null, false otherwise.
const bool mustEndAtWordBoundary =
!aTextDirective.end.IsEmpty() || aTextDirective.suffix.IsEmpty();
// 2.3.2. Set potentialMatch to the result of running the find a string in
// range steps with query parsedValues’s start, searchRange searchRange,
// wordStartBounded true, and wordEndBounded mustEndAtWordBoundary.
potentialMatch = TextDirectiveUtil::FindStringInRange(
searchRange, aTextDirective.start, true, mustEndAtWordBoundary);
// 2.3.3. If potentialMatch is null, return null.
if (!potentialMatch) {
TEXT_FRAGMENT_LOG(
"Did not find start '%s'. The text directive does not exist "
"in the document.",
NS_ConvertUTF16toUTF8(aTextDirective.start).Data());
return nullptr;
}
// 2.3.4. Set searchRange’s start to the first boundary point after
// potentialMatch’s start
RangeBoundary newRangeBoundary =
TextDirectiveUtil::MoveRangeBoundaryOneWord(
{potentialMatch->GetStartContainer(),
potentialMatch->StartOffset()},
TextScanDirection::Right);
if (!newRangeBoundary.IsSetAndValid()) {
return nullptr;
}
searchRange->SetStart(newRangeBoundary.AsRaw(), rv);
if (rv.Failed()) {
return nullptr;
}
}
// 2.4. Let rangeEndSearchRange be a range whose start is potentialMatch’s
// end and whose end is searchRange’s end.
RefPtr<nsRange> rangeEndSearchRange = nsRange::Create(
potentialMatch->GetEndContainer(), potentialMatch->EndOffset(),
searchRange->GetEndContainer(), searchRange->EndOffset(), rv);
if (rv.Failed()) {
return nullptr;
}
// 2.5. While rangeEndSearchRange is not collapsed:
while (!rangeEndSearchRange->Collapsed()) {
// 2.5.1. If parsedValues’s end item is non-null, then:
if (!aTextDirective.end.IsEmpty()) {
// 2.5.1.1. Let mustEndAtWordBoundary be true if parsedValues’s suffix
// is null, false otherwise.
const bool mustEndAtWordBoundary = aTextDirective.suffix.IsEmpty();
// 2.5.1.2. Let endMatch be the result of running the find a string in
// range steps with query parsedValues’s end, searchRange
// rangeEndSearchRange, wordStartBounded true, and wordEndBounded
// mustEndAtWordBoundary.
RefPtr<nsRange> endMatch = TextDirectiveUtil::FindStringInRange(
rangeEndSearchRange, aTextDirective.end, true,
mustEndAtWordBoundary);
// 2.5.1.3. If endMatch is null then return null.
if (!endMatch) {
TEXT_FRAGMENT_LOG(
"Did not find end '%s'. The text directive does not exist "
"in the document.",
NS_ConvertUTF16toUTF8(aTextDirective.end).Data());
return nullptr;
}
// 2.5.1.4. Set potentialMatch’s end to endMatch’s end.
potentialMatch->SetEnd(endMatch->GetEndContainer(),
endMatch->EndOffset());
}
// 2.5.2. Assert: potentialMatch is non-null, not collapsed and represents
// a range exactly containing an instance of matching text.
MOZ_ASSERT(potentialMatch && !potentialMatch->Collapsed());
// 2.5.3. If parsedValues’s suffix is null, return potentialMatch.
if (aTextDirective.suffix.IsEmpty()) {
TEXT_FRAGMENT_LOG("Did find a match.");
return potentialMatch;
}
// 2.5.4. Let suffixRange be a range with start equal to potentialMatch’s
// end and end equal to searchRange’s end.
RefPtr<nsRange> suffixRange = nsRange::Create(
potentialMatch->GetEndContainer(), potentialMatch->EndOffset(),
searchRange->GetEndContainer(), searchRange->EndOffset(), rv);
if (rv.Failed()) {
return nullptr;
}
// 2.5.5. Advance suffixRange's start to the next non-whitespace position.
TextDirectiveUtil::AdvanceStartToNextNonWhitespacePosition(*suffixRange);
// 2.5.6. Let suffixMatch be result of running the find a string in range
// steps with query parsedValue's suffix, searchRange suffixRange,
// wordStartBounded false, and wordEndBounded true.
RefPtr<nsRange> suffixMatch = TextDirectiveUtil::FindStringInRange(
suffixRange, aTextDirective.suffix, false, true);
// 2.5.7. If suffixMatch is null, return null.
// (If the suffix doesn't appear in the remaining text of the document,
// there's no possible way to make a match.)
if (!suffixMatch) {
TEXT_FRAGMENT_LOG(
"Did not find suffix '%s'. The text directive does not exist "
"in the document.",
NS_ConvertUTF16toUTF8(aTextDirective.suffix).Data());
return nullptr;
}
// 2.5.8. If suffixMatch's start is suffixRange's start, return
// potentialMatch.
if (suffixMatch->GetStartContainer() ==
suffixRange->GetStartContainer() &&
suffixMatch->StartOffset() == suffixRange->StartOffset()) {
TEXT_FRAGMENT_LOG("Did find a match.");
return potentialMatch;
}
// 2.5.9. If parsedValue's end item is null then break;
// (If this is an exact match and the suffix doesn’t match, start
// searching for the next range start by breaking out of this loop without
// rangeEndSearchRange being collapsed. If we’re looking for a range
// match, we’ll continue iterating this inner loop since the range start
// will already be correct.)
if (aTextDirective.end.IsEmpty()) {
break;
}
// 2.5.10. Set rangeEndSearchRange's start to potentialMatch's end.
// (Otherwise, it is possible that we found the correct range start, but
// not the correct range end. Continue the inner loop to keep searching
// for another matching instance of rangeEnd.)
rangeEndSearchRange->SetStart(potentialMatch->GetEndContainer(),
potentialMatch->EndOffset());
}
// 2.6. If rangeEndSearchRange is collapsed then:
if (rangeEndSearchRange->Collapsed()) {
// 2.6.1. Assert parsedValue's end item is non-null.
// (This can only happen for range matches due to the break for exact
// matches in step 9 of the above loop. If we couldn’t find a valid
// rangeEnd+suffix pair anywhere in the doc then there’s no possible way
// to make a match.)
// ----
// XXX(:jjaschke): Not too sure about this. If a text directive is only
// defined by a (prefix +) start element, and the start element happens to
// be at the end of the document, `rangeEndSearchRange` could be
// collapsed. Therefore, the loop in section 2.5 does not run. Also,
// if there would be either an `end` and/or a `suffix`, this would assert
// instead of returning `nullptr`, indicating that there's no match.
// Instead, the following would make the algorithm more safe:
// if there is no end or suffix, the potential match is actually a match,
// so return it. Otherwise, the text directive can't be in the document,
// therefore return nullptr.
if (aTextDirective.end.IsEmpty() && aTextDirective.suffix.IsEmpty()) {
TEXT_FRAGMENT_LOG(
"rangeEndSearchRange was collapsed, no end or suffix "
"present. Returning a match");
return potentialMatch;
}
TEXT_FRAGMENT_LOG(
"rangeEndSearchRange was collapsed, there is an end or "
"suffix. There can't be a match.");
return nullptr;
}
}
// 3. Return null.
TEXT_FRAGMENT_LOG("Did not find a match.");
return nullptr;
}
} // namespace mozilla::dom