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Bug 1554208 - patch 4 - Make the FontNameCache that we use to store the font list in the startupCache use a more robust and extensible serialization. r=jwatt

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I'll need to add a couple of extra fields to the cache records, and realized that the current format
looks really fragile; in theory, it'd break if a font name ever contained a comma or semicolon
(unlikely though that may be). So let's fix it to be a bit more robust before we add to it further.
Using control characters from the C0 range to delimit fields/records, instead of ASCII punctuation,
removes the (tiny) risk of conflict with characters that actually occur in a name, and using
distinct field and record separators means that we can better check that the records we're loading
from the cache actually match the expected format.

(Given that the startup cache gets re-created when the build ID is updated, a change in the format
between versions wasn't going to cause problems for users; their old cache just gets blown away
when upgrading. Still, a little more robustness seems like a good thing.)

Differential Revision: https://phabricator.services.mozilla.com/D36109

--HG--
extra : moz-landing-system : lando
This commit is contained in:
Jonathan Kew 2019-07-12 15:33:35 +00:00
parent 01e8403527
commit 9f9125a4d0
2 changed files with 129 additions and 71 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

193
gfx/thebes/gfxFT2FontList.cpp
View File

@ -697,6 +697,19 @@ void FT2FontFamily::AddFacesToFontList(nsTArray<FontListEntry>* aFontList) {
class FontNameCache {
public:
// Delimiters used in the cached font-list records we store in startupCache
static const char kFileSep = 0x1c;
static const char kGroupSep = 0x1d;
static const char kRecordSep = 0x1e;
static const char kFieldSep = 0x1f;
// Separator for font property ranges; we only look for this within a
// field that holds a serialized FontPropertyValue or Range, so there's no
// risk of conflicting with printable characters in font names.
// Note that this must be a character that will terminate strtof() parsing
// of a number.
static const char kRangeSep = ':';
// Creates the object but does NOT load the cached data from the startup
// cache; call Init() after creation to do that.
FontNameCache() : mMap(&mOps, sizeof(FNCMapEntry), 0), mWriteNeeded(false) {
@ -731,13 +744,13 @@ class FontNameCache {
continue;
}
buf.Append(entry->mFilename);
buf.Append(';');
buf.Append(kGroupSep);
buf.Append(entry->mFaces);
buf.Append(';');
buf.Append(kGroupSep);
buf.AppendInt(entry->mTimestamp);
buf.Append(';');
buf.Append(kGroupSep);
buf.AppendInt(entry->mFilesize);
buf.Append(';');
buf.Append(kFileSep);
}
LOG(("putting FontNameCache to " CACHE_KEY ", length %u",
@ -765,25 +778,48 @@ class FontNameCache {
mMap.Clear();
mWriteNeeded = false;
const char* beginning = buf.get();
const char* end = strchr(beginning, ';');
while (end) {
nsCString filename(beginning, end - beginning);
beginning = end + 1;
if (!(end = strchr(beginning, ';'))) {
const char* cur = buf.get();
while (const char* fileEnd = strchr(cur, kFileSep)) {
// The cached record for one file is at [cur, fileEnd].
// Find end of field that starts at aStart, terminated by kGroupSep or
// end of record.
auto endOfField = [=](const char* aStart) -> const char* {
MOZ_ASSERT(aStart <= fileEnd);
const char* end = static_cast<const char*>(
memchr(aStart, kGroupSep, fileEnd - aStart));
if (end) {
return end;
}
return fileEnd;
};
// Advance aStart and aEnd to indicate the range of the next field and
// return true, or just return false if already at end of record.
auto nextField = [=](const char*& aStart, const char*& aEnd) -> bool {
if (aEnd < fileEnd) {
aStart = aEnd + 1;
aEnd = endOfField(aStart);
return true;
}
return false;
};
const char* end = endOfField(cur);
nsCString filename(cur, end - cur);
if (!nextField(cur, end)) {
break;
}
nsCString faceList(beginning, end - beginning);
beginning = end + 1;
if (!(end = strchr(beginning, ';'))) {
nsCString faceList(cur, end - cur);
if (!nextField(cur, end)) {
break;
}
uint32_t timestamp = strtoul(beginning, nullptr, 10);
beginning = end + 1;
if (!(end = strchr(beginning, ';'))) {
uint32_t timestamp = strtoul(cur, nullptr, 10);
if (!nextField(cur, end)) {
break;
}
uint32_t filesize = strtoul(beginning, nullptr, 10);
uint32_t filesize = strtoul(cur, nullptr, 10);
auto mapEntry =
static_cast<FNCMapEntry*>(mMap.Add(filename.get(), fallible));
@ -797,8 +833,7 @@ class FontNameCache {
mapEntry->mFileExists = false;
}
beginning = end + 1;
end = strchr(beginning, ';');
cur = fileEnd + 1;
}
}
@ -926,59 +961,75 @@ gfxFT2FontList::~gfxFT2FontList() {
}
}
void gfxFT2FontList::AppendFacesFromCachedFaceList(const nsCString& aFileName,
bool gfxFT2FontList::AppendFacesFromCachedFaceList(const nsCString& aFileName,
const nsCString& aFaceList,
StandardFile aStdFile) {
const char* beginning = aFaceList.get();
const char* end = strchr(beginning, ',');
while (end) {
nsAutoCString familyName(beginning, end - beginning);
const char* start = aFaceList.get();
int count = 0;
while (const char* recEnd = strchr(start, FontNameCache::kRecordSep)) {
auto endOfField = [=](const char* aStart) -> const char* {
MOZ_ASSERT(aStart <= recEnd);
const char* end = static_cast<const char*>(
memchr(aStart, FontNameCache::kFieldSep, recEnd - aStart));
if (end) {
return end;
}
return recEnd;
};
auto nextField = [=](const char*& aStart, const char*& aEnd) -> bool {
if (aEnd < recEnd) {
aStart = aEnd + 1;
aEnd = endOfField(aStart);
return true;
}
return false;
};
const char* end = endOfField(start);
nsAutoCString familyName(start, end - start);
ToLowerCase(familyName);
beginning = end + 1;
if (!(end = strchr(beginning, ','))) {
if (!nextField(start, end)) {
break;
}
nsAutoCString faceName(beginning, end - beginning);
nsAutoCString faceName(start, end - start);
beginning = end + 1;
if (!(end = strchr(beginning, ','))) {
if (!nextField(start, end)) {
break;
}
uint32_t index = strtoul(beginning, nullptr, 10);
uint32_t index = strtoul(start, nullptr, 10);
beginning = end + 1;
if (!(end = strchr(beginning, ','))) {
if (!nextField(start, end)) {
break;
}
nsAutoCString minStyle(beginning, end - beginning);
nsAutoCString minStyle(start, end - start);
nsAutoCString maxStyle(minStyle);
int32_t colon = minStyle.FindChar(':');
int32_t colon = minStyle.FindChar(FontNameCache::kRangeSep);
if (colon > 0) {
maxStyle.Assign(minStyle.BeginReading() + colon + 1);
minStyle.Truncate(colon);
}
beginning = end + 1;
if (!(end = strchr(beginning, ','))) {
if (!nextField(start, end)) {
break;
}
char* limit;
float minWeight = strtof(beginning, &limit);
float minWeight = strtof(start, &limit);
float maxWeight;
if (*limit == ':' && limit + 1 < end) {
if (*limit == FontNameCache::kRangeSep && limit + 1 < end) {
maxWeight = strtof(limit + 1, nullptr);
} else {
maxWeight = minWeight;
}
beginning = end + 1;
if (!(end = strchr(beginning, ','))) {
if (!nextField(start, end)) {
break;
}
float minStretch = strtof(beginning, &limit);
float minStretch = strtof(start, &limit);
float maxStretch;
if (*limit == ':' && limit + 1 < end) {
if (*limit == FontNameCache::kRangeSep && limit + 1 < end) {
maxStretch = strtof(limit + 1, nullptr);
} else {
maxStretch = minStretch;
@ -994,34 +1045,36 @@ void gfxFT2FontList::AppendFacesFromCachedFaceList(const nsCString& aFileName,
.AsScalar(),
index);
AppendFaceFromFontListEntry(fle, aStdFile);
count++;
beginning = end + 1;
end = strchr(beginning, ',');
start = recEnd + 1;
}
return count > 0;
}
static void AppendToFaceList(nsCString& aFaceList, nsACString& aFamilyName,
FT2FontEntry* aFontEntry) {
void FT2FontEntry::AppendToFaceList(nsCString& aFaceList,
nsACString& aFamilyName) {
aFaceList.Append(aFamilyName);
aFaceList.Append(',');
aFaceList.Append(aFontEntry->Name());
aFaceList.Append(',');
aFaceList.AppendInt(aFontEntry->mFTFontIndex);
aFaceList.Append(',');
aFaceList.Append(FontNameCache::kFieldSep);
aFaceList.Append(Name());
aFaceList.Append(FontNameCache::kFieldSep);
aFaceList.AppendInt(mFTFontIndex);
aFaceList.Append(FontNameCache::kFieldSep);
// Note that ToString() appends to the destination string without
// replacing existing contents (see FontPropertyTypes.h)
aFontEntry->SlantStyle().Min().ToString(aFaceList);
aFaceList.Append(':');
aFontEntry->SlantStyle().Max().ToString(aFaceList);
aFaceList.Append(',');
aFaceList.AppendFloat(aFontEntry->Weight().Min().ToFloat());
aFaceList.Append(':');
aFaceList.AppendFloat(aFontEntry->Weight().Max().ToFloat());
aFaceList.Append(',');
aFaceList.AppendFloat(aFontEntry->Stretch().Min().Percentage());
aFaceList.Append(':');
aFaceList.AppendFloat(aFontEntry->Stretch().Max().Percentage());
aFaceList.Append(',');
SlantStyle().Min().ToString(aFaceList);
aFaceList.Append(FontNameCache::kRangeSep);
SlantStyle().Max().ToString(aFaceList);
aFaceList.Append(FontNameCache::kFieldSep);
aFaceList.AppendFloat(Weight().Min().ToFloat());
aFaceList.Append(FontNameCache::kRangeSep);
aFaceList.AppendFloat(Weight().Max().ToFloat());
aFaceList.Append(FontNameCache::kFieldSep);
aFaceList.AppendFloat(Stretch().Min().Percentage());
aFaceList.Append(FontNameCache::kRangeSep);
aFaceList.AppendFloat(Stretch().Max().Percentage());
aFaceList.Append(FontNameCache::kRecordSep);
}
void FT2FontEntry::CheckForBrokenFont(gfxFontFamily* aFamily) {
@ -1065,9 +1118,10 @@ void gfxFT2FontList::AppendFacesFromFontFile(const nsCString& aFileName,
int statRetval = stat(aFileName.get(), &s);
if (!cachedFaceList.IsEmpty() && 0 == statRetval &&
uint32_t(s.st_mtime) == timestamp && s.st_size == filesize) {
LOG(("using cached font info for %s", aFileName.get()));
AppendFacesFromCachedFaceList(aFileName, cachedFaceList, aStdFile);
return;
if (AppendFacesFromCachedFaceList(aFileName, cachedFaceList, aStdFile)) {
LOG(("using cached font info for %s", aFileName.get()));
return;
}
}
FT_Face dummy = Factory::NewFTFace(nullptr, aFileName.get(), -1);
@ -1162,7 +1216,7 @@ void gfxFT2FontList::AddFaceToList(const nsCString& aEntryName, uint32_t aIndex,
fe->CheckForBrokenFont(family);
AppendToFaceList(aFaceList, name, fe);
fe->AppendToFaceList(aFaceList, name);
if (LOG_ENABLED()) {
nsAutoCString weightString;
fe->Weight().ToString(weightString);
@ -1187,8 +1241,9 @@ void gfxFT2FontList::AppendFacesFromOmnijarEntry(nsZipArchive* aArchive,
uint32_t filesize, timestamp;
aCache->GetInfoForFile(aEntryName, faceList, &timestamp, &filesize);
if (faceList.Length() > 0) {
AppendFacesFromCachedFaceList(aEntryName, faceList);
return;
if (AppendFacesFromCachedFaceList(aEntryName, faceList)) {
return;
}
}
}

7
gfx/thebes/gfxFT2FontList.h
View File

@ -87,6 +87,8 @@ class FT2FontEntry : public gfxFontEntry {
FT_MM_Var* GetMMVar() override;
void AppendToFaceList(nsCString& aFaceList, nsACString& aFamilyName);
void AddSizeOfExcludingThis(mozilla::MallocSizeOf aMallocSizeOf,
FontListSizes* aSizes) const override;
void AddSizeOfIncludingThis(mozilla::MallocSizeOf aMallocSizeOf,
@ -161,8 +163,9 @@ class gfxFT2FontList : public gfxPlatformFontList {
const nsCString& aEntryName,
FontNameCache* aCache, bool aJarChanged);
// the defaults here are suitable for reading bundled fonts from omnijar
void AppendFacesFromCachedFaceList(const nsCString& aFileName,
// Returns true if it is able to read at least one face entry; false if no
// usable face entry was found.
bool AppendFacesFromCachedFaceList(const nsCString& aFileName,
const nsCString& aFaceList,
StandardFile aStdFile = kStandard);