Make skpinfo able to inspect SK_PICT_TYPEFACE_TAG blocks

GOLD_TRYBOT_URL= https://gold.skia.org/search2?unt=true&query=source_type%3Dgm&master=false&issue=1732263003

BUG=skia:4691

Review URL: https://codereview.chromium.org/1732263003

6 files changed, 54 insertions, 22 deletions

diff --git a/src/core/SkFontDescriptor.cpp b/src/core/SkFontDescriptor.cpp
index 8348d5fdba..f477a2d695 100644
--- a/src/core/SkFontDescriptor.cpp
+++ b/src/core/SkFontDescriptor.cpp
@@ -58,8 +58,8 @@ static void write_uint(SkWStream* stream, size_t n, uint32_t id) {
     stream->writePackedUInt(n);
 }
 
-SkFontDescriptor::SkFontDescriptor(SkStream* stream) {
-    fStyle = (SkTypeface::Style)stream->readPackedUInt();
+bool SkFontDescriptor::Deserialize(SkStream* stream, SkFontDescriptor* result) {
+    result->fStyle = (SkTypeface::Style)stream->readPackedUInt();
 
     SkAutoSTMalloc<4, SkFixed> axis;
     size_t axisCount = 0;
@@ -67,13 +67,13 @@ SkFontDescriptor::SkFontDescriptor(SkStream* stream) {
     for (size_t id; (id = stream->readPackedUInt()) != kSentinel;) {
         switch (id) {
             case kFontFamilyName:
-                read_string(stream, &fFamilyName);
+                read_string(stream, &result->fFamilyName);
                 break;
             case kFullName:
-                read_string(stream, &fFullName);
+                read_string(stream, &result->fFullName);
                 break;
             case kPostscriptName:
-                read_string(stream, &fPostscriptName);
+                read_string(stream, &result->fPostscriptName);
                 break;
             case kFontAxes:
                 axisCount = read_uint(stream);
@@ -90,7 +90,7 @@ SkFontDescriptor::SkFontDescriptor(SkStream* stream) {
                 break;
             default:
                 SkDEBUGFAIL("Unknown id used by a font descriptor");
-                return;
+                return false;
         }
     }
 
@@ -98,9 +98,14 @@ SkFontDescriptor::SkFontDescriptor(SkStream* stream) {
     if (length > 0) {
         SkAutoTUnref<SkData> data(SkData::NewUninitialized(length));
         if (stream->read(data->writable_data(), length) == length) {
-            fFontData.reset(new SkFontData(new SkMemoryStream(data), index, axis, axisCount));
+            result->fFontData.reset(new SkFontData(new SkMemoryStream(data),
+                                                   index, axis, axisCount));
+        } else {
+            SkDEBUGFAIL("Could not read font data");
+            return false;
         }
     }
+    return true;
 }
 
 void SkFontDescriptor::serialize(SkWStream* stream) {
diff --git a/src/core/SkFontDescriptor.h b/src/core/SkFontDescriptor.h
index 21fecdc416..095ecce60a 100644
--- a/src/core/SkFontDescriptor.h
+++ b/src/core/SkFontDescriptor.h
@@ -51,7 +51,7 @@ class SkFontDescriptor : SkNoncopyable {
 public:
     SkFontDescriptor(SkTypeface::Style = SkTypeface::kNormal);
     // Does not affect ownership of SkStream.
-    SkFontDescriptor(SkStream*);
+    static bool Deserialize(SkStream*, SkFontDescriptor* result);
 
     void serialize(SkWStream*);
 
diff --git a/src/core/SkPaint.cpp b/src/core/SkPaint.cpp
index 638e251b36..060e905ec7 100644
--- a/src/core/SkPaint.cpp
+++ b/src/core/SkPaint.cpp
@@ -2123,15 +2123,19 @@ void SkPaint::toString(SkString* str) const {
         SkDynamicMemoryWStream ostream;
         typeface->serialize(&ostream);
         SkAutoTDelete<SkStreamAsset> istream(ostream.detachAsStream());
-        SkFontDescriptor descriptor(istream);
-
-        str->append("<dt>Font Family Name:</dt><dd>");
-        str->append(descriptor.getFamilyName());
-        str->append("</dd><dt>Font Full Name:</dt><dd>");
-        str->append(descriptor.getFullName());
-        str->append("</dd><dt>Font PS Name:</dt><dd>");
-        str->append(descriptor.getPostscriptName());
-        str->append("</dd>");
+
+        SkFontDescriptor descriptor;
+        if (!SkFontDescriptor::Deserialize(istream, &descriptor)) {
+            str->append("<dt>FontDescriptor deserialization failed</dt>");
+        } else {
+            str->append("<dt>Font Family Name:</dt><dd>");
+            str->append(descriptor.getFamilyName());
+            str->append("</dd><dt>Font Full Name:</dt><dd>");
+            str->append(descriptor.getFullName());
+            str->append("</dd><dt>Font PS Name:</dt><dd>");
+            str->append(descriptor.getPostscriptName());
+            str->append("</dd>");
+        }
     }
 
     str->append("<dt>TextSize:</dt><dd>");
diff --git a/src/core/SkTypeface.cpp b/src/core/SkTypeface.cpp
index e6a9b4d66c..8d4233eac1 100644
--- a/src/core/SkTypeface.cpp
+++ b/src/core/SkTypeface.cpp
@@ -180,7 +180,12 @@ SkTypeface* SkTypeface::Deserialize(SkStream* stream) {
     if (gDeserializeTypefaceDelegate) {
         return (*gDeserializeTypefaceDelegate)(stream);
     }
-    SkFontDescriptor desc(stream);
+
+    SkFontDescriptor desc;
+    if (!SkFontDescriptor::Deserialize(stream, &desc)) {
+        return nullptr;
+    }
+
     SkFontData* data = desc.detachFontData();
     if (data) {
         SkTypeface* typeface = SkTypeface::CreateFromFontData(data);
diff --git a/src/utils/SkWhitelistTypefaces.cpp b/src/utils/SkWhitelistTypefaces.cpp
index d3ffe98d16..66d32188a0 100644
--- a/src/utils/SkWhitelistTypefaces.cpp
+++ b/src/utils/SkWhitelistTypefaces.cpp
@@ -184,7 +184,11 @@ void WhitelistSerializeTypeface(const SkTypeface* tf, SkWStream* wstream) {
 }
 
 SkTypeface* WhitelistDeserializeTypeface(SkStream* stream) {
-    SkFontDescriptor desc(stream);
+    SkFontDescriptor desc;
+    if (!SkFontDescriptor::Deserialize(stream, &desc)) {
+        return nullptr;
+    }
+
     SkFontData* data = desc.detachFontData();
     if (data) {
         SkTypeface* typeface = SkTypeface::CreateFromFontData(data);
diff --git a/tools/skpinfo.cpp b/tools/skpinfo.cpp
index c7fd8c8708..4b65cb8a8c 100644
--- a/tools/skpinfo.cpp
+++ b/tools/skpinfo.cpp
@@ -9,6 +9,7 @@
 #include "SkPicture.h"
 #include "SkPictureData.h"
 #include "SkStream.h"
+#include "SkFontDescriptor.h"
 
 DEFINE_string2(input, i, "", "skp on which to report");
 DEFINE_bool2(version, v, true, "version");
@@ -107,13 +108,26 @@ int tool_main(int argc, char** argv) {
                 SkDebugf("SK_PICT_FACTORY_TAG %d\n", chunkSize);
             }
             break;
-        case SK_PICT_TYPEFACE_TAG:
+        case SK_PICT_TYPEFACE_TAG: {
             if (FLAGS_tags && !FLAGS_quiet) {
                 SkDebugf("SK_PICT_TYPEFACE_TAG %d\n", chunkSize);
-                SkDebugf("Exiting early due to format limitations\n");
             }
-            return kSuccess;       // TODO: need to store size in bytes
+
+            const int count = SkToInt(chunkSize);
+            for (int i = 0; i < count; i++) {
+                SkFontDescriptor desc;
+                if (!SkFontDescriptor::Deserialize(&stream, &desc)) {
+                    if (!FLAGS_quiet) {
+                        SkDebugf("File corruption in SkFontDescriptor\n");
+                    }
+                    return kInvalidTag;
+                }
+            }
+
+            // clear this since we've consumed all the typefaces
+            chunkSize = 0;
             break;
+        }
         case SK_PICT_PICTURE_TAG:
             if (FLAGS_tags && !FLAGS_quiet) {
                 SkDebugf("SK_PICT_PICTURE_TAG %d\n", chunkSize);