Fix missing text on nonexistent font file

Fix for bug 15570313 "Missing text on nonexistent font file"

This patch makes sure that the lastChar and mInstances arrays are in
sync with each other even when a FontFamily being added has no valid
fonts in it. Previously, when they got out of sync, unicode coverage
calculation would be wrong, resulting in missing text.

Change-Id: I69c727ef69e2c61e2b2d6b81d5a28c806327f865

1 files changed, 7 insertions, 6 deletions

diff --git a/libs/minikin/FontCollection.cpp b/libs/minikin/FontCollection.cpp
index 6115ecc..45e5d06 100644
--- a/libs/minikin/FontCollection.cpp
+++ b/libs/minikin/FontCollection.cpp
@@ -46,12 +46,6 @@ FontCollection::FontCollection(const vector<FontFamily*>& typefaces) :
     const FontStyle defaultStyle;
     for (size_t i = 0; i < nTypefaces; i++) {
         FontFamily* family = typefaces[i];
-        family->RefLocked();
-        FontInstance dummy;
-        mInstances.push_back(dummy);  // emplace_back would be better
-        FontInstance* instance = &mInstances.back();
-        instance->mFamily = family;
-        instance->mCoverage = new SparseBitSet;
         MinikinFont* typeface = family->getClosestMatch(defaultStyle).font;
         if (typeface == NULL) {
             ALOGE("FontCollection: closest match was null");
@@ -59,6 +53,12 @@ FontCollection::FontCollection(const vector<FontFamily*>& typefaces) :
             // checks upstream to prevent empty/invalid FontFamily objects
             continue;
         }
+        family->RefLocked();
+        FontInstance dummy;
+        mInstances.push_back(dummy);  // emplace_back would be better
+        FontInstance* instance = &mInstances.back();
+        instance->mFamily = family;
+        instance->mCoverage = new SparseBitSet;
 #ifdef VERBOSE_DEBUG
         ALOGD("closest match = %p, family size = %d\n", typeface, family->getNumFonts());
 #endif
@@ -75,6 +75,7 @@ FontCollection::FontCollection(const vector<FontFamily*>& typefaces) :
         mMaxChar = max(mMaxChar, instance->mCoverage->length());
         lastChar.push_back(instance->mCoverage->nextSetBit(0));
     }
+    nTypefaces = mInstances.size();
     size_t nPages = (mMaxChar + kPageMask) >> kLogCharsPerPage;
     size_t offset = 0;
     for (size_t i = 0; i < nPages; i++) {