Move coverage bitmap from FontCollection to FontFamily

This will significantly reduce memory usage and also speed the creation
of new font families. In particular, the coverage bitmaps for the fonts
in the fallback stack will be computed once in the Zygote, rather than
separately in each app process.

Bug: 17756900
Change-Id: I66f5706bddd4658d78fe5b709f7251ca9d2ff4f8

1 files changed, 21 insertions, 0 deletions

diff --git a/libs/minikin/FontFamily.cpp b/libs/minikin/FontFamily.cpp
index f688a33..d2e5867 100644
--- a/libs/minikin/FontFamily.cpp
+++ b/libs/minikin/FontFamily.cpp
@@ -23,6 +23,7 @@
 #include "MinikinInternal.h"
 #include <minikin/MinikinFont.h>
 #include <minikin/AnalyzeStyle.h>
+#include <minikin/CmapCoverage.h>
 #include <minikin/FontFamily.h>
 #include <UniquePtr.h>
 
@@ -128,6 +129,7 @@ void FontFamily::addFont(MinikinFont* typeface, FontStyle style) {
 
 void FontFamily::addFontLocked(MinikinFont* typeface, FontStyle style) {    typeface->RefLocked();
     mFonts.push_back(Font(typeface, style));
+    mCoverageValid = false;
 }
 
 // Compute a matching metric between two styles - 0 is an exact match
@@ -183,4 +185,23 @@ FontStyle FontFamily::getStyle(size_t index) const {
     return mFonts[index].style;
 }
 
+const SparseBitSet* FontFamily::getCoverage() {
+    if (!mCoverageValid) {
+        const FontStyle defaultStyle;
+        MinikinFont* typeface = getClosestMatch(defaultStyle).font;
+        const uint32_t cmapTag = MinikinFont::MakeTag('c', 'm', 'a', 'p');
+        size_t cmapSize = 0;
+        bool ok = typeface->GetTable(cmapTag, NULL, &cmapSize);
+        UniquePtr<uint8_t[]> cmapData(new uint8_t[cmapSize]);
+        ok = typeface->GetTable(cmapTag, cmapData.get(), &cmapSize);
+        CmapCoverage::getCoverage(mCoverage, cmapData.get(), cmapSize);
+#ifdef VERBOSE_DEBUG
+        ALOGD("font coverage length=%d, first ch=%x\n", mCoverage->length(),
+                mCoverage->nextSetBit(0));
+#endif
+        mCoverageValid = true;
+    }
+    return &mCoverage;
+}
+
 }  // namespace android