Bug 1291483 part 2: Use UniquePtr/MakeUnique more thoroughly in chain-of-custody for gfxFont::mVerticalMetrics. r=jfkthame
authorDaniel Holbert <dholbert@cs.stanford.edu>
Thu, 09 Mar 2017 16:38:58 -0800
changeset 347043 2f96904d7b3ae012d17e25458f460f8de6cd5978
parent 347042 08753d5d8f1a05dedce9f91887a1e5426f35f8c0
child 347044 7a7d6e9b8329d2806f985836c201a69503e9b24e
push id31490
push usercbook@mozilla.com
push dateMon, 13 Mar 2017 14:19:54 +0000
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Bug 1291483 part 2: Use UniquePtr/MakeUnique more thoroughly in chain-of-custody for gfxFont::mVerticalMetrics. r=jfkthame This member-var has type 'UniquePtr', but (up until this patch) its value is set up using "new" and raw pointers. This patch improves that codepath by using UniquePtr & MakeUnique, for stronger ownership guarantees. MozReview-Commit-ID: KWZVpvr9bYj
--- a/gfx/thebes/gfxFont.cpp
+++ b/gfx/thebes/gfxFont.cpp
@@ -3637,27 +3637,27 @@ gfxFont::SanitizeMetrics(gfxFont::Metric
 // fail, as we've already decided this is a valid font. We do not have the
 // option of marking it invalid (as can happen if we're unable to read
 // horizontal metrics), because that could break a font that we're already
 // using for horizontal text.
 // So we will synthesize *something* usable here even if there aren't any of the
 // usual font tables (which can happen in the case of a legacy bitmap or Type1
 // font for which the platform-specific backend used platform APIs instead of
 // sfnt tables to create the horizontal metrics).
-const gfxFont::Metrics*
+UniquePtr<const gfxFont::Metrics>
     const uint32_t kHheaTableTag = TRUETYPE_TAG('h','h','e','a');
     const uint32_t kVheaTableTag = TRUETYPE_TAG('v','h','e','a');
     const uint32_t kPostTableTag = TRUETYPE_TAG('p','o','s','t');
     const uint32_t kOS_2TableTag = TRUETYPE_TAG('O','S','/','2');
     uint32_t len;
-    Metrics* metrics = new Metrics;
-    ::memset(metrics, 0, sizeof(Metrics));
+    UniquePtr<Metrics> metrics = MakeUnique<Metrics>();
+    ::memset(metrics.get(), 0, sizeof(Metrics));
     // Some basic defaults, in case the font lacks any real metrics tables.
     // TODO: consider what rounding (if any) we should apply to these.
     metrics->emHeight = GetAdjustedSize();
     metrics->emAscent = metrics->emHeight / 2;
     metrics->emDescent = metrics->emHeight - metrics->emAscent;
     metrics->maxAscent = metrics->emAscent;
@@ -3792,17 +3792,17 @@ gfxFont::CreateVerticalMetrics()
     // Somewhat arbitrary values for now, subject to future refinement...
     metrics->spaceWidth = metrics->aveCharWidth;
     metrics->zeroOrAveCharWidth = metrics->aveCharWidth;
     metrics->maxHeight = metrics->maxAscent + metrics->maxDescent;
     metrics->xHeight = metrics->emHeight / 2;
     metrics->capHeight = metrics->maxAscent;
-    return metrics;
+    return Move(metrics);
 gfxFont::SynthesizeSpaceWidth(uint32_t aCh)
     // return an appropriate width for various Unicode space characters
     // that we "fake" if they're not actually present in the font;
     // returns negative value if the char is not a known space.
--- a/gfx/thebes/gfxFont.h
+++ b/gfx/thebes/gfxFont.h
@@ -1546,17 +1546,17 @@ public:
     const Metrics& GetMetrics(Orientation aOrientation)
         if (aOrientation == eHorizontal) {
             return GetHorizontalMetrics();
         if (!mVerticalMetrics) {
-            mVerticalMetrics.reset(CreateVerticalMetrics());
+            mVerticalMetrics = CreateVerticalMetrics();
         return *mVerticalMetrics;
      * We let layout specify spacing on either side of any
      * character. We need to specify both before and after
      * spacing so that substring measurement can do the right things.
@@ -1863,17 +1863,17 @@ public:
      * Return the reference cairo_t object from aDT.
     static cairo_t* RefCairo(mozilla::gfx::DrawTarget* aDT);
     virtual const Metrics& GetHorizontalMetrics() = 0;
-    const Metrics* CreateVerticalMetrics();
+    mozilla::UniquePtr<const Metrics> CreateVerticalMetrics();
     // Output a single glyph at *aPt, which is updated by the glyph's advance.
     // Normal glyphs are simply accumulated in aBuffer until it is full and
     // gets flushed, but SVG or color-font glyphs will instead be rendered
     // directly to the destination (found from the buffer's parameters).
     void DrawOneGlyph(uint32_t           aGlyphID,
                       double             aAdvance,
                       gfxPoint          *aPt,