Revert of Experimental parsing expression grammar (PEG) template library (patchset #8 id:140001 of https://codereview.chromium.org/2271743002/ )

Reason for revert:
G3 roll & Msan woes.

Original issue's description:
> Experimental parsing expression grammar (PEG) template library
>
>
> BUG=skia:
> GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=2271743002
>
> Committed: https://skia.googlesource.com/skia/+/9d08cbc8c6131ff61a1e71cc5c8cf27841d62b42

TBR=mtklein@google.com,bungeman@google.com,reed@google.com
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=skia:

Review-Url: https://codereview.chromium.org/2275943004

4 files changed, 0 insertions, 547 deletions

diff --git a/BUILD.gn b/BUILD.gn
index 6774890d1d..8bc4505d65 100644
--- a/BUILD.gn
+++ b/BUILD.gn
@@ -640,7 +640,6 @@ if (skia_enable_tools) {
           rebase_path("tests/skia_test.cpp"),  # alternate main
         ]
     deps = [
-      ":experimental_svg_model",
       ":flags",
       ":gpu_tool_utils",
       ":skia",
diff --git a/experimental/svg/model/SkPEG.h b/experimental/svg/model/SkPEG.h
deleted file mode 100644
index 886852019e..0000000000
--- a/experimental/svg/model/SkPEG.h
+++ /dev/null
@@ -1,244 +0,0 @@
-/*
- * Copyright 2016 Google Inc.
- *
- * Use of this source code is governed by a BSD-style license that can be
- * found in the LICENSE file.
- */
-
-#ifndef SkPEG_DEFINED
-#define SkPEG_DEFINED
-
-#include "SkTDArray.h"
-#include "SkTLazy.h"
-
-namespace skpeg {
-
-/**
- *  The result of an expression match attempt.
- *
- *  If the match was successful, |fNext| points to the next unconsumed character in the
- *  input string, and |fValue| holds an (arbitrarily nested) match result value.
- *
- *  Otherwise, |fNext| is nullptr and |fValue| is uninitialized.
- */
-template <typename V>
-struct MatchResult {
-    MatchResult(std::nullptr_t) : fNext(nullptr) {}
-    MatchResult(const char* next, const V& v) : fNext(next), fValue(&v) {}
-
-    operator bool() const {
-        SkASSERT(fValue.isValid() == SkToBool(fNext));
-        return SkToBool(fNext);
-    }
-
-    const V& operator* () const { return *fValue.get(); }
-    const V* operator->() const { return  fValue.get(); }
-
-    const char* fNext;
-    SkTLazy<V>  fValue;
-};
-
-/**
- * Optional operator (e?).  Always succeeds.
- *
- * If e also matches, then the result of e::Match() is stored in |fValue|.
- * Otherwise, |fValue| is uninitialized.
- *
- */
-template <typename E>
-struct Opt {
-    struct V {
-        V(const typename E::V* v) : fValue(v) {}
-
-        SkTLazy<typename E::V> fValue;
-    };
-    using MatchT = MatchResult<V>;
-
-    static MatchT Match(const char* in) {
-        const auto m = E::Match(in);
-        return m ? MatchT(m.fNext, V(m.fValue.get()))
-                 : MatchT(in, nullptr);
-    }
-};
-
-/**
- * Helper for selecting the value type of the n-th expression type in the list.
- */
-template <size_t, typename... Es> struct SelectV;
-
-template <typename E, typename... Es>
-struct SelectV<0, E, Es...> {
-    using V = typename E::V;
-};
-
-template <size_t idx, typename E, typename... Es>
-struct SelectV<idx, E, Es...> {
-    using V = typename SelectV<idx - 1, Es...>::V;
-};
-
-/**
- * Sequence operator (e0 e1...).
- *
- * Succeeds when all expressions match, in sequence.  The subexpression match
- * results can be accessed via get<INDEX>() -- where get<0> returns the value
- * of the first expression, and so on.
- *
- */
-template <typename... E> struct Seq;
-
-template <>
-struct Seq<> {
-    struct V {};
-    using MatchT = MatchResult<V>;
-
-    static MatchT Match(const char* in) {
-        return MatchT(in, V());
-    }
-};
-
-template <typename E, typename... Es>
-struct Seq<E, Es...> {
-    class V {
-    public:
-        V(const typename E::V& head, const typename Seq<Es...>::V& tail)
-            : fHeadV(head), fTailV(tail) {}
-
-        template <size_t idx, typename std::enable_if<idx == 0, bool>::type = 0>
-        const typename E::V& get() const {
-            return fHeadV;
-        }
-
-        template <size_t idx, typename std::enable_if<idx != 0, bool>::type = 0>
-        const typename SelectV<idx, E, Es...>::V& get() const {
-            return fTailV.template get<idx - 1>();
-        }
-
-    private:
-        typename E::V          fHeadV;
-        typename Seq<Es...>::V fTailV;
-    };
-    using MatchT = MatchResult<V>;
-
-    static MatchT Match(const char* in) {
-        const auto headMatch = E::Match(in);
-        if (!headMatch) {
-            return nullptr;
-        }
-
-        const auto tailMatch = Seq<Es...>::Match(headMatch.fNext);
-        return tailMatch ? MatchT(tailMatch.fNext, V(*headMatch, *tailMatch))
-                         : nullptr;
-    }
-};
-
-/**
- * Ordered choice operator (e1|e2).
- *
- * Succeeds when either e1 or e2 match (e1 is tried first, then e2).
- *
- * The (optional) match results are stored in |v1|, |v2|.
- *
- */
-template <typename E1, typename E2>
-struct Choice {
-    struct V {
-        V (const typename E1::V* v1, const typename E2::V* v2) : v1(v1), v2(v2)
-        {
-            SkASSERT(!v1 || !v2);
-        }
-
-        SkTLazy<typename E1::V> v1;
-        SkTLazy<typename E2::V> v2;
-    };
-    using MatchT = MatchResult<V>;
-
-    static MatchT Match(const char* in) {
-        if (const auto m1 = E1::Match(in)) {
-            return MatchT(m1.fNext, V(m1.fValue.get(), nullptr));
-        }
-        if (const auto m2 = E2::Match(in)) {
-            return MatchT(m2.fNext, V(nullptr, m2.fValue.get()));
-        }
-        return nullptr;
-    }
-};
-
-/**
- * Zero-or-more operator (e*).  Always succeeds.
- *
- * Matches e greedily, and stores the match results in |fValues|.
- *
- */
-template <typename E>
-struct Any {
-    struct V {
-        V(SkTDArray<typename E::V>&& vs) : fValues(vs) {}
-
-        SkTDArray<typename E::V> fValues;
-    };
-    using MatchT = MatchResult<V>;
-
-    static MatchT Match(const char* in) {
-        SkTDArray<typename E::V> values;
-        while (const auto m = E::Match(in)) {
-            in = m.fNext;
-            *values.append() = *m;
-        }
-        return MatchT(in, std::move(values));
-    }
-};
-
-/**
- * One-or-more operator (e+).
- *
- * Same as zero-or-more, except it fails if e doesn't match at least once.
- *
- */
-template <typename E>
-using Some = Seq<E, Any<E>>;
-
-/**
- * End-of-string atom.  Matches \0.
- */
-struct EOS {
-    struct V {};
-    using MatchT = MatchResult<V>;
-
-    static MatchT Match(const char* in) {
-        return (*in != '\0') ? nullptr : MatchT(in, V());
-    }
-};
-
-
-/**
- * Literal atom.  Matches a list of char literals.
- */
-template <char... Cs> struct LIT;
-
-template <>
-struct LIT<> {
-    struct V {};
-    using MatchT = MatchResult<V>;
-
-    static MatchT Match(const char* in) {
-        return MatchT(in, V());
-    }
-};
-
-template <char C, char... Cs>
-struct LIT<C, Cs...> {
-    struct V {};
-    using MatchT = MatchResult<V>;
-
-    static MatchT Match(const char* in) {
-        if (*in != C) {
-            return nullptr;
-        }
-        const auto m = LIT<Cs...>::Match(in + 1);
-        return m ? MatchT(m.fNext, V()) : nullptr;
-    }
-};
-
-} // skpeg ns
-
-#endif // SkPEG_DEFINED
diff --git a/gyp/svg.gyp b/gyp/svg.gyp
index 1160b94d97..158a3992e3 100644
--- a/gyp/svg.gyp
+++ b/gyp/svg.gyp
@@ -78,8 +78,6 @@
         '../experimental/svg/model/SkSVGTypes.h',
         '../experimental/svg/model/SkSVGValue.h',
         '../experimental/svg/model/SkSVGValue.cpp',
-
-        '../experimental/svg/model/SkPEG.h',
       ],
       'direct_dependent_settings': {
         'include_dirs': [
diff --git a/tests/SkPEGTest.cpp b/tests/SkPEGTest.cpp
deleted file mode 100644
index 68a47776e8..0000000000
--- a/tests/SkPEGTest.cpp
+++ /dev/null
@@ -1,300 +0,0 @@
-/*
- * Copyright 2016 Google Inc.
- *
- * Use of this source code is governed by a BSD-style license that can be
- * found in the LICENSE file.
- */
-
-#include "SkPEG.h"
-#include "Test.h"
-
-using namespace skpeg;
-
-namespace {
-
-struct Alpha {
-    using V = char;
-    using MatchT = MatchResult<V>;
-
-    static MatchT Match(const char* in) {
-        static constexpr unsigned kAlphaRange = 'z' - 'a';
-        return static_cast<unsigned>(*in - 'a') <= kAlphaRange
-            || static_cast<unsigned>(*in - 'A') <= kAlphaRange
-            ? MatchT(in + 1, *in)
-            : nullptr;
-    }
-};
-
-struct Digit {
-    using V = uint8_t;
-    using MatchT = MatchResult<V>;
-
-    static MatchT Match(const char* in) {
-        static constexpr unsigned kDigitRange = '9' - '0';
-        return static_cast<unsigned>(*in - '0') <= kDigitRange
-            ? MatchT(in + 1, SkTo<uint8_t>(*in - '0'))
-            : nullptr;
-    }
-};
-
-void test_EOS(skiatest::Reporter* r) {
-    static const struct {
-        const char* fInput;
-        bool        fMatch;
-    } gTests[] = {
-        { ""   , true  },
-        { " "  , false },
-        { "\0" , true  },
-        { "foo", false },
-    };
-
-    for (size_t i = 0; i < SK_ARRAY_COUNT(gTests); ++i) {
-        const auto match = EOS::Match(gTests[i].fInput);
-        REPORTER_ASSERT(r, match == gTests[i].fMatch);
-        REPORTER_ASSERT(r, match.fNext == (match ? gTests[i].fInput : nullptr));
-    }
-}
-
-void test_LIT(skiatest::Reporter* r) {
-    static const struct {
-        const char* fInput;
-        bool        fMatch;
-    } gTests[] = {
-        { ""  , false },
-        { " " , false },
-        { "x" , false },
-        { "X" , true  },
-        { "xX", false },
-        { "Xx", true  },
-    };
-
-    for (size_t i = 0; i < SK_ARRAY_COUNT(gTests); ++i) {
-        const auto match = LIT<'X'>::Match(gTests[i].fInput);
-        REPORTER_ASSERT(r, match == gTests[i].fMatch);
-        REPORTER_ASSERT(r, match.fNext == (match ? gTests[i].fInput + 1 : nullptr));
-    }
-
-    REPORTER_ASSERT(r, !(LIT<'F', 'o', 'o'>::Match("")));
-    REPORTER_ASSERT(r, !(LIT<'F', 'o', 'o'>::Match("Fo")));
-    REPORTER_ASSERT(r, !(LIT<'F', 'o', 'o'>::Match("FoO")));
-    REPORTER_ASSERT(r,  (LIT<'F', 'o', 'o'>::Match("Foo")));
-    REPORTER_ASSERT(r,  (LIT<'F', 'o', 'o'>::Match("Foobar")));
-}
-
-void test_Alpha(skiatest::Reporter* r) {
-    static const struct {
-        const char* fInput;
-        bool        fMatch;
-        char        fMatchValue;
-    } gTests[] = {
-        { ""  , false,  0  },
-        { "\r", false,  0  },
-        { "\n", false,  0  },
-        { "\t", false,  0  },
-        { "0" , false,  0  },
-        { "9" , false,  0  },
-        { "a" , true , 'a' },
-        { "a" , true , 'a' },
-        { "z" , true , 'z' },
-        { "A" , true , 'A' },
-        { "Z" , true , 'Z' },
-        { "az", true , 'a' },
-        { "a0", true , 'a' },
-        { "0a", false,  0  },
-    };
-
-    for (size_t i = 0; i < SK_ARRAY_COUNT(gTests); ++i) {
-        const auto match = Alpha::Match(gTests[i].fInput);
-        REPORTER_ASSERT(r, match == gTests[i].fMatch);
-        REPORTER_ASSERT(r, match.fNext == (match ? gTests[i].fInput + 1 : nullptr));
-        if (match) {
-            REPORTER_ASSERT(r, *match == gTests[i].fMatchValue);
-        }
-    }
-}
-
-void test_Digit(skiatest::Reporter* r) {
-    static const struct {
-        const char* fInput;
-        bool        fMatch;
-        uint8_t     fMatchValue;
-    } gTests[] = {
-        { ""   , false, 0 },
-        { "/"  , false, 0 },
-        { ":"  , false, 0 },
-        { "x"  , false, 0 },
-        { "x0" , false, 0 },
-        { "0"  , true , 0 },
-        { "1x" , true , 1 },
-        { "9 a", true , 9 },
-    };
-
-    for (size_t i = 0; i < SK_ARRAY_COUNT(gTests); ++i) {
-        const auto match = Digit::Match(gTests[i].fInput);
-        REPORTER_ASSERT(r, match == gTests[i].fMatch);
-        REPORTER_ASSERT(r, match.fNext == (match ? gTests[i].fInput + 1 : nullptr));
-        if (match) {
-            REPORTER_ASSERT(r, *match == gTests[i].fMatchValue);
-        }
-    }
-}
-
-void test_Opt(skiatest::Reporter* r) {
-    static const struct {
-        const char* fInput;
-        bool        fMatch;
-    } gTests[] = {
-        { ""       , false },
-        { "fo"     , false },
-        { " foo"   , false },
-        { "foo"    , true },
-        { "foobar" , true },
-    };
-
-    for (size_t i = 0; i < SK_ARRAY_COUNT(gTests); ++i) {
-        const auto m = Opt<LIT<'f', 'o', 'o'>>::Match(gTests[i].fInput);
-        REPORTER_ASSERT(r, m);
-        REPORTER_ASSERT(r, m->fValue.isValid() == gTests[i].fMatch);
-    }
-}
-
-void test_Seq(skiatest::Reporter* r) {
-    REPORTER_ASSERT(r,  (Seq<LIT<'X'>, EOS>::Match("X")));
-    REPORTER_ASSERT(r, !(Seq<LIT<'X'>, EOS>::Match("x")));
-    REPORTER_ASSERT(r, !(Seq<LIT<'X'>, EOS>::Match("xX")));
-    REPORTER_ASSERT(r, !(Seq<LIT<'X'>, EOS>::Match("XX")));
-    REPORTER_ASSERT(r,  (Seq<LIT<'X'>, Seq<LIT<'X'>, EOS>>::Match("XX")));
-    REPORTER_ASSERT(r,  (Seq<LIT<'X'>, Seq<LIT<'X'>, EOS>>::Match("XX")));
-
-    REPORTER_ASSERT(r, !(Seq<LIT<'F', 'o', 'o'>, EOS>::Match("FooBar")));
-    REPORTER_ASSERT(r,  (Seq<LIT<'F', 'o', 'o'>, EOS>::Match("Foo")));
-
-    {
-        const auto m = Seq<LIT<'x'>, Digit>::Match("x5");
-        REPORTER_ASSERT(r, m);
-        REPORTER_ASSERT(r, m->get<1>() == 5);
-    }
-    {
-        const auto m = Seq<Digit, Digit>::Match("42");
-        REPORTER_ASSERT(r, m);
-        REPORTER_ASSERT(r, m->get<0>() == 4);
-        REPORTER_ASSERT(r, m->get<1>() == 2);
-    }
-}
-
-void test_Choice(skiatest::Reporter* r) {
-    REPORTER_ASSERT(r, !(Choice<Digit,Alpha>::Match("")));
-    REPORTER_ASSERT(r, !(Choice<Digit,Alpha>::Match("\t")));
-    REPORTER_ASSERT(r, !(Choice<Digit,Alpha>::Match(" ")));
-    REPORTER_ASSERT(r,  (Choice<Digit,Alpha>::Match("a")));
-    REPORTER_ASSERT(r,  (Choice<Digit,Alpha>::Match("3")));
-    REPORTER_ASSERT(r,  (Choice<Digit,Alpha>::Match("a ")));
-    REPORTER_ASSERT(r,  (Choice<Digit,Alpha>::Match("3 ")));
-    REPORTER_ASSERT(r, !(Choice<Digit,Alpha>::Match(" a ")));
-    REPORTER_ASSERT(r, !(Choice<Digit,Alpha>::Match(" 3 ")));
-
-    {
-        const auto m = Choice<Alpha, Digit>::Match("x");
-        REPORTER_ASSERT(r,  m);
-        REPORTER_ASSERT(r,  m->v1.isValid());
-        REPORTER_ASSERT(r, !m->v2.isValid());
-        REPORTER_ASSERT(r, *m->v1.get() == 'x');
-    }
-
-    {
-        const auto m = Choice<Alpha, Digit>::Match("7");
-        REPORTER_ASSERT(r,  m);
-        REPORTER_ASSERT(r, !m->v1.isValid());
-        REPORTER_ASSERT(r,  m->v2.isValid());
-        REPORTER_ASSERT(r, *m->v2.get() == 7);
-    }
-}
-
-void test_AnySome(skiatest::Reporter* r) {
-    static const struct {
-        const char* fInput;
-        int         fCount;
-    } gTests[] = {
-        { ""      , 0 },
-        { "fo"    , 0 },
-        { "Foo"   , 0 },
-        { "foo"   , 1 },
-        { "foofoo", 2 },
-    };
-
-    for (size_t i = 0; i < SK_ARRAY_COUNT(gTests); ++i) {
-        const auto matchAny = Any<LIT<'f', 'o', 'o'>>::Match(gTests[i].fInput);
-        REPORTER_ASSERT(r, matchAny);
-        REPORTER_ASSERT(r, matchAny->fValues.count() == gTests[i].fCount);
-
-        const auto matchSome = Some<LIT<'f', 'o', 'o'>>::Match(gTests[i].fInput);
-        REPORTER_ASSERT(r,  matchSome == (gTests[i].fCount > 0));
-        REPORTER_ASSERT(r, !matchSome ||
-                            matchSome->get<1>().fValues.count() == gTests[i].fCount - 1);
-    }
-
-    {
-        const auto m = Any<Digit>::Match("0123456789foo");
-        REPORTER_ASSERT(r, m);
-        REPORTER_ASSERT(r, m->fValues.count() == 10);
-        for (int i = 0; i < m->fValues.count(); ++i) {
-            REPORTER_ASSERT(r, m->fValues[i] == i);
-        }
-    }
-}
-
-void test_Complex(skiatest::Reporter* r) {
-    // [0-9]+(,[0-9]+)?$
-    using P0 =
-        Seq<
-          Some<Digit>,
-          Opt<Seq<
-            LIT<','>,
-            Some<Digit>>>,
-          EOS>;
-
-    REPORTER_ASSERT(r, !P0::Match(""));
-    REPORTER_ASSERT(r, !P0::Match(","));
-    REPORTER_ASSERT(r, !P0::Match("1,"));
-    REPORTER_ASSERT(r, !P0::Match(",1"));
-    REPORTER_ASSERT(r,  P0::Match("1"));
-    REPORTER_ASSERT(r,  P0::Match("1,2"));
-    REPORTER_ASSERT(r, !P0::Match("1,2 "));
-    REPORTER_ASSERT(r,  P0::Match("123,456"));
-
-    // [ ]*[Ff]oo([Bb]ar)+[Bb]az[ ]*$
-    using P1 =
-        Seq<
-          Any<LIT<' '>>,
-          Choice<LIT<'F'>, LIT<'f'>>,
-          LIT<'o', 'o'>,
-          Some<Seq<
-            Choice<LIT<'B'>, LIT<'b'>>,
-            LIT<'a', 'r'>>>,
-          Choice<LIT<'B'>, LIT<'b'>>,
-          LIT<'a', 'z'>,
-          Any<LIT<' '>>,
-          EOS>;
-
-    REPORTER_ASSERT(r, !P1::Match(""));
-    REPORTER_ASSERT(r, !P1::Match("FooBar"));
-    REPORTER_ASSERT(r, !P1::Match("FooBaz"));
-    REPORTER_ASSERT(r,  P1::Match("FooBarBaz"));
-    REPORTER_ASSERT(r,  P1::Match("foobarbaz"));
-    REPORTER_ASSERT(r,  P1::Match("  FooBarbaz     "));
-    REPORTER_ASSERT(r,  P1::Match(" FooBarbarbarBaz "));
-}
-
-} // anonymous ns
-
-DEF_TEST(SkPEG, r) {
-    test_EOS(r);
-    test_LIT(r);
-    test_Alpha(r);
-    test_Digit(r);
-    test_Opt(r);
-    test_Seq(r);
-    test_Choice(r);
-    test_AnySome(r);
-    test_Complex(r);
-}