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Commit 52e92b8a authored by Jean Chalard's avatar Jean Chalard
Browse files

Simplify handling of steps in DecoderChainSpec 

This is a preliminary refactoring change to improve performance
in dicttool diagnostic tools.

Change-Id: I9a59328af62e336809246be5bebbbf2e154366b3
parent d3a4c513

tools/dicttool/src/com/android/inputmethod/latin/dicttool/BinaryDictOffdeviceUtils.java

+25 −12
Original line number Diff line number Diff line
@@ -45,26 +45,37 @@ public final class BinaryDictOffdeviceUtils { 
    private final static String PREFIX = "dicttool";

    private final static String SUFFIX = ".tmp";



    public final static String COMPRESSION = "compressed";

    public final static String ENCRYPTION = "encrypted";



    private final static int MAX_DECODE_DEPTH = 8;

    private final static int COPY_BUFFER_SIZE = 8192;



    public static class DecoderChainSpec {

        ArrayList<String> mDecoderSpec = new ArrayList<>();

        public final static int COMPRESSION = 1;

        public final static int ENCRYPTION = 2;

        private final static int MAX_DECODE_DEPTH = 4;



        ArrayList<Integer> mDecoderSpec = new ArrayList<>();

        File mFile;



        public DecoderChainSpec addStep(final String stepDescription) {

        public DecoderChainSpec addStep(final int stepDescription) {

            mDecoderSpec.add(stepDescription);

            return this;

        }



        private String getStepDescription(final int step) {

            switch (step) {

            case COMPRESSION:

                return "compression";

            case ENCRYPTION:

                return "encryption";

            default:

                return "unknown";

            }

        }



        public String describeChain() {

            final StringBuilder s = new StringBuilder("raw");

            for (final String step : mDecoderSpec) {

            for (final int step : mDecoderSpec) {

                s.append(" > ");

                s.append(step);

                s.append(getStepDescription(step));

            }

            return s.toString();

        }
@@ -91,11 +102,13 @@ public final class BinaryDictOffdeviceUtils { 
    private static DecoderChainSpec getRawDictionaryOrNullInternal(

            final DecoderChainSpec spec, final File src, final int depth) {

        // Unfortunately the decoding scheme we use can consider any data to be encrypted

        // and will product some output, meaning it's not possible to reliably detect encrypted

        // and will produce some output, meaning it's not possible to reliably detect encrypted

        // data. Thus, some non-dictionary files (especially small) ones may successfully decrypt

        // over and over, ending in a stack overflow. Hence we limit the depth at which we try

        // decoding the file.

        if (depth > MAX_DECODE_DEPTH) return null;

        if (depth > DecoderChainSpec.MAX_DECODE_DEPTH) {

            return null;

        }

        if (BinaryDictDecoderUtils.isBinaryDictionary(src)

                || CombinedInputOutput.isCombinedDictionary(src.getAbsolutePath())) {

            spec.mFile = src;
@@ -107,7 +120,7 @@ public final class BinaryDictOffdeviceUtils { 
            final DecoderChainSpec newSpec =

                    getRawDictionaryOrNullInternal(spec, uncompressedFile, depth + 1);

            if (null == newSpec) return null;

            return newSpec.addStep(COMPRESSION);

            return newSpec.addStep(DecoderChainSpec.COMPRESSION);

        }

        // It's not a compressed either - try to see if it's crypted.

        final File decryptedFile = tryGetDecryptedFile(src);
@@ -115,7 +128,7 @@ public final class BinaryDictOffdeviceUtils { 
            final DecoderChainSpec newSpec =

                    getRawDictionaryOrNullInternal(spec, decryptedFile, depth + 1);

            if (null == newSpec) return null;

            return newSpec.addStep(ENCRYPTION);

            return newSpec.addStep(DecoderChainSpec.ENCRYPTION);

        }

        return null;

    }

tools/dicttool/tests/com/android/inputmethod/latin/dicttool/BinaryDictOffdeviceUtilsTests.java

+3 −2
Original line number Diff line number Diff line
@@ -78,8 +78,9 @@ public class BinaryDictOffdeviceUtilsTests extends TestCase { 
        // Test for an actually compressed dictionary and its contents

        final BinaryDictOffdeviceUtils.DecoderChainSpec decodeSpec =

                BinaryDictOffdeviceUtils.getRawDictionaryOrNull(dst);

        for (final String step : decodeSpec.mDecoderSpec) {

            assertEquals("Wrong decode spec", BinaryDictOffdeviceUtils.COMPRESSION, step);

        for (final int step : decodeSpec.mDecoderSpec) {

            assertEquals("Wrong decode spec",

                    BinaryDictOffdeviceUtils.DecoderChainSpec.COMPRESSION, step);

        }

        assertEquals("Wrong decode spec", 3, decodeSpec.mDecoderSpec.size());

        final DictDecoder dictDecoder = BinaryDictIOUtils.getDictDecoder(decodeSpec.mFile, 0,