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Commit 8e7b3b15 authored by Jeff Sharkey's avatar Jeff Sharkey
Browse files

Support optional values in ProcFileReader. 

When new values are added to proc files, we need to handle reading
them from both old and new kernels.  This change supports optionally
reading long values.  Tests to verify.

Bug: 7903145
Change-Id: I9fe250c0486c3cce3cf3d8624f01af01128d1191
parent 1b0e29ae

core/java/com/android/internal/util/ProcFileReader.java

+42 −8
Original line number Diff line number Diff line
@@ -19,6 +19,7 @@ package com.android.internal.util; 
import java.io.Closeable;

import java.io.IOException;

import java.io.InputStream;

import java.net.ProtocolException;

import java.nio.charset.Charsets;



/**
@@ -82,12 +83,15 @@ public class ProcFileReader implements Closeable { 
    }



    /**

     * Find buffer index of next token delimiter, usually space or newline. Will

     * fill buffer as needed.

     * Find buffer index of next token delimiter, usually space or newline.

     * Fills buffer as needed.

     *

     * @return Index of next delimeter, otherwise -1 if no tokens remain on

     *         current line.

     */

    private int nextTokenIndex() throws IOException {

        if (mLineFinished) {

            throw new IOException("no tokens remaining on current line");

            return -1;

        }



        int i = 0;
@@ -105,7 +109,7 @@ public class ProcFileReader implements Closeable { 
            }

        } while (fillBuf() > 0);



        throw new IOException("end of stream while looking for token boundary");

        throw new ProtocolException("End of stream while looking for token boundary");

    }



    /**
@@ -136,7 +140,7 @@ public class ProcFileReader implements Closeable { 
            }

        } while (fillBuf() > 0);



        throw new IOException("end of stream while looking for line boundary");

        throw new ProtocolException("End of stream while looking for line boundary");

    }



    /**
@@ -144,9 +148,11 @@ public class ProcFileReader implements Closeable { 
     */

    public String nextString() throws IOException {

        final int tokenIndex = nextTokenIndex();

        final String s = new String(mBuffer, 0, tokenIndex, Charsets.US_ASCII);

        consumeBuf(tokenIndex + 1);

        return s;

        if (tokenIndex == -1) {

            throw new ProtocolException("Missing required string");

        } else {

            return parseAndConsumeString(tokenIndex);

        }

    }



    /**
@@ -154,6 +160,33 @@ public class ProcFileReader implements Closeable { 
     */

    public long nextLong() throws IOException {

        final int tokenIndex = nextTokenIndex();

        if (tokenIndex == -1) {

            throw new ProtocolException("Missing required long");

        } else {

            return parseAndConsumeLong(tokenIndex);

        }

    }



    /**

     * Parse and return next token as base-10 encoded {@code long}, or return

     * the given default value if no remaining tokens on current line.

     */

    public long nextOptionalLong(long def) throws IOException {

        final int tokenIndex = nextTokenIndex();

        if (tokenIndex == -1) {

            return def;

        } else {

            return parseAndConsumeLong(tokenIndex);

        }

    }



    private String parseAndConsumeString(int tokenIndex) throws IOException {

        final String s = new String(mBuffer, 0, tokenIndex, Charsets.US_ASCII);

        consumeBuf(tokenIndex + 1);

        return s;

    }



    private long parseAndConsumeLong(int tokenIndex) throws IOException {

        final boolean negative = mBuffer[0] == '-';



        // TODO: refactor into something like IntegralToString
@@ -193,6 +226,7 @@ public class ProcFileReader implements Closeable { 
        return (int) value;

    }



    @Override

    public void close() throws IOException {

        mStream.close();

    }

core/tests/coretests/src/com/android/internal/util/ProcFileReaderTest.java

+15 −1
Original line number Diff line number Diff line
@@ -134,7 +134,7 @@ public class ProcFileReaderTest extends AndroidTestCase { 
            fail("somehow read a string value?");

        } catch (IOException e) {

            // expected

            assertTrue(e.getMessage().contains("end of stream"));

            assertTrue(e.getMessage().contains("End of stream"));

        }

    }
@@ -152,6 +152,20 @@ public class ProcFileReaderTest extends AndroidTestCase { 
        }

    }



    public void testOptionalLongs() throws Exception {

        final ProcFileReader reader = buildReader("123 456\n789\n");



        assertEquals(123L, reader.nextLong());

        assertEquals(456L, reader.nextOptionalLong(-1L));

        assertEquals(-1L, reader.nextOptionalLong(-1L));

        assertEquals(-1L, reader.nextOptionalLong(-1L));

        assertEquals(-1L, reader.nextOptionalLong(-1L));

        reader.finishLine();



        assertEquals(789L, reader.nextOptionalLong(-1L));

        assertEquals(-1L, reader.nextOptionalLong(-1L));

    }



    private static ProcFileReader buildReader(String string) throws IOException {

        return buildReader(string, 2048);

    }