From 31c61e74156730f04eef641bfb69b9ee94b62fbd Mon Sep 17 00:00:00 2001 From: Matthias Andreas Benkard Date: Thu, 16 Dec 2021 20:06:39 +0100 Subject: Add Signature and Variant types. Change-Id: I3579fb8745d7b021af7534d2f0c5a0aa6ce54518 --- src/main/java/eu/mulk/jgvariant/core/Decoder.java | 58 +++-------- .../java/eu/mulk/jgvariant/core/Signature.java | 113 +++++++++++++++++++++ src/main/java/eu/mulk/jgvariant/core/Variant.java | 25 +++++ 3 files changed, 154 insertions(+), 42 deletions(-) create mode 100644 src/main/java/eu/mulk/jgvariant/core/Signature.java create mode 100644 src/main/java/eu/mulk/jgvariant/core/Variant.java (limited to 'src/main') diff --git a/src/main/java/eu/mulk/jgvariant/core/Decoder.java b/src/main/java/eu/mulk/jgvariant/core/Decoder.java index 9833998..389ae85 100644 --- a/src/main/java/eu/mulk/jgvariant/core/Decoder.java +++ b/src/main/java/eu/mulk/jgvariant/core/Decoder.java @@ -7,7 +7,7 @@ import java.lang.reflect.RecordComponent; import java.nio.ByteBuffer; import java.nio.ByteOrder; import java.nio.charset.Charset; -import java.nio.charset.StandardCharsets; +import java.text.ParseException; import java.util.ArrayList; import java.util.Arrays; import java.util.List; @@ -47,8 +47,11 @@ public abstract class Decoder { private Decoder() {} /** + * Decodes a {@link ByteBuffer} holding a serialized GVariant into a value of type {@code T}. + * * @throws java.nio.BufferUnderflowException if the byte buffer is shorter than the requested * data. + * @throws IllegalArgumentException if the serialized GVariant is ill-formed */ public abstract T decode(ByteBuffer byteSlice); @@ -156,7 +159,7 @@ public abstract class Decoder { * * @return a new {@link Decoder}. */ - public static Decoder ofVariant() { + public static Decoder ofVariant() { return new VariantDecoder(); } @@ -464,7 +467,7 @@ public abstract class Decoder { } } - private static class VariantDecoder extends Decoder { + private static class VariantDecoder extends Decoder { @Override public byte alignment() { @@ -478,55 +481,26 @@ public abstract class Decoder { } @Override - public Object decode(ByteBuffer byteSlice) { + public Variant decode(ByteBuffer byteSlice) { for (int i = byteSlice.limit() - 1; i >= 0; --i) { if (byteSlice.get(i) != 0) { continue; } - var data = byteSlice.slice(0, i); - var signature = byteSlice.slice(i + 1, byteSlice.limit() - (i + 1)); - - Decoder decoder = parseSignature(signature); - return decoder.decode(data); - } + var dataBytes = byteSlice.slice(0, i); + var signatureBytes = byteSlice.slice(i + 1, byteSlice.limit() - (i + 1)); - throw new IllegalArgumentException("variant signature not found"); - } - - private static Decoder parseSignature(ByteBuffer signature) { - char c = (char) signature.get(); - return switch (c) { - case 'b' -> Decoder.ofBoolean(); - case 'y' -> Decoder.ofByte(); - case 'n', 'q' -> Decoder.ofShort(); - case 'i', 'u' -> Decoder.ofInt(); - case 'x', 't' -> Decoder.ofLong(); - case 'd' -> Decoder.ofDouble(); - case 's', 'o', 'g' -> Decoder.ofString(StandardCharsets.UTF_8); - case 'v' -> Decoder.ofVariant(); - case 'm' -> Decoder.ofMaybe(parseSignature(signature)); - case 'a' -> Decoder.ofArray(parseSignature(signature)); - case '(', '{' -> Decoder.ofStructure(parseTupleTypes(signature).toArray(new Decoder[0])); - default -> throw new IllegalArgumentException( - String.format("encountered unknown signature byte '%c'", c)); - }; - } - - private static List> parseTupleTypes(ByteBuffer signature) { - List> decoders = new ArrayList<>(); - - while (true) { - char c = (char) signature.get(signature.position()); - if (c == ')' || c == '}') { - signature.get(); - break; + Signature signature; + try { + signature = Signature.parse(signatureBytes); + } catch (ParseException e) { + throw new IllegalArgumentException(e); } - decoders.add(parseSignature(signature)); + return new Variant(signature, signature.decoder().decode(dataBytes)); } - return decoders; + throw new IllegalArgumentException("variant signature not found"); } } diff --git a/src/main/java/eu/mulk/jgvariant/core/Signature.java b/src/main/java/eu/mulk/jgvariant/core/Signature.java new file mode 100644 index 0000000..bb03b94 --- /dev/null +++ b/src/main/java/eu/mulk/jgvariant/core/Signature.java @@ -0,0 +1,113 @@ +package eu.mulk.jgvariant.core; + +import java.nio.ByteBuffer; +import java.nio.charset.StandardCharsets; +import java.text.ParseException; +import java.util.ArrayList; +import java.util.List; +import java.util.Objects; + +/** + * A GVariant signature string. + * + *

Describes a type in the GVariant type system. The type can be arbitrarily complex. + * + *

Examples + * + *

+ *
{@code "i"} + *
a single 32-bit integer + *
{@code "ai"} + *
an array of 32-bit integers + *
{@code "(bbb(sai))"} + *
a record consisting of three booleans and a nested record, which consists of a string and + * an array of 32-bit integers + *
+ */ +public final class Signature { + + private final String signatureString; + private final Decoder decoder; + + Signature(ByteBuffer signatureBytes) throws ParseException { + this.decoder = parseSignature(signatureBytes); + + signatureBytes.rewind(); + this.signatureString = StandardCharsets.US_ASCII.decode(signatureBytes).toString(); + } + + static Signature parse(ByteBuffer signatureBytes) throws ParseException { + return new Signature(signatureBytes); + } + + static Signature parse(String signatureString) throws ParseException { + var signatureBytes = ByteBuffer.wrap(signatureString.getBytes(StandardCharsets.US_ASCII)); + return parse(signatureBytes); + } + + /** + * Returns a {@link Decoder} that can decode values conforming to this signature. + * + * @return a {@link Decoder} for this signature + */ + @SuppressWarnings("unchecked") + Decoder decoder() { + return (Decoder) decoder; + } + + /** + * Returns the signature formatted as a GVariant signature string. + * + * @return a GVariant signature string. + */ + @Override + public String toString() { + return signatureString; + } + + @Override + public boolean equals(Object o) { + return (o instanceof Signature signature) + && Objects.equals(signatureString, signature.signatureString); + } + + @Override + public int hashCode() { + return Objects.hash(signatureString); + } + + private static Decoder parseSignature(ByteBuffer signature) throws ParseException { + char c = (char) signature.get(); + return switch (c) { + case 'b' -> Decoder.ofBoolean(); + case 'y' -> Decoder.ofByte(); + case 'n', 'q' -> Decoder.ofShort(); + case 'i', 'u' -> Decoder.ofInt(); + case 'x', 't' -> Decoder.ofLong(); + case 'd' -> Decoder.ofDouble(); + case 's', 'o', 'g' -> Decoder.ofString(StandardCharsets.UTF_8); + case 'v' -> Decoder.ofVariant(); + case 'm' -> Decoder.ofMaybe(parseSignature(signature)); + case 'a' -> Decoder.ofArray(parseSignature(signature)); + case '(', '{' -> Decoder.ofStructure(parseTupleTypes(signature).toArray(new Decoder[0])); + default -> throw new ParseException( + String.format("encountered unknown signature byte '%c'", c), signature.position()); + }; + } + + private static List> parseTupleTypes(ByteBuffer signature) throws ParseException { + List> decoders = new ArrayList<>(); + + while (true) { + char c = (char) signature.get(signature.position()); + if (c == ')' || c == '}') { + signature.get(); + break; + } + + decoders.add(parseSignature(signature)); + } + + return decoders; + } +} diff --git a/src/main/java/eu/mulk/jgvariant/core/Variant.java b/src/main/java/eu/mulk/jgvariant/core/Variant.java new file mode 100644 index 0000000..e2b4b68 --- /dev/null +++ b/src/main/java/eu/mulk/jgvariant/core/Variant.java @@ -0,0 +1,25 @@ +package eu.mulk.jgvariant.core; + +/** + * A dynamically typed GVariant value carrying a {@link Signature} describing its type. + * + *

{@link #value()} can be of one of the following types: + * + *

    + *
  • {@link Boolean} + *
  • {@link Byte} + *
  • {@link Short} + *
  • {@link Integer} + *
  • {@link Long} + *
  • {@link String} + *
  • {@link java.util.Optional} (a GVariant {@code Maybe} type) + *
  • {@link java.util.List} (a GVariant array) + *
  • {@link Object[]} (a GVariant structure) + *
+ * + * @param signature the signature describing the type of the value. + * @param value the value itself; one of {@link Boolean}, {@link Byte}, {@link Short}, {@link + * Integer}, {@link Long}, {@link String}, {@link java.util.Optional}, {@link java.util.List}, + * {@link Object[]}. + */ +public record Variant(Signature signature, Object value) {} -- cgit v1.2.3