• As resources are tightly bound to the application's jar files, the resources must be re-delivered to users every time code in the same jar file is updated, even if none of the resources changed. If a jar file contains a gigabyte of resource files, and a single line of code in a class in the jar file is changed, then users must be sent a new copy of the gigabyte-sized jar file when the application is updated.
• As the Java runtime environment allows for classes to be loaded over a network connection, resources and classes alike are limited to being accessed in a stream-like fashion, unless the application introspectively tries various hacks to locate its own jar files (which may or may not be present in the filesystem). This precludes accessing large resource files such as audio files in a random-access fashion. It also precludes memory mapping resources for efficient uploading to GPUs and other external hardware.
• Prior to the introduction of the module system in the Java runtime, any class could access the resources of any other class, intentionally or unintentionally. This can introduce accidental implicit dependencies across codebases, which can be broken unexpectedly when a (transitive) dependency happens to be removed from the set of packages that comprise an application.

• Resources in sunburst are simple files in the filesystem. They can be accessed in a random-access fashion, memory-mapped, or subjected to any of the other operations supported by the host filesystem.
• Resources in sunburst are located using a simple URI-like mechanism that insulates the application from having to know where to find resources in the filesystem. This preserves most of the convenience of the Class.getResource() API.
• Resources in sunburst are integrity-checked. Resources are inserted into a content-addressed directory structure indexed by cryptographic hashes. Individual corrupted or missing resources can be automatically re-downloaded without requiring the re-download of all resources. This saves greatly on network bandwidth during updates.
• Resources in sunburst are deduplicated. Resources are indexed by their cryptographic hash, so if many different packages reference a resource, the resource is only stored in the filesystem once. For large files, this can entail significant space savings.
• Resources in sunburst are grouped into strongly-versioned packages, with non-snapshot versions of packages being treated as immutable. Packages must be explicitly imported by Java code in order to be visible to it; accidental implicit dependencies are prevented. APIs are provided to check that all of the application's required sunburst packages are present and installed on application startup.
• Packages in sunburst are backed by transactional storage, meaning that packages can be safely and atomically installed/uninstalled/updated, even from multiple processes concurrently. Multiple versions of the same package can be installed concurrently, and an unlimited number of applications can share the same sunburst database if desired.

<?xml version="1.0" encoding="UTF-8" ?>

<!--
  Copyright © 2022 Mark Raynsford <code@io7m.com> https://www.io7m.com

  Permission to use, copy, modify, and/or distribute this software for any
  purpose with or without fee is hereby granted, provided that the above
  copyright notice and this permission notice appear in all copies.

  THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
  WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
  MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
  SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
  WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
  ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR
  IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
-->

<schema xmlns="http://www.w3.org/2001/XMLSchema"
        targetNamespace="urn:com.io7m.sunburst:peer:1"
        xmlns:p="urn:com.io7m.sunburst:peer:1">

  <simpleType name="PackageVersionQualifierT">
    <annotation>
      <documentation>
        The type of package version qualifiers. See com.io7m.sunburst.model.SBPackageVersion.
      </documentation>
    </annotation>
    <restriction base="string">
      <pattern value="[A-Za-z0-9\-]+(\.[A-Za-z0-9\-]+)*"/>
      <maxLength value="255"/>
    </restriction>
  </simpleType>

  <simpleType name="PackageNameT">
    <annotation>
      <documentation>
        The type of package names. See com.io7m.sunburst.model.SBPackageIdentifier.
      </documentation>
    </annotation>
    <restriction base="string">
      <pattern value="[a-z][a-z0-9_-]*(\.[a-z][a-z0-9_-]*)*"/>
      <maxLength value="255"/>
    </restriction>
  </simpleType>

  <element name="Import">
    <annotation>
      <documentation>
        A unique package import.
      </documentation>
    </annotation>
    <complexType>
      <attribute name="Name"
                 type="p:PackageNameT"
                 use="required"/>
      <attribute name="Major"
                 type="unsignedInt"
                 use="required"/>
      <attribute name="Minor"
                 type="unsignedInt"
                 use="required"/>
      <attribute name="Patch"
                 type="unsignedInt"
                 use="required"/>
      <attribute name="Qualifier"
                 type="p:PackageVersionQualifierT"
                 use="optional"/>
    </complexType>
  </element>

  <element name="Peer">
    <annotation>
      <documentation>
        A peer declaration.
      </documentation>
    </annotation>
    <complexType>
      <sequence minOccurs="0" maxOccurs="unbounded">
        <element ref="p:Import"/>
      </sequence>
      <attribute name="Name"
                 type="p:PackageNameT"
                 use="required"/>
    </complexType>
    <key name="ImportPackageKey">
      <selector xpath="p:Import"/>
      <field xpath="@Name"/>
    </key>
  </element>

  <element name="Peers">
    <annotation>
      <documentation>
        The top-level peers declaration.
      </documentation>
    </annotation>
    <complexType>
      <sequence minOccurs="0" maxOccurs="unbounded">
        <element ref="p:Peer"/>
      </sequence>
    </complexType>
    <key name="PeerNameKey">
      <selector xpath="p:Peer"/>
      <field xpath="@Name"/>
    </key>
  </element>

</schema>

<?xml version="1.0" encoding="UTF-8" ?>

<!--
  Copyright © 2022 Mark Raynsford <code@io7m.com> https://www.io7m.com

  Permission to use, copy, modify, and/or distribute this software for any
  purpose with or without fee is hereby granted, provided that the above
  copyright notice and this permission notice appear in all copies.

  THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
  WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
  MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
  SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
  WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
  ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR
  IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
-->

<schema xmlns="http://www.w3.org/2001/XMLSchema"
        targetNamespace="urn:com.io7m.sunburst:package:1"
        xmlns:p="urn:com.io7m.sunburst:package:1">

  <simpleType name="NameT">
    <annotation>
      <documentation>
        The type of package names. See com.io7m.sunburst.model.SBPackageIdentifier.
      </documentation>
    </annotation>
    <restriction base="string">
      <pattern value="([a-z][a-z0-9_-]{0,63})(\.[a-z][a-z0-9_-]{0,62}){0,15}"/>
      <maxLength value="1024"/>
    </restriction>
  </simpleType>

  <simpleType name="QualifierT">
    <annotation>
      <documentation>
        The type of package version qualifiers. See com.io7m.verona.core.VersionQualifier.
      </documentation>
    </annotation>
    <restriction base="string">
      <pattern value="[A-Za-z0-9\-]+(\.[A-Za-z0-9\-]+)*"/>
      <maxLength value="255"/>
    </restriction>
  </simpleType>

  <simpleType name="HashAlgorithmT">
    <annotation>
      <documentation>
        An index for a hash algorithm.
      </documentation>
    </annotation>
    <restriction base="string">
      <enumeration value="SHA2_256">
        <annotation>
          <documentation>
            256-bit SHA-2.
          </documentation>
        </annotation>
      </enumeration>
    </restriction>
  </simpleType>

  <simpleType name="PathT">
    <annotation>
      <documentation>
        A normalized path. Paths can be used to refer to objects inside packages without having to refer to them by
        their hash value.
      </documentation>
    </annotation>
    <restriction base="string">
      <pattern value="/([a-z0-9_\\.-]+)(/[a-z0-9_\\.-]+)*"/>
      <maxLength value="255"/>
    </restriction>
  </simpleType>

  <simpleType name="HashT">
    <annotation>
      <documentation>
        The base 16 representation of a hash value.
      </documentation>
    </annotation>
    <restriction base="string">
      <pattern value="[A-F0-9]+"/>
      <maxLength value="255"/>
    </restriction>
  </simpleType>

  <simpleType name="ContentTypeT">
    <annotation>
      <documentation>
        An IANA media type. Purely informative, and not checked for validity.
      </documentation>
    </annotation>
    <restriction base="string">
      <maxLength value="255"/>
    </restriction>
  </simpleType>

  <element name="Version">
    <annotation>
      <documentation>
        A (semantic) package version. The major, minor, and patch version numbers correspond to the version number
        components defined in the Semantic Versioning 2.0 specification. The optional qualifier can be used to indicate
        alpha/beta/snapshot versions.
      </documentation>
    </annotation>
    <complexType>
      <attribute name="Major"
                 type="unsignedInt"
                 use="required"/>
      <attribute name="Minor"
                 type="unsignedInt"
                 use="required"/>
      <attribute name="Patch"
                 type="unsignedInt"
                 use="required"/>
      <attribute name="Qualifier"
                 type="p:QualifierT"
                 use="optional"/>
    </complexType>
  </element>

  <element name="Identifier">
    <annotation>
      <documentation>
        A unique package identifier.
      </documentation>
    </annotation>
    <complexType>
      <sequence>
        <element ref="p:Version"/>
      </sequence>
      <attribute name="Name"
                 type="p:NameT"
                 use="required"/>
    </complexType>
  </element>

  <element name="Meta">
    <annotation>
      <documentation>
        A metadata value.
      </documentation>
    </annotation>
    <complexType>
      <attribute name="Key"
                 type="string"
                 use="required"/>
      <attribute name="Value"
                 type="string"
                 use="required"/>
    </complexType>
  </element>

  <element name="Metadata">
    <annotation>
      <documentation>
        The set of optional metadata values.
      </documentation>
    </annotation>
    <complexType>
      <sequence minOccurs="1"
                maxOccurs="unbounded">
        <element ref="p:Meta"/>
      </sequence>
    </complexType>
    <key name="MetaKey">
      <selector xpath="p:Meta"/>
      <field xpath="@Key"/>
    </key>
  </element>

  <element name="Entry">
    <annotation>
      <documentation>
        An entry within a package. This is an opaque blob of data that can be uniquely identified by its hash, and
        assigned a path that can be used to refer to it.
      </documentation>
    </annotation>
    <complexType>
      <attribute name="Path"
                 type="p:PathT"
                 use="required"/>
      <attribute name="HashAlgorithm"
                 type="p:HashAlgorithmT"
                 use="required"/>
      <attribute name="HashValue"
                 type="p:HashT"
                 use="required"/>
      <attribute name="Size"
                 type="unsignedLong"
                 use="required"/>
      <attribute name="ContentType"
                 type="p:ContentTypeT"
                 use="required"/>
    </complexType>
  </element>

  <element name="Entries">
    <annotation>
      <documentation>
        The entries within a package.
      </documentation>
    </annotation>
    <complexType>
      <sequence>
        <element ref="p:Entry"
                 minOccurs="1"
                 maxOccurs="unbounded"/>
      </sequence>
    </complexType>
    <key name="EntryKey">
      <selector xpath="p:Entry"/>
      <field xpath="@Path"/>
    </key>
  </element>

  <element name="Package">
    <annotation>
      <documentation>
        The top-level package declaration.
      </documentation>
    </annotation>
    <complexType>
      <sequence>
        <element ref="p:Identifier"/>
        <element ref="p:Metadata"
                 minOccurs="0"
                 maxOccurs="1"/>
        <element ref="p:Entries"
                 minOccurs="0"
                 maxOccurs="1"/>
      </sequence>
    </complexType>
  </element>

</schema>

Copyright © 2021 Mark Raynsford <code@io7m.com> https://www.io7m.com

This book is placed into the public domain for free use by anyone
for any purpose. It may be freely used, modified, and distributed.

In jurisdictions that do not recognise the public domain this book
may be freely used, modified, and distributed without restriction.

This book comes with absolutely no warranty.