office-gobmx/unoidl/README.md

Support for UNOIDL Registry Formats

Library_unoidl contains the unoidl::Manager and unoidl::Provider implementations for the following registry formats:

• The new UNOIDL binary types.rdb format.
• The old legacy binary types.rdb format (based on modules "store" and "registry").
• A source-file format, reading (multiple) UNOIDL entity definitions directly from a single .idl source file.
• A source-tree format, reading UNOIDL entity definitions directly from a tree of .idl source files rooted at a given directory. (Where an entity named foo.bar.Baz is expected in a file named foo/bar/Baz.idl within that tree.)

(While .idl files still contain #include directives for legacy idlc, the source- based formats ignore any preprocessing directives starting with # in the .idl files.) unoidl::Manager::addProvider transparently detects the registry format for a given URI and instantiates the corresponding provider implementation.

Executable_unoidl-write is a helper tool to convert from any of the registry formats to the UNOIDL format. It is used at build-time to compile UNOIDL format .rdb files (that are used at build-time only, or included in installation sets in URE or program/types/ or as part of bundled extensions that are created during the build and not merely included as pre-built .oxt files) from source .idl files. (The SDK still uses idlc and generates legacy format .rdb files for now.)

Executable_unoidl-read is a helper tool to convert from any of the registry formats to the source-file format. It can be used manually after a LibreOffice version update to create new reference registries for Executable_unoidl-check.

Executable_unoidl-check is a helper tool to check that one registry is backwards-compatible with another registry. It is used at build-time to detect inadvertent breakage of the udkapi and offapi APIs.

Specification of the New UNOIDL types.rdb Format

The format uses byte-oriented, platform-independent, binary files. Larger quantities are stored LSB first, without alignment requirements. Offsets are 32 bit, effectively limiting the overall file size to 4GB, but that is not considered a limitation in practice (and avoids unnecessary bloat compared to 64 bit offsets).

Annotations can be added for (non-module) entities and certain parts of such entities (e.g., both for an interface type definition and for a direct method of an interface type definition; the idea is that it can be added for direct parts that forma a "many-to-one" relationship; there is a tradeoff between generality of concept and size of representation, esp. for the C++ representation types in namespace unoidl) and consist of arbitrary sequences of name/value strings. Each name/value string is encoded as a single UTF-8 string containing a name (an arbitrary sequence of Unicode code points not containing U+003D EQUALS SIGN), optionally followed by U+003D EQUALS SIGN and a value (an arbitrary sequence of Unicode code points). The only annotation name currently in use is "deprecated" (without a value).

The following definitions are used throughout:

• UInt16: 2-byte value, LSB first
• UInt32: 4-byte value, LSB first
• UInt64: 8-byte value, LSB first
• Offset: UInt32 value, counting bytes from start of file
• NUL-Name: zero or more non-NUL US-ASCII bytes followed by a NUL byte
• Len-String: UInt32 number of characters, with 0x80000000 bit 0, followed by that many US-ASCII (for UNOIDL related names) resp. UTF-8 (for annotations) bytes
• Idx-String: either an Offset (with 0x80000000 bit 1) of a Len-String, or a Len-String
• Annotations: UInt32 number N of annotations followed by N * Idx-String
• Entry: Offset of NUL-Name followed by Offset of payload
• Map: zero or more Entries

The file starts with an 8 byte header, followed by information about the root map (unoidl-write generates files in a single depth-first pass, so the root map itself is at the end of the file):

• 7 byte magic header UNOIDL\xFF
• version byte 0
• Offset of root Map
• UInt32 number of entries of root Map ...

Files generated by unoidl-write follow that by a

"\0** Created by LibreOffice " LIBO_VERSION_DOTTED " unoidl-write **\0"

banner (cf. config_host/config_version.h.in), as a debugging aid. (Old versions used reg2unoidl instead of unoidl-write in that banner.)

Layout of per-entry payload in the root or a module Map:

• kind byte:

  • 0: module

    • followed by:
      • UInt32 number N1 of entries of Map
      • N1 * Entry

  • otherwise:

    • 0x80 bit: 1 if published

    • 0x40 bit: 1 if annotated

    • 0x20 bit: flag (may only be 1 for certain kinds, see below)

    • remaining bits:

      • 1: enum type

        • followed by:
          • UInt32 number N1 of members
          • N1 * tuple of:
            • Idx-String
            • UInt32
            • if annotated: Annotations

      • 2: plain struct type (with base if flag is 1)

        • followed by:
          • if "with base": Idx-String
          • UInt32 number N1 of direct members
          • N1 * tuple of:
            • Idx-String name
            • Idx-String type
            • if annotated: Annotations

      • 3: polymorphic struct type template

        • followed by:
          • UInt32 number N1 of type parameters
          • N1 * Idx-String
          • UInt32 number N2 of members
          • N2 * tuple of:
            • kind byte: 0x01 bit is 1 if parameterized type
            • Idx-String name
            • Idx-String type
            • if annotated: Annotations

      • 4: exception type (with base if flag is 1)

        • followed by:
          • if "with base": Idx-String
          • UInt32 number N1 of direct members
          • N1 * tuple of:
            • Idx-String name
            • Idx-String type
            • if annotated: Annotations

      • 5: interface type

        • followed by:
          • UInt32 number N1 of direct mandatory bases
          • N1 * tuple of:
            • Idx-String
            • if annotated: Annotations
          • UInt32 number N2 of direct optional bases
          • N2 * tuple of:
            • Idx-String
            • if annotated: Annotations
          • UInt32 number N3 of direct attributes
          • N3 * tuple of:
            • kind byte:
              • 0x02 bit: 1 if read-only
              • 0x01 bit: 1 if bound
            • Idx-String name
            • Idx-String type
            • UInt32 number N4 of get exceptions
            • N4 * Idx-String
            • UInt32 number N5 of set exceptions
            • N5 * Idx-String
            • if annotated: Annotations
          • UInt32 number N6 of direct methods
          • N6 * tuple of:
            • Idx-String name
            • Idx-String return type
            • UInt32 number N7 of parameters
            • N7 * tuple of:
              • direction byte: 0 for in, 1 for out, 2 for in-out
              • Idx-String name
              • Idx-String type
            • UInt32 number N8 of exceptions
            • N8 * Idx-String
            • if annotated: Annotations

      • 6: typedef

        • followed by:
          • Idx-String

      • 7: constant group

        • followed by:
          • UInt32 number N1 of entries of Map
          • N1 * Entry

      • 8: single-interface--based service (with default constructor if flag is 1)

        • followed by:
          • Idx-String
          • if not "with default constructor":
            • UInt32 number N1 of constructors
            • N1 * tuple of:
              • Idx-String
              • UInt32 number N2 of parameters
              • N2 * tuple of
                • kind byte: 0x04 bit is 1 if rest parameter
                • Idx-String name
                • Idx-String type
              • UInt32 number N3 of exceptions
              • N3 * Idx-String
              • if annotated: Annotations

      • 9: accumulation-based service

        • followed by:
          • UInt32 number N1 of direct mandatory base services
          • N1 * tuple of:
            • Idx-String
            • if annotated: Annotations
          • UInt32 number N2 of direct optional base services
          • N2 * tuple of:
            • Idx-String
            • if annotated: Annotations
          • UInt32 number N3 of direct mandatory base interfaces
          • N3 * tuple of:
            • Idx-String
            • if annotated: Annotations
          • UInt32 number N4 of direct optional base interfaces
          • N4 * tuple of:
            • Idx-String
            • if annotated: Annotations
          • UInt32 number N5 of direct properties
          • N5 * tuple of:
            • UInt16 kind:
              • 0x0100 bit: 1 if optional
              • 0x0080 bit: 1 if removable
              • 0x0040 bit: 1 if maybedefault
              • 0x0020 bit: 1 if maybeambiguous
              • 0x0010 bit: 1 if readonly
              • 0x0008 bit: 1 if transient
              • 0x0004 bit: 1 if constrained
              • 0x0002 bit: 1 if bound
              • 0x0001 bit: 1 if maybevoid
              • Idx-String name
              • Idx-String type
              • if annotated: Annotations

      • 10: interface-based singleton

        • followed by:
        • Idx-String

      • 11: service-based singleton

        • followed by:
          • Idx-String

    • if annotated, followed by: Annotations

Layout of per-entry payload in a constant group Map:

• kind byte:

  • 0x80 bit: 1 if annotated

  • remaining bits:

    • 0: BOOLEAN

      • followed by value byte, 0 represents false, 1 represents true

    • 1: BYTE

      • followed by value byte, representing values with two's complement

    • 2: SHORT

      • followed by UInt16 value, representing values with two's complement

    • 3: UNSIGNED SHORT

      • followed by UInt16 value

    • 4: LONG

      • followed by UInt32 value, representing values with two's complement

    • 5: UNSIGNED LONG

      • followed by UInt32 value

    • 6: HYPER

      • followed by UInt64 value, representing values with two's complement

    • 7: UNSIGNED HYPER

      • followed by UInt64 value

    • 8: FLOAT

      • followed by 4-byte value, representing values in ISO 60599 binary32 format, LSB first

    • 9: DOUBLE

      • followed by 8-byte value, representing values in ISO 60599 binary64 format, LSB first

• if annotated, followed by: Annotations