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