Involved Source Files
Package filetype provides functionality for wrapping descriptors
with Go type information.
Package-Level Type Names (total 5, in which 2 are exported)
/* sort exporteds by: | */
Builder constructs type descriptors from a raw file descriptor
and associated Go types for each enum and message declaration.
Flattened Ordering
The protobuf type system represents declarations as a tree. Certain nodes in
the tree require us to either associate it with a concrete Go type or to
resolve a dependency, which is information that must be provided separately
since it cannot be derived from the file descriptor alone.
However, representing a tree as Go literals is difficult to simply do in a
space and time efficient way. Thus, we store them as a flattened list of
objects where the serialization order from the tree-based form is important.
The "flattened ordering" is defined as a tree traversal of all enum, message,
extension, and service declarations using the following algorithm:
def VisitFileDecls(fd):
for e in fd.Enums: yield e
for m in fd.Messages: yield m
for x in fd.Extensions: yield x
for s in fd.Services: yield s
for m in fd.Messages: yield from VisitMessageDecls(m)
def VisitMessageDecls(md):
for e in md.Enums: yield e
for m in md.Messages: yield m
for x in md.Extensions: yield x
for m in md.Messages: yield from VisitMessageDecls(m)
The traversal starts at the root file descriptor and yields each direct
declaration within each node before traversing into sub-declarations
that children themselves may have.
DependencyIndexes is an ordered list of indexes into GoTypes for the
dependencies of messages, extensions, or services.
There are 5 sub-lists in "flattened ordering" concatenated back-to-back:
0. Message field dependencies: list of the enum or message type
referred to by every message field.
1. Extension field targets: list of the extended parent message of
every extension.
2. Extension field dependencies: list of the enum or message type
referred to by every extension field.
3. Service method inputs: list of the input message type
referred to by every service method.
4. Service method outputs: list of the output message type
referred to by every service method.
The offset into DependencyIndexes for the start of each sub-list
is appended to the end in reverse order.
EnumInfos is a list of enum infos in "flattened ordering".
ExtensionInfos is a list of extension infos in "flattened ordering".
Each element is initialized and registered with the protoregistry package.
Requirement: len(LegacyExtensions) == len(Build.Extensions)
File is the underlying file descriptor builder.
GoTypes is a unique set of the Go types for all declarations and
dependencies. Each type is represented as a zero value of the Go type.
Declarations are Go types generated for enums and messages directly
declared (not publicly imported) in the proto source file.
Messages for map entries are accounted for, but represented by nil.
Enum declarations in "flattened ordering" come first, followed by
message declarations in "flattened ordering".
Dependencies are Go types for enums or messages referenced by
message fields (excluding weak fields), for parent extended messages of
extension fields, for enums or messages referenced by extension fields,
and for input and output messages referenced by service methods.
Dependencies must come after declarations, but the ordering of
dependencies themselves is unspecified.
MessageInfos is a list of message infos in "flattened ordering".
If provided, the GoType and PBType for each element is populated.
Requirement: len(MessageInfos) == len(Build.Messages)
TypeRegistry is the registry to register each type descriptor.
If nil, it uses protoregistry.GlobalTypes.
( T) Build() (out Out)
The pages are generated with Goldsv0.3.2. (GOOS=linux GOARCH=amd64)
Golds is a Go 101 project developed by Tapir Liu.
PR and bug reports are welcome and can be submitted to the issue list.
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