feat: add header and comet info service (#15850)

Co-authored-by: Aaron Craelius <aaron@regen.network>

core/comet/doc.go

@@ -0,0 +1,7 @@
+/*
+Package comet defines the Comet Service interface and BlockInfo types which applications
+should use in order to get access to the current block's evidence, validators hash, proposer address.
+
+This information is specific to Comet
+*/
+package comet

core/comet/service.go

@@ -0,0 +1,68 @@
+package comet
+
+import (
+	"context"
+	"time"
+)
+
+// BlockInfoService is an interface that can be used to get information specific to Comet
+type BlockInfoService interface {
+	GetCometBlockInfo(context.Context) BlockInfo
+}
+
+// BlockInfo is the information comet provides apps in ABCI
+type BlockInfo interface {
+	GetEvidence() EvidenceList // Evidence misbehavior of the block
+	// ValidatorsHash returns the hash of the validators
+	// For Comet, it is the hash of the next validator set
+	GetValidatorsHash() []byte
+	GetProposerAddress() []byte // ProposerAddress returns the address of the block proposer
+	GetLastCommit() CommitInfo  // DecidedLastCommit returns the last commit info
+}
+
+// MisbehaviorType is the type of misbehavior for a validator
+type MisbehaviorType int32
+
+const (
+	Unknown           MisbehaviorType = 0
+	DuplicateVote     MisbehaviorType = 1
+	LightClientAttack MisbehaviorType = 2
+)
+
+// Validator is the validator information of ABCI
+type Validator interface {
+	Address() []byte
+	Power() int64
+}
+
+type EvidenceList interface {
+	Len() int
+	Get(int) Evidence
+}
+
+// Evidence is the misbehavior information of ABCI
+type Evidence interface {
+	Type() MisbehaviorType
+	Validator() Validator
+	Height() int64
+	Time() time.Time
+	TotalVotingPower() int64
+}
+
+// CommitInfo is the commit information of ABCI
+type CommitInfo interface {
+	Round() int32
+	Votes() VoteInfos
+}
+
+// VoteInfos is an interface to get specific votes in a efficient way
+type VoteInfos interface {
+	Len() int
+	Get(int) VoteInfo
+}
+
+// VoteInfo is the vote information of ABCI
+type VoteInfo interface {
+	Validator() Validator
+	SignedLastBlock() bool
+}

core/header/doc.go

@@ -0,0 +1,7 @@
+/*
+Package header defines a generalized Header type that all consensus & networking layers must provide.
+
+If modules need access to the current block header information, like height, hash, time, or chain ID
+they should use the Header Service interface.
+*/
+package header

core/header/service.go

@@ -0,0 +1,19 @@
+package header
+
+import (
+	"context"
+	"time"
+)
+
+// Service defines the interface in which you can get header information
+type Service interface {
+	GetHeaderInfo(context.Context) Info
+}
+
+// Info defines a struct that contains information about the header
+type Info struct {
+	Height  int64     // Height returns the height of the block
+	Hash    []byte    // Hash returns the hash of the block header
+	Time    time.Time // Time returns the time of the block
+	ChainID string    // ChainId returns the chain ID of the block
+}