gno.land/r/moul/x/daily/ringlog/v0⧉

1// Package ringlog is an on-chain port of Go's container/ring: a fixed-capacity2// circular message board where new posts overwrite the oldest entries once full.3package ringlog45import (6	"chain/runtime"7	"chain/runtime/unsafe"8	"strconv"9	"strings"10)1112// Cap is the maximum number of messages the ring buffer holds.13const Cap = 161415// Entry is a single posted message.16type Entry struct {17	Author  address18	Message string19	Height  int6420}2122var (23	buf   [Cap]Entry // the ring storage24	head  int        // index of the next write slot25	count int        // number of entries currently stored (0 ≤ count ≤ Cap)26)2728// Post adds a message to the ring buffer.29// Once Cap entries are stored, the oldest entry is overwritten.30func Post(msg string) {31	msg = strings.TrimSpace(msg)32	if len(msg) == 0 {33		panic("message cannot be empty")34	}35	if len(msg) > 280 {36		panic("message too long (max 280 chars)")37	}38	buf[head] = Entry{39		Author:  unsafe.PreviousRealm().Address(),40		Message: msg,41		Height:  runtime.ChainHeight(),42	}43	head = (head + 1) % Cap44	if count < Cap {45		count++46	}47}4849// Entries returns all stored messages in chronological order (oldest first).50func Entries() []Entry {51	if count == 0 {52		return nil53	}54	result := make([]Entry, count)55	oldest := (head - count + Cap) % Cap56	for i := 0; i < count; i++ {57		result[i] = buf[(oldest+i)%Cap]58	}59	return result60}6162// Len returns the number of messages currently stored.63func Len() int { return count }6465// Render displays the ring buffer as a Markdown page.66func Render(path string) string {67	var sb strings.Builder6869	sb.WriteString("# RingLog\n\n")70	sb.WriteString("> A ring-buffer message board (capacity: **")71	sb.WriteString(strconv.Itoa(Cap))72	sb.WriteString("**). New messages overwrite the oldest once the buffer is full.\n\n")7374	if count == 0 {75		sb.WriteString("*No messages yet. Call `Post(msg)` to add one.*\n")76		return sb.String()77	}7879	sb.WriteString("| # | Author | Block | Message |\n")80	sb.WriteString("|---|--------|-------|---------|\n")8182	entries := Entries()83	for i, e := range entries {84		sb.WriteString("| ")85		sb.WriteString(strconv.Itoa(i + 1))86		sb.WriteString(" | `")87		sb.WriteString(shorten(e.Author.String()))88		sb.WriteString("` | ")89		sb.WriteString(strconv.FormatInt(e.Height, 10))90		sb.WriteString(" | ")91		sb.WriteString(e.Message)92		sb.WriteString(" |\n")93	}9495	sb.WriteString("\n*Showing ")96	sb.WriteString(strconv.Itoa(count))97	sb.WriteString(" of ")98	sb.WriteString(strconv.Itoa(Cap))99	sb.WriteString(" slots used.*\n")100101	return sb.String()102}103104// shorten trims a long address for display.105func shorten(s string) string {106	if len(s) <= 14 {107		return s108	}109	return s[:6] + "…" + s[len(s)-6:]110}111