Add GOCACHEPROG binary and pre-build stdlib cache for Go 1.25.5

- Build a new cacheprog binary to enable read-only cache access.
- Pre-build the standard library cache in a dedicated GOCACHE directory.
- Update compile script to use GOCACHEPROG for improved caching during builds.

Author: koki-develop

packages/.gitignore

@@ -5,4 +5,5 @@
 !*/*/environment
 !*/*/run
 !*/*/compile
-!*/*/test.*
+!*/*/test.*
+!*/*/cacheprog.go

packages/go/1.25.5/build.sh

@@ -2,3 +2,11 @@
 curl -LO https://go.dev/dl/go1.25.5.linux-amd64.tar.gz
 tar -xzf go1.25.5.linux-amd64.tar.gz
 rm go1.25.5.linux-amd64.tar.gz
+
+# Build GOCACHEPROG binary for read-only cache access
+CGO_ENABLED=0 ./go/bin/go build -o cacheprog cacheprog.go
+
+# Pre-build standard library cache
+export GOCACHE=$PWD/cache
+mkdir -p $GOCACHE
+CGO_ENABLED=0 ./go/bin/go build std

packages/go/1.25.5/cacheprog.go

@@ -0,0 +1,104 @@
+package main
+
+import (
+	"bufio"
+	"encoding/hex"
+	"encoding/json"
+	"os"
+	"path/filepath"
+	"strconv"
+	"strings"
+)
+
+type Request struct {
+	ID       int64  `json:"ID"`
+	Command  string `json:"Command"`
+	ActionID []byte `json:"ActionID,omitempty"`
+}
+
+type Response struct {
+	ID            int64    `json:"ID"`
+	KnownCommands []string `json:"KnownCommands,omitempty"`
+	Miss          bool     `json:"Miss,omitempty"`
+	OutputID      []byte   `json:"OutputID,omitempty"`
+	Size          int64    `json:"Size,omitempty"`
+	DiskPath      string   `json:"DiskPath,omitempty"`
+}
+
+func main() {
+	if len(os.Args) < 2 {
+		os.Exit(1)
+	}
+	cacheDir := os.Args[1]
+
+	enc := json.NewEncoder(os.Stdout)
+	enc.Encode(Response{ID: 0, KnownCommands: []string{"get", "close"}})
+
+	scanner := bufio.NewScanner(os.Stdin)
+	for scanner.Scan() {
+		var req Request
+		if err := json.Unmarshal(scanner.Bytes(), &req); err != nil {
+			continue
+		}
+
+		switch req.Command {
+		case "get":
+			enc.Encode(handleGet(cacheDir, req))
+		case "close":
+			enc.Encode(Response{ID: req.ID})
+			return
+		}
+	}
+}
+
+func handleGet(cacheDir string, req Request) Response {
+	actionHex := hex.EncodeToString(req.ActionID)
+	if len(actionHex) < 2 {
+		return Response{ID: req.ID, Miss: true}
+	}
+
+	actionPath := filepath.Join(cacheDir, actionHex[:2], actionHex+"-a")
+	data, err := os.ReadFile(actionPath)
+	if err != nil {
+		return Response{ID: req.ID, Miss: true}
+	}
+
+	outputID, size, err := parseActionEntry(data)
+	if err != nil {
+		return Response{ID: req.ID, Miss: true}
+	}
+
+	outputHex := hex.EncodeToString(outputID)
+	dataPath := filepath.Join(cacheDir, outputHex[:2], outputHex+"-d")
+	if _, err := os.Stat(dataPath); err != nil {
+		return Response{ID: req.ID, Miss: true}
+	}
+
+	return Response{
+		ID:       req.ID,
+		OutputID: outputID,
+		Size:     size,
+		DiskPath: dataPath,
+	}
+}
+
+// parseActionEntry parses: "v1 <actionHex> <outputHex> <size> <time>\n"
+func parseActionEntry(data []byte) ([]byte, int64, error) {
+	line := strings.TrimSpace(string(data))
+	fields := strings.Fields(line)
+	if len(fields) < 4 || fields[0] != "v1" {
+		return nil, 0, os.ErrInvalid
+	}
+
+	outputID, err := hex.DecodeString(fields[2])
+	if err != nil {
+		return nil, 0, err
+	}
+
+	size, err := strconv.ParseInt(fields[3], 10, 64)
+	if err != nil {
+		return nil, 0, err
+	}
+
+	return outputID, size, nil
+}

packages/go/1.25.5/compile

@@ -1,5 +1,6 @@
 #!/usr/bin/env bash
 
 mv $1 $1.go
-GOCACHE=$PWD go build -o binary *.go
+export GOCACHEPROG="/piston/packages/go/1.25.5/cacheprog /piston/packages/go/1.25.5/cache"
+CGO_ENABLED=0 go build -o binary *.go
 chmod +x binary