From 9034590e873a1a0532b217467e167645745f16d4 Mon Sep 17 00:00:00 2001
From: Howard Yeh <howard@metacircus.com>
Date: Mon, 11 Dec 2017 17:15:31 +0800
Subject: [PATCH] variable expansion package

---
 cli.go           | 16 ++++++++++++++++
 deploy.go        |  9 ++++++++-
 encode.go        |  4 +++-
 varstr/expand.go | 48 ++++++++++++++++++++++++++++++++++++++++++++++++
 4 files changed, 75 insertions(+), 2 deletions(-)
 create mode 100644 varstr/expand.go

diff --git a/cli.go b/cli.go
index f294660..5163e2a 100644
--- a/cli.go
+++ b/cli.go
@@ -1,6 +1,7 @@
 package solar
 
 import (
+	"encoding/hex"
 	"fmt"
 	"log"
 	"net/url"
@@ -13,6 +14,7 @@ import (
 	"github.com/qtumproject/solar/deployer"
 	"github.com/qtumproject/solar/deployer/eth"
 	"github.com/qtumproject/solar/deployer/qtum"
+	"github.com/qtumproject/solar/varstr"
 	kingpin "gopkg.in/alecthomas/kingpin.v2"
 )
 
@@ -106,6 +108,20 @@ func (c *solarCLI) QtumRPC() *qtum.RPC {
 	return rpc
 }
 
+// ExpandJSONParams uses variable substitution syntax (e.g. $Foo, ${Foo}) to as placeholder for contract addresses
+func (c *solarCLI) ExpandJSONParams(jsonParams string) string {
+	repo := c.ContractsRepository()
+
+	return varstr.Expand(jsonParams, func(key string) string {
+		contract, found := repo.Get(key)
+		if !found {
+			panic(errors.Errorf("Invalid address expansion: %s", key))
+		}
+
+		return fmt.Sprintf("%#v", hex.EncodeToString(contract.Address))
+	})
+}
+
 func (c *solarCLI) Deployer() (deployer deployer.Deployer) {
 	log := log.New(os.Stderr, "", log.Lshortfile)
 
diff --git a/deploy.go b/deploy.go
index e3dfe1b..864a691 100644
--- a/deploy.go
+++ b/deploy.go
@@ -68,7 +68,14 @@ func init() {
 
 		fmt.Printf("   \033[36mdeploy\033[0m %s => %s\n", target.file, target.name)
 
-		err = deployer.CreateContract(contract, []byte(*jsonParams), target.name, *force, *aslib)
+		var params []byte
+		if jsonParams != nil {
+			jsonParams := solar.ExpandJSONParams(*jsonParams)
+
+			params = []byte(jsonParams)
+		}
+
+		err = deployer.CreateContract(contract, params, target.name, *force, *aslib)
 		if err != nil {
 			fmt.Println("\u2757\ufe0f \033[36mdeploy\033[0m", err)
 			return
diff --git a/encode.go b/encode.go
index 655b806..e336764 100644
--- a/encode.go
+++ b/encode.go
@@ -30,7 +30,9 @@ func init() {
 
 		var params []interface{}
 		if jsonParams != nil {
-			err := json.Unmarshal([]byte(*jsonParams), &params)
+			jsonParams := solar.ExpandJSONParams(*jsonParams)
+
+			err := json.Unmarshal([]byte(jsonParams), &params)
 			if err != nil {
 				return err
 			}
diff --git a/varstr/expand.go b/varstr/expand.go
new file mode 100644
index 0000000..22c3f29
--- /dev/null
+++ b/varstr/expand.go
@@ -0,0 +1,48 @@
+package varstr
+
+// Modified from stdlib's os.Expand function. Remove special shell variable expansion.
+// https://github.com/golang/go/blob/0da486dc72743faa6e601444dcc35728704a1545/src/os/env.go#L13
+
+// Expand replaces ${var} or $var in the string based on the mapping function.
+func Expand(s string, mapping func(string) string) string {
+	buf := make([]byte, 0, 2*len(s))
+	// ${} is all ASCII, so bytes are fine for this operation.
+	i := 0
+	for j := 0; j < len(s); j++ {
+		if s[j] == '$' && j+1 < len(s) {
+			buf = append(buf, s[i:j]...)
+			name, w := getVarName(s[j+1:])
+			buf = append(buf, mapping(name)...)
+			j += w
+			i = j + 1
+		}
+	}
+	return string(buf) + s[i:]
+}
+
+// isAlphaNum reports whether the byte is an ASCII letter, number, or underscore
+func isAlphaNum(c uint8) bool {
+	return c == '_' || '0' <= c && c <= '9' || 'a' <= c && c <= 'z' || 'A' <= c && c <= 'Z'
+}
+
+// getVarName returns the name that begins the string and the number of bytes
+// consumed to extract it. If the name is enclosed in {}, it's part of a ${}
+// expansion and two more bytes are needed than the length of the name.
+func getVarName(s string) (string, int) {
+	if s[0] == '{' {
+		// Scan to closing brace
+		for i := 1; i < len(s); i++ {
+			if s[i] == '}' {
+				return s[1:i], i + 1
+			}
+		}
+		return "", 1 // Bad syntax; just eat the brace.
+
+	}
+
+	// Scan alphanumerics.
+	var i int
+	for i = 0; i < len(s) && isAlphaNum(s[i]); i++ {
+	}
+	return s[:i], i
+}