Carlos Florêncio
90 lines
2.2 KiB
Go
90 lines
2.2 KiB
Go
package process
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import "strings"
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// scanArgChars inspects each byte of s and returns whether any character
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// requires backslash-escaping (double-quote or backslash) and whether
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// the argument contains whitespace (space or tab).
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func scanArgChars(s string) (needsBackslash, hasSpace bool) {
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for i := 0; i < len(s); i++ {
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switch s[i] {
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case '"', '\\':
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needsBackslash = true
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case ' ', '\t':
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hasSpace = true
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}
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}
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return needsBackslash, hasSpace
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}
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// appendEscapedBytes appends the bytes of s to b applying MSDN
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// CommandLineToArgvW backslash-doubling rules for double-quote characters.
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// Returns the updated byte slice and the trailing slash count.
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func appendEscapedBytes(b []byte, s string) ([]byte, int) {
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slashes := 0
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for i := 0; i < len(s); i++ {
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c := s[i]
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switch c {
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default:
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slashes = 0
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case '\\':
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slashes++
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case '"':
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for ; slashes > 0; slashes-- {
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b = append(b, '\\')
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}
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b = append(b, '\\')
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}
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b = append(b, c)
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}
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return b, slashes
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}
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// escapeArg rewrites a command-line argument following the MSDN
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// CommandLineToArgvW parsing rules (same algorithm as Go's
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// syscall.EscapeArg on Windows):
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//
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// - every backslash (\) is doubled, but only if immediately
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// followed by a double quote (");
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// - every double quote (") is escaped with a backslash (\);
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// - finally, the argument is wrapped in double quotes only if
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// it contains spaces or tabs.
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// - an empty string becomes "" (two double-quote characters).
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func escapeArg(s string) string {
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if len(s) == 0 {
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return `""`
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}
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needsBackslash, hasSpace := scanArgChars(s)
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if !needsBackslash && !hasSpace {
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return s
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}
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if !needsBackslash {
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return `"` + s + `"`
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}
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var b []byte
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if hasSpace {
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b = append(b, '"')
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}
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b, slashes := appendEscapedBytes(b, s)
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if hasSpace {
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for ; slashes > 0; slashes-- {
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b = append(b, '\\')
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}
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b = append(b, '"')
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}
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return string(b)
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}
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// buildCmdLine joins arguments into a single command-line string
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// with proper quoting for Windows CreateProcess.
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func buildCmdLine(args []string) string {
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escaped := make([]string, len(args))
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for i, arg := range args {
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escaped[i] = escapeArg(arg)
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}
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return strings.Join(escaped, " ")
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}
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