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ChangeLog the fixes from pr #25. Fixes #125, #126
2017-10-03, Gary Kramlich
674d936a6785
ChangeLog the fixes from pr #25. Fixes #125, #126
/*
* Convey
* Copyright 2016-2017 Gary Kramlich <grim@reaperworld.com>
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
package
environment
import
(
"fmt"
"os"
"strings"
)
type
envMapper
struct
{
env
[]
string
}
func
(
e
*
envMapper
)
Map
(
name
string
)
string
{
for
_
,
item
:=
range
e
.
env
{
if
parts
:=
strings
.
SplitN
(
item
,
"="
,
2
);
parts
[
0
]
==
name
{
if
len
(
parts
)
==
2
{
return
parts
[
1
]
}
return
os
.
Getenv
(
name
)
}
}
return
"$"
+
name
}
// Mapper will replace ${TEMPLATE} patterns in the string with the KEY=VAL pairs
// in the given environment. This function will replace patterns recursively, so
// if VAL has the form ${TEMPLATE}, it will be replaced again.
func
Mapper
(
str
string
,
env
[]
string
)
(
string
,
error
)
{
mapper
:=
envMapper
{
env
}
last
:=
str
next
:=
os
.
Expand
(
last
,
mapper
.
Map
)
prev
:=
map
[
string
]
struct
{}{}
for
last
!=
next
{
if
_
,
ok
:=
prev
[
next
];
ok
{
return
""
,
fmt
.
Errorf
(
"infinite environment mapping loop while expanding '%s'"
,
next
)
}
last
=
next
next
=
os
.
Expand
(
last
,
mapper
.
Map
)
prev
[
last
]
=
struct
{}{}
}
return
next
,
nil
}
// SliceMapper calls Mapper for each item in a slice and returns a new slice.
func
SliceMapper
(
slice
[]
string
,
env
[]
string
)
([]
string
,
error
)
{
mapped
:=
[]
string
{}
for
_
,
template
:=
range
slice
{
expanded
,
err
:=
Mapper
(
template
,
env
)
if
err
!=
nil
{
return
nil
,
err
}
mapped
=
append
(
mapped
,
expanded
)
}
return
mapped
,
nil
}