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[#186] netmap: Marshal policy with brackets

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Brackets can be semantically important and must not be omitted,
otherwise the output is plain wrong.
We do not take the responsibility to preserve every bracket, though,
because parser does some optimizations related to grouping long chains
of filters combined with the same operation.

Signed-off-by: Evgenii Stratonikov <e.stratonikov@yadro.com>
This commit is contained in:
Evgenii Stratonikov 2023-10-26 13:15:40 +03:00
parent 20d325e307
commit a02c0bfac8
2 changed files with 91 additions and 4 deletions
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21
netmap/policy.go
View file

@ -455,7 +455,7 @@ func (p PlacementPolicy) WriteStringTo(w io.StringWriter) (err error) {
return err
}
err = writeFilterStringTo(w, p.filters[i])
err = writeFilterStringTo(w, p.filters[i], false)
if err != nil {
return err
}
@ -464,7 +464,7 @@ func (p PlacementPolicy) WriteStringTo(w io.StringWriter) (err error) {
return nil
}
func writeFilterStringTo(w io.StringWriter, f netmap.Filter) error {
func writeFilterStringTo(w io.StringWriter, f netmap.Filter, mayNeedOuterBrackets bool) error {
var err error
var s string
op := f.GetOp()
@ -489,7 +489,7 @@ func writeFilterStringTo(w io.StringWriter, f netmap.Filter) error {
if err != nil {
return err
}
err = writeFilterStringTo(w, inner[0])
err = writeFilterStringTo(w, inner[0], false)
if err != nil {
return err
}
@ -498,6 +498,13 @@ func writeFilterStringTo(w io.StringWriter, f netmap.Filter) error {
return err
}
} else {
useBrackets := mayNeedOuterBrackets && op == netmap.OR && len(inner) > 1
if useBrackets {
_, err = w.WriteString("(")
if err != nil {
return err
}
}
for i := range inner {
if i != 0 {
_, err = w.WriteString(" " + op.String() + " ")
@ -505,7 +512,13 @@ func writeFilterStringTo(w io.StringWriter, f netmap.Filter) error {
return err
}
}
err = writeFilterStringTo(w, inner[i])
err = writeFilterStringTo(w, inner[i], true)
if err != nil {
return err
}
}
if useBrackets {
_, err = w.WriteString(")")
if err != nil {
return err
}

74
netmap/policy_test.go
View file

@ -1,6 +1,7 @@
package netmap_test
import (
"strings"
"testing"
. "git.frostfs.info/TrueCloudLab/frostfs-sdk-go/netmap"
@ -29,6 +30,79 @@ func TestPlacementPolicyEncoding(t *testing.T) {
})
}
func TestPlacementPolicyWriteString(t *testing.T) {
var testCases = []struct {
name string
input string
output string // If the output is empty, make it equal to input.
}{
{
name: "no compound operators",
input: `REP 1
CBF 1
SELECT 1 FROM Color
FILTER Color EQ Red AS Color`,
},
{
name: "no brackets in single level same-operator chain",
input: `REP 1
CBF 1
SELECT 1 FROM Color
FILTER Color EQ Red OR Color EQ Blue OR Color EQ Green AS Color`,
},
{
name: "no brackets aroung higher precedence op",
input: `REP 1
CBF 1
SELECT 1 FROM Color
FILTER Color EQ Red OR Color EQ Blue AND Color NE Green AS Color`,
},
{
name: "no brackets aroung higher precedence op, even if present in the input",
input: `REP 1
CBF 1
SELECT 1 FROM Color
FILTER Color EQ Red OR (Color EQ Blue AND Color NE Green) AS Color`,
output: `REP 1
CBF 1
SELECT 1 FROM Color
FILTER Color EQ Red OR Color EQ Blue AND Color NE Green AS Color`,
},
{
name: "brackets aroung lower precedence op",
input: `REP 1
CBF 1
SELECT 1 FROM Color
FILTER (Color EQ Red OR Color EQ Blue) AND Color NE Green AS Color`,
},
{
name: "no extra brackets for bracketed same-operator chain",
input: `REP 1
CBF 1
SELECT 1 FROM Color
FILTER (Color EQ Red OR Color EQ Blue OR Color EQ Yellow) AND Color NE Green AS Color`,
},
}
for _, tc := range testCases {
var p PlacementPolicy
require.NoError(t, p.DecodeString(tc.input))
var sb strings.Builder
require.NoError(t, p.WriteStringTo(&sb))
if tc.output == "" {
require.Equal(t, tc.input, sb.String())
} else {
require.Equal(t, tc.output, sb.String())
var p1 PlacementPolicy
require.NoError(t, p1.DecodeString(tc.output))
require.Equal(t, p, p1)
}
}
}
func TestDecodeSelectFilterExpr(t *testing.T) {
for _, s := range []string{
"SELECT 1 FROM *",