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131 lines
3.5 KiB
131 lines
3.5 KiB
// Copyright (c) 2012-present The upper.io/db authors. All rights reserved.
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//
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// Permission is hereby granted, free of charge, to any person obtaining
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// a copy of this software and associated documentation files (the
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// "Software"), to deal in the Software without restriction, including
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// without limitation the rights to use, copy, modify, merge, publish,
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// distribute, sublicense, and/or sell copies of the Software, and to
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// permit persons to whom the Software is furnished to do so, subject to
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// the following conditions:
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//
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// The above copyright notice and this permission notice shall be
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// included in all copies or substantial portions of the Software.
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//
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// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
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// EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
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// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
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// NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
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// LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
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// OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
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// WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
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package db
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import (
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"fmt"
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"sort"
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"github.com/upper/db/v4/internal/adapter"
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)
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// LogicalExpr represents an expression to be used in logical statements.
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type LogicalExpr = adapter.LogicalExpr
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// LogicalOperator represents a logical operation.
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type LogicalOperator = adapter.LogicalOperator
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// Cond is a map that defines conditions for a query.
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//
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// Each entry of the map represents a condition (a column-value relation bound
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// by a comparison Operator). The comparison can be specified after the column
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// name, if no comparison operator is provided the equality operator is used as
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// default.
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//
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// Examples:
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//
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// // Age equals 18.
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// db.Cond{"age": 18}
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//
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// // Age is greater than or equal to 18.
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// db.Cond{"age >=": 18}
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//
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// // id is any of the values 1, 2 or 3.
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// db.Cond{"id IN": []{1, 2, 3}}
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//
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// // Age is lower than 18 (MongoDB syntax)
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// db.Cond{"age $lt": 18}
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//
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// // age > 32 and age < 35
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// db.Cond{"age >": 32, "age <": 35}
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type Cond map[interface{}]interface{}
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// Empty returns false if there are no conditions.
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func (c Cond) Empty() bool {
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for range c {
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return false
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}
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return true
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}
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// Constraints returns each one of the Cond map entires as a constraint.
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func (c Cond) Constraints() []adapter.Constraint {
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z := make([]adapter.Constraint, 0, len(c))
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for _, k := range c.keys() {
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z = append(z, adapter.NewConstraint(k, c[k]))
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}
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return z
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}
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// Operator returns the equality operator.
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func (c Cond) Operator() LogicalOperator {
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return adapter.DefaultLogicalOperator
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}
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func (c Cond) keys() []interface{} {
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keys := make(condKeys, 0, len(c))
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for k := range c {
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keys = append(keys, k)
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}
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if len(c) > 1 {
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sort.Sort(keys)
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}
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return keys
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}
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// Expressions returns all the expressions contained in the condition.
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func (c Cond) Expressions() []LogicalExpr {
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z := make([]LogicalExpr, 0, len(c))
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for _, k := range c.keys() {
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z = append(z, Cond{k: c[k]})
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}
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return z
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}
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type condKeys []interface{}
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func (ck condKeys) Len() int {
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return len(ck)
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}
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func (ck condKeys) Less(i, j int) bool {
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return fmt.Sprintf("%v", ck[i]) < fmt.Sprintf("%v", ck[j])
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}
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func (ck condKeys) Swap(i, j int) {
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ck[i], ck[j] = ck[j], ck[i]
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}
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func defaultJoin(in ...adapter.LogicalExpr) []adapter.LogicalExpr {
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for i := range in {
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cond, ok := in[i].(Cond)
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if ok && !cond.Empty() {
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in[i] = And(cond)
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}
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}
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return in
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}
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var (
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_ = LogicalExpr(Cond{})
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)
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