github.com/hasnat/dolt/go@v0.0.0-20210628190320-9eb5d843fbb7/libraries/doltcore/sqle/dfunctions/active_branch.go (about)

     1  // Copyright 2021 Dolthub, Inc.
     2  //
     3  // Licensed under the Apache License, Version 2.0 (the "License");
     4  // you may not use this file except in compliance with the License.
     5  // You may obtain a copy of the License at
     6  //
     7  //     http://www.apache.org/licenses/LICENSE-2.0
     8  //
     9  // Unless required by applicable law or agreed to in writing, software
    10  // distributed under the License is distributed on an "AS IS" BASIS,
    11  // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    12  // See the License for the specific language governing permissions and
    13  // limitations under the License.
    14  
    15  package dfunctions
    16  
    17  import (
    18  	"fmt"
    19  
    20  	"github.com/dolthub/go-mysql-server/sql"
    21  
    22  	"github.com/dolthub/dolt/go/libraries/doltcore/ref"
    23  	"github.com/dolthub/dolt/go/libraries/doltcore/sqle"
    24  )
    25  
    26  const ActiveBranchFuncName = "active_branch"
    27  
    28  type ActiveBranchFunc struct {
    29  }
    30  
    31  // NewActiveBranchFunc creates a new ActiveBranchFunc expression.
    32  func NewActiveBranchFunc(ctx *sql.Context) sql.Expression {
    33  	return &ActiveBranchFunc{}
    34  }
    35  
    36  // Eval implements the Expression interface.
    37  func (cf *ActiveBranchFunc) Eval(ctx *sql.Context, row sql.Row) (interface{}, error) {
    38  	dbName := ctx.GetCurrentDatabase()
    39  	dSess := sqle.DSessFromSess(ctx.Session)
    40  
    41  	ddb, ok := dSess.GetDoltDB(dbName)
    42  
    43  	if !ok {
    44  		return nil, sql.ErrDatabaseNotFound.New(dbName)
    45  	}
    46  
    47  	rsr, ok := dSess.GetDoltDBRepoStateReader(dbName)
    48  
    49  	if !ok {
    50  		return nil, sql.ErrDatabaseNotFound.New(dbName)
    51  	}
    52  
    53  	currentBranch := rsr.CWBHeadRef()
    54  
    55  	branches, err := ddb.GetBranches(ctx)
    56  
    57  	if err != nil {
    58  		return nil, err
    59  	}
    60  
    61  	for _, br := range branches {
    62  		if ref.Equals(br, currentBranch) {
    63  			return br.GetPath(), nil
    64  		}
    65  	}
    66  
    67  	return nil, fmt.Errorf("active branch not found")
    68  }
    69  
    70  // String implements the Stringer interface.
    71  func (cf *ActiveBranchFunc) String() string {
    72  	return fmt.Sprint("ACTIVE_BRANCH()")
    73  }
    74  
    75  // IsNullable implements the Expression interface.
    76  func (cf *ActiveBranchFunc) IsNullable() bool {
    77  	return false
    78  }
    79  
    80  // Resolved implements the Expression interface.
    81  func (*ActiveBranchFunc) Resolved() bool {
    82  	return true
    83  }
    84  
    85  func (cf *ActiveBranchFunc) Type() sql.Type {
    86  	return sql.Text
    87  }
    88  
    89  // Children implements the Expression interface.
    90  func (*ActiveBranchFunc) Children() []sql.Expression {
    91  	return nil
    92  }
    93  
    94  // WithChildren implements the Expression interface.
    95  func (v *ActiveBranchFunc) WithChildren(ctx *sql.Context, children ...sql.Expression) (sql.Expression, error) {
    96  	if len(children) != 0 {
    97  		return nil, sql.ErrInvalidChildrenNumber.New(v, len(children), 0)
    98  	}
    99  	return NewActiveBranchFunc(ctx), nil
   100  }