Add identifier referencer (#3)

.github/workflows/bench.yml

@@ -0,0 +1,69 @@
+name: bench
+on:
+  push:
+    tags:
+      - v*
+    branches:
+      - master
+      - main
+  pull_request:
+env:
+  GO111MODULE: "on"
+jobs:
+  bench:
+    strategy:
+      matrix:
+        go-version: [ 1.15.x ]
+    runs-on: ubuntu-latest
+    steps:
+      - name: Install Go
+        uses: actions/setup-go@v2
+        with:
+          go-version: ${{ matrix.go-version }}
+      - name: Checkout code
+        uses: actions/checkout@v2
+      - name: Restore vendor
+        uses: actions/cache@v2
+        with:
+          path: |
+            vendor
+          key: ${{ runner.os }}-go${{ matrix.go-version }}-vendor-${{ hashFiles('**/go.mod') }}
+      - name: Populate dependencies
+        run: |
+          (test -d vendor && echo vendor found) || (go mod vendor && du -sh vendor && du -sh ~/go/pkg/mod)
+      - name: Restore benchstat
+        uses: actions/cache@v2
+        with:
+          path: ~/go/bin/benchstat
+          key: ${{ runner.os }}-benchstat
+      - name: Restore base benchmark result
+        uses: actions/cache@v2
+        with:
+          path: |
+            bench-master.txt
+            bench-main.txt
+          # Use base sha for PR or new commit hash for master/main push in benchmark result key.
+          key: ${{ runner.os }}-bench-${{ (github.event.pull_request.base.sha != github.event.after) && github.event.pull_request.base.sha || github.event.after }}
+      - name: Benchmark
+        id: bench
+        run: |
+          export REF_NAME=${GITHUB_REF##*/}
+          BENCH_COUNT=5 make bench-run bench-stat
+          OUTPUT=$(make bench-stat)
+          OUTPUT="${OUTPUT//'%'/'%25'}"
+          OUTPUT="${OUTPUT//$'\n'/'%0A'}"
+          OUTPUT="${OUTPUT//$'\r'/'%0D'}"
+          echo "::set-output name=result::$OUTPUT"
+      - name: Comment Benchmark Result
+        uses: marocchino/sticky-pull-request-comment@v2
+        with:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+          header: bench
+          message: |
+            ### Benchmark Result
+            <details><summary>Benchmark diff with base branch</summary>
+
+            ```
+            ${{ steps.bench.outputs.result }}
+            ```
+            </details>

.github/workflows/golangci-lint.yml

@@ -17,7 +17,7 @@ jobs:
         uses: golangci/golangci-lint-action@v2.3.0
         with:
           # Required: the version of golangci-lint is required and must be specified without patch version: we always use the latest patch version.
-          version: v1.32.2
+          version: v1.34.1
 
           # Optional: golangci-lint command line arguments.
           # args: ./the-only-dir-to-analyze/...

.github/workflows/test-unit.yml

@@ -0,0 +1,75 @@
+name: test-unit
+on:
+  push:
+    branches:
+      - master
+      - main
+  pull_request:
+env:
+  GO111MODULE: "on"
+jobs:
+  test:
+    strategy:
+      matrix:
+        go-version: [ 1.13.x, 1.14.x, 1.15.x ]
+    runs-on: ubuntu-latest
+    steps:
+      - name: Install Go
+        uses: actions/setup-go@v2
+        with:
+          go-version: ${{ matrix.go-version }}
+      - name: Checkout code
+        uses: actions/checkout@v2
+      - name: Restore base test coverage
+        uses: actions/cache@v2
+        with:
+          path: |
+            unit-base.txt
+          # Use base sha for PR or new commit hash for master/main push in test result key.
+          key: ${{ runner.os }}-unit-test-coverage-${{ (github.event.pull_request.base.sha != github.event.after) && github.event.pull_request.base.sha || github.event.after }}
+      - name: Restore vendor
+        uses: actions/cache@v2
+        with:
+          path: |
+            vendor
+          key: ${{ runner.os }}-go${{ matrix.go-version }}-vendor-${{ hashFiles('**/go.mod') }}
+      - name: Populate dependencies
+        run: |
+          (test -d vendor && echo vendor found) || (go mod vendor && du -sh vendor && du -sh ~/go/pkg/mod)
+      - name: Test
+        id: test
+        run: |
+          make test-unit
+          go tool cover -func=./unit.coverprofile | sed -e 's/.go:[0-9]*:\t/.go\t/g' | sed -e 's/\t\t*/\t/g'  > unit.txt
+          OUTPUT=$(test -e unit-base.txt && (diff unit-base.txt unit.txt || exit 0) || cat unit.txt)
+          OUTPUT="${OUTPUT//'%'/'%25'}"
+          OUTPUT="${OUTPUT//$'\n'/'%0A'}"
+          OUTPUT="${OUTPUT//$'\r'/'%0D'}"
+          TOTAL=$(grep 'total:' unit.txt)
+          echo "::set-output name=diff::$OUTPUT"
+          echo "::set-output name=total::$TOTAL"
+      - name: Store base coverage
+        if: ${{ github.ref == 'refs/heads/master' || github.ref == 'refs/heads/main' }}
+        run: cp unit.txt unit-base.txt
+      - name: Comment Test Coverage
+        if: matrix.go-version == '1.15.x'
+        uses: marocchino/sticky-pull-request-comment@v2
+        with:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+          header: unit-test
+          message: |
+            ### Unit Test Coverage
+            ${{ steps.test.outputs.total }}
+            <details><summary>Coverage diff with base branch</summary>
+
+            ```diff
+            ${{ steps.test.outputs.diff }}
+            ```
+            </details>
+
+      - name: Upload code coverage
+        if: matrix.go-version == '1.15.x'
+        uses: codecov/codecov-action@v1
+        with:
+          file: ./unit.coverprofile
+          flags: unittests

Makefile

@@ -1,5 +1,3 @@
-GOLANGCI_LINT_VERSION := "v1.32.2"
-
 # The head of Makefile determines location of dev-go to include standard targets.
 GO ?= go
 export GO111MODULE = on
@@ -29,6 +27,7 @@ endif
 
 -include $(DEVGO_PATH)/makefiles/main.mk
 -include $(DEVGO_PATH)/makefiles/test-unit.mk
+-include $(DEVGO_PATH)/makefiles/bench.mk
 -include $(DEVGO_PATH)/makefiles/lint.mk
 -include $(DEVGO_PATH)/makefiles/github-actions.mk
 

README.md

@@ -11,7 +11,9 @@ This module integrates [`github.com/Masterminds/squirrel`](https://github.com/Ma
 and [`github.com/jmoiron/sqlx`](https://github.com/jmoiron/sqlx) to allow seamless operation based on field tags of row
 structure.
 
-## Example
+Field tags (`db` by default) act as a source of truth for column names to allow better maintainability and fewer errors.
+
+## Simple CRUD
 
 ```go
 var (
@@ -72,4 +74,58 @@ _, err = s.Exec(ctx, s.DeleteStmt(tableName).Where(Product{ID: 2}, sqluct.SkipZe
 if err != nil {
     log.Fatal(err)
 }
+```
+
+## Referencing Fields In Complex Statements
+
+```go
+type User struct {
+    ID        int    `db:"id"`
+    FirstName string `db:"first_name"`
+    LastName  string `db:"last_name"`
+}
+
+type DirectReport struct {
+    ManagerID  int `db:"manager_id"`
+    EmployeeID int `db:"employee_id"`
+}
+
+var s sqluct.Storage
+
+rf := s.Ref()
+
+// Add aliased tables as pointers to structs.
+manager := &User{}
+rf.AddTableAlias(manager, "manager")
+
+employee := &User{}
+rf.AddTableAlias(employee, "employee")
+
+dr := &DirectReport{}
+rf.AddTableAlias(dr, "dr")
+
+// Find direct reports that share same last name and manager is not named John.
+qb := squirrel.StatementBuilder.Select(rf.Fmt("%s, %s", &dr.ManagerID, &dr.EmployeeID)).
+    From(rf.Fmt("%s AS %s", rf.Q("users"), manager)). // Quote literal name and alias it with registered struct pointer.
+    InnerJoin(rf.Fmt("%s AS %s ON %s = %s AND %s = %s",
+        rf.Q("direct_reports"), dr,
+        &dr.ManagerID, &manager.ID, // Identifiers are resolved using row field pointers.
+        &dr.EmployeeID, &employee.ID)).
+    Where(rf.Fmt("%s = %s", &manager.LastName, &employee.LastName)).
+    Where(rf.Fmt("%s != ?", &manager.FirstName), "John") // Regular binds work same way as in standard squirrel.
+
+stmt, args, err := qb.ToSql()
+if err != nil {
+    log.Fatal(err)
+}
+
+fmt.Println(stmt)
+fmt.Println(args)
+
+// SELECT dr.manager_id, dr.employee_id 
+// FROM users AS manager 
+// INNER JOIN direct_reports AS dr ON dr.manager_id = manager.id AND dr.employee_id = employee.id 
+// WHERE manager.last_name = employee.last_name AND manager.first_name != ?
+//
+// [John]
 ```

example_referencer_test.go

@@ -0,0 +1,55 @@
+package sqluct_test
+
+import (
+	"fmt"
+	"log"
+
+	"github.com/Masterminds/squirrel"
+	"github.com/bool64/sqluct"
+)
+
+func ExampleReferencer_Fmt() {
+	type User struct {
+		ID        int    `db:"id"`
+		FirstName string `db:"first_name"`
+		LastName  string `db:"last_name"`
+	}
+
+	type DirectReport struct {
+		ManagerID  int `db:"manager_id"`
+		EmployeeID int `db:"employee_id"`
+	}
+
+	rf := sqluct.Referencer{}
+
+	manager := &User{}
+	rf.AddTableAlias(manager, "manager")
+
+	employee := &User{}
+	rf.AddTableAlias(employee, "employee")
+
+	dr := &DirectReport{}
+	rf.AddTableAlias(dr, "dr")
+
+	// Find direct reports that share same last name and manager is not named John.
+	qb := squirrel.StatementBuilder.Select(rf.Fmt("%s, %s", &dr.ManagerID, &dr.EmployeeID)).
+		From(rf.Fmt("%s AS %s", rf.Q("users"), manager)).
+		InnerJoin(rf.Fmt("%s AS %s ON %s = %s AND %s = %s",
+			rf.Q("direct_reports"), dr,
+			&dr.ManagerID, &manager.ID,
+			&dr.EmployeeID, &employee.ID)).
+		Where(rf.Fmt("%s = %s", &manager.LastName, &employee.LastName)).
+		Where(rf.Fmt("%s != ?", &manager.FirstName), "John")
+
+	stmt, args, err := qb.ToSql()
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	fmt.Println(stmt)
+	fmt.Println(args)
+
+	// Output:
+	// SELECT dr.manager_id, dr.employee_id FROM users AS manager INNER JOIN direct_reports AS dr ON dr.manager_id = manager.id AND dr.employee_id = employee.id WHERE manager.last_name = employee.last_name AND manager.first_name != ?
+	// [John]
+}

go.mod

@@ -1,12 +1,12 @@
 module github.com/bool64/sqluct
 
-go 1.15
+go 1.13
 
 require (
 	github.com/DATA-DOG/go-sqlmock v1.5.0
 	github.com/Masterminds/squirrel v1.5.0
 	github.com/bool64/ctxd v0.1.3
-	github.com/bool64/dev v0.1.10
+	github.com/bool64/dev v0.1.12
 	github.com/jmoiron/sqlx v1.2.0
 	github.com/stretchr/testify v1.6.1
 	google.golang.org/appengine v1.6.7 // indirect

go.sum

@@ -7,6 +7,8 @@ github.com/bool64/ctxd v0.1.3/go.mod h1:rhUkoNE4mKFSJmo9l+78u2j+FVQifRCj0MHRhyZ2
 github.com/bool64/dev v0.1.0/go.mod h1:pn52JC52uSgpazChx9CeXyG+S3sW2V36HHoLNBbscdg=
 github.com/bool64/dev v0.1.10 h1:4L6eLD+qo1QgWDy+Y7OhJxi/gLwOAuV1rd07noMc3dU=
 github.com/bool64/dev v0.1.10/go.mod h1:pn52JC52uSgpazChx9CeXyG+S3sW2V36HHoLNBbscdg=
+github.com/bool64/dev v0.1.12 h1:mbuWBtCtOGwqt2lN1/9oPmn70XaOHdv2YHzQ31Zf9ks=
+github.com/bool64/dev v0.1.12/go.mod h1:pn52JC52uSgpazChx9CeXyG+S3sW2V36HHoLNBbscdg=
 github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
 github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=

mapper.go

@@ -274,6 +274,30 @@ func (sm *Mapper) FindColumnName(structPtr, fieldPtr interface{}) (string, error
 	return "", errFieldNotFound
 }
 
+// FindColumnNames returns column names mapped by a pointer to a field.
+func (sm *Mapper) FindColumnNames(structPtr interface{}) (map[interface{}]string, error) {
+	if structPtr == nil {
+		return nil, errNilArgument
+	}
+
+	v := reflect.Indirect(reflect.ValueOf(structPtr))
+	t := v.Type()
+
+	if !v.CanAddr() {
+		return nil, errNotAPointer
+	}
+
+	res := make(map[interface{}]string)
+
+	tm := sm.reflectMapper().TypeMap(t)
+	for _, fi := range tm.Index {
+		fv := reflectx.FieldByIndexesReadOnly(v, fi.Index)
+		res[fv.Addr().Interface()] = fi.Name
+	}
+
+	return res, nil
+}
+
 // Col will try to find column name and will panic on error.
 func (sm *Mapper) Col(structPtr, fieldPtr interface{}) string {
 	name, err := sm.FindColumnName(structPtr, fieldPtr)