initial commit

LICENSE

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+Copyright (c) 2013 Frederik Zipp. All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are
+met:
+
+   * Redistributions of source code must retain the above copyright
+notice, this list of conditions and the following disclaimer.
+   * Redistributions in binary form must reproduce the above
+copyright notice, this list of conditions and the following disclaimer
+in the documentation and/or other materials provided with the
+distribution.
+   * Neither the name of the copyright owner nor the names of its
+contributors may be used to endorse or promote products derived from
+this software without specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

README.md

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+Gocyclo calculates cyclomatic complexities of functions in Go source code.
+
+The cyclomatic complexity of a function is calculated according to the
+following rules:
+
+     1 is the base complexity of a function
+    +1 for each 'if', 'for', 'case', '&&' or '||'
+
+To install, run
+
+    $ go get github.com/fzipp/gocyclo
+
+and put the resulting binary in one of your PATH directories if
+`$GOPATH/bin` isn't already in your PATH.
+
+Usage:
+
+    $ gocyclo [<flag> ...] <Go file or directory> ...
+
+Examples:
+
+    $ gocyclo .
+    $ gocyclo main.go
+    $ gocyclo -top 10 src/
+    $ gocyclo -over 25 docker
+
+The output fields for each line are:
+
+    <complexity> <package> <function> <file:row:column>
+

gocyclo.go

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+// Copyright 2013 Frederik Zipp. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Gocyclo calculates the cyclomatic complexities of functions and
+// methods in Go source code.
+//
+// Usage:
+//      gocyclo [<flag> ...] <Go file or directory> ...
+//
+// Flags
+//      -over N   show functions with complexity > N only and
+//                return exit code 1 if the output is non-empty
+//      -top N    show the top N most complex functions only
+//      -avg      show the average complexity
+//
+// The output fields for each line are:
+// <complexity> <package> <function> <file:row:column>
+package main
+
+import (
+	"flag"
+	"fmt"
+	"go/ast"
+	"go/parser"
+	"go/token"
+	"io"
+	"os"
+	"path/filepath"
+	"sort"
+	"strings"
+)
+
+const usageDoc = `Calculate cyclomatic complexities of Go functions.
+usage:
+        gocyclo [<flag> ...] <Go file or directory> ...
+
+Flags
+        -over N   show functions with complexity > N only and
+                  return exit code 1 if the set is non-empty
+        -top N    show the top N most complex functions only
+        -avg      show the average complexity over all functions,
+		          not depending on whether -over or -top are set
+
+The output fields for each line are:
+<complexity> <package> <function> <file:row:column>
+`
+
+func usage() {
+	fmt.Fprintf(os.Stderr, usageDoc)
+	os.Exit(2)
+}
+
+var (
+	over = flag.Int("over", 0, "show functions with complexity > N only")
+	top  = flag.Int("top", -1, "show the top N most complex functions only")
+	avg  = flag.Bool("avg", false, "show the average complexity")
+)
+
+func main() {
+	flag.Usage = usage
+	flag.Parse()
+	args := flag.Args()
+	if len(args) == 0 {
+		usage()
+	}
+
+	stats := analyze(args)
+	sort.Sort(byComplexity(stats))
+	written := writeStats(os.Stdout, stats)
+
+	if *avg {
+		showAverage(stats)
+	}
+
+	if *over > 0 && written > 0 {
+		os.Exit(1)
+	}
+}
+
+func analyze(paths []string) []stat {
+	stats := make([]stat, 0)
+	for _, path := range paths {
+		if isDir(path) {
+			stats = analyzeDir(path, stats)
+		} else {
+			stats = analyzeFile(path, stats)
+		}
+	}
+	return stats
+}
+
+func isDir(filename string) bool {
+	fi, err := os.Stat(filename)
+	return err == nil && fi.IsDir()
+}
+
+func analyzeFile(fname string, stats []stat) []stat {
+	fset := token.NewFileSet()
+	f, err := parser.ParseFile(fset, fname, nil, 0)
+	if err != nil {
+		exitError(err)
+	}
+	return buildStats(f, fset, stats)
+}
+
+func analyzeDir(dirname string, stats []stat) []stat {
+	filepath.Walk(dirname, func(path string, info os.FileInfo, err error) error {
+		if err == nil && !info.IsDir() && strings.HasSuffix(path, ".go") {
+			stats = analyzeFile(path, stats)
+		}
+		return err
+	})
+	return stats
+}
+
+func exitError(err error) {
+	fmt.Fprintln(os.Stderr, err)
+	os.Exit(1)
+}
+
+func writeStats(w io.Writer, sortedStats []stat) int {
+	for i, stat := range sortedStats {
+		if i == *top {
+			return i
+		}
+		if stat.Complexity <= *over {
+			return i
+		}
+		fmt.Fprintln(w, stat)
+	}
+	return len(sortedStats)
+}
+
+func showAverage(stats []stat) {
+	fmt.Printf("Average: %.3g\n", average(stats))
+}
+
+func average(stats []stat) float64 {
+	total := 0
+	for _, s := range stats {
+		total += s.Complexity
+	}
+	return float64(total) / float64(len(stats))
+}
+
+type stat struct {
+	PkgName    string
+	FuncName   string
+	Complexity int
+	Pos        token.Position
+}
+
+func (s stat) String() string {
+	return fmt.Sprintf("%d %s %s %s", s.Complexity, s.PkgName, s.FuncName, s.Pos)
+}
+
+type byComplexity []stat
+
+func (s byComplexity) Len() int      { return len(s) }
+func (s byComplexity) Swap(i, j int) { s[i], s[j] = s[j], s[i] }
+func (s byComplexity) Less(i, j int) bool {
+	return s[i].Complexity >= s[j].Complexity
+}
+
+func buildStats(f *ast.File, fset *token.FileSet, stats []stat) []stat {
+	for _, decl := range f.Decls {
+		if fn, ok := decl.(*ast.FuncDecl); ok {
+			stats = append(stats, stat{
+				PkgName:    f.Name.Name,
+				FuncName:   funcName(fn),
+				Complexity: complexity(fn),
+				Pos:        fset.Position(fn.Pos()),
+			})
+		}
+	}
+	return stats
+}
+
+// funcName returns the name representation of a function or method:
+// "(Type).Name" for methods or simply "Name" for functions.
+func funcName(fn *ast.FuncDecl) string {
+	if fn.Recv != nil {
+		typ := fn.Recv.List[0].Type
+		return fmt.Sprintf("(%s).%s", recvString(typ), fn.Name)
+	}
+	return fn.Name.Name
+}
+
+// recvString returns a string representation of recv of the
+// form "T", "*T", or "BADRECV" (if not a proper receiver type).
+func recvString(recv ast.Expr) string {
+	switch t := recv.(type) {
+	case *ast.Ident:
+		return t.Name
+	case *ast.StarExpr:
+		return "*" + recvString(t.X)
+	}
+	return "BADRECV"
+}
+
+// complexity calculates the cyclomatic complexity of a function.
+func complexity(fn *ast.FuncDecl) int {
+	v := complexityVisitor{}
+	ast.Walk(&v, fn)
+	return v.Complexity
+}
+
+type complexityVisitor struct {
+	// Complexity is the cyclomatic complexity
+	Complexity int
+}
+
+// Visit implements the ast.Visitor interface.
+func (v *complexityVisitor) Visit(n ast.Node) ast.Visitor {
+	switch n := n.(type) {
+	case *ast.FuncDecl, *ast.IfStmt, *ast.ForStmt, *ast.RangeStmt, *ast.CaseClause, *ast.CommClause:
+		v.Complexity++
+	case *ast.BinaryExpr:
+		if n.Op == token.LAND || n.Op == token.LOR {
+			v.Complexity++
+		}
+	}
+	return v
+}