add fallback

Signed-off-by: cwen0 <[email protected]>

.gitignore

@@ -0,0 +1,2 @@
+vendor
+.idea

README.md

@@ -1,7 +1,7 @@
 vfsgen
 ======
 
-[![Build Status](https://travis-ci.org/shurcooL/vfsgen.svg?branch=master)](https://travis-ci.org/shurcooL/vfsgen) [![GoDoc](https://godoc.org/github.com/shurcooL/vfsgen?status.svg)](https://godoc.org/github.com/shurcooL/vfsgen)
+[![Build Status](https://travis-ci.org/cwen0/vfsgen.svg?branch=master)](https://travis-ci.org/cwen0/vfsgen) [![GoDoc](https://godoc.org/github.com/cwen0/vfsgen?status.svg)](https://godoc.org/github.com/cwen0/vfsgen)
 
 Package vfsgen takes an http.FileSystem (likely at `go generate` time) and
 generates Go code that statically implements the provided http.FileSystem.
@@ -20,7 +20,7 @@ Installation
 ------------
 
 ```bash
-go get -u github.com/shurcooL/vfsgen
+go get -u github.com/cwen0/vfsgen
 ```
 
 Usage
@@ -104,7 +104,7 @@ import (
 	"log"
 
 	"example.com/project/data"
-	"github.com/shurcooL/vfsgen"
+	"github.com/cwen0/vfsgen"
 )
 
 func main() {
@@ -128,7 +128,7 @@ Note that "dev" build tag is used to access the source filesystem, and the outpu
 Make sure it's installed and available in your PATH.
 
 ```bash
-go get -u github.com/shurcooL/vfsgen/cmd/vfsgendev
+go get -u github.com/cwen0/vfsgen/cmd/vfsgendev
 ```
 
 Then the "//go:generate go run -tags=dev assets_generate.go" directive can be replaced with:
@@ -141,7 +141,7 @@ vfsgendev accesses the source variable using "dev" build tag, and generates an o
 
 ### Additional Embedded Information
 
-All compressed files implement [`httpgzip.GzipByter` interface](https://godoc.org/github.com/shurcooL/httpgzip#GzipByter) for efficient direct access to the internal compressed bytes:
+All compressed files implement [`httpgzip.GzipByter` interface](https://godoc.org/github.com/cwen0/httpgzip#GzipByter) for efficient direct access to the internal compressed bytes:
 
 ```Go
 // GzipByter is implemented by compressed files for
@@ -152,7 +152,7 @@ type GzipByter interface {
 }
 ```
 
-Files that have been determined to not be worth gzip compressing (their compressed size is larger than original) implement [`httpgzip.NotWorthGzipCompressing` interface](https://godoc.org/github.com/shurcooL/httpgzip#NotWorthGzipCompressing):
+Files that have been determined to not be worth gzip compressing (their compressed size is larger than original) implement [`httpgzip.NotWorthGzipCompressing` interface](https://godoc.org/github.com/cwen0/httpgzip#NotWorthGzipCompressing):
 
 ```Go
 // NotWorthGzipCompressing is implemented by files that were determined

cmd/vfsgendev/generate.go

@@ -20,7 +20,7 @@ var generateTemplate = template.Must(template.New("").Funcs(template.FuncMap{
 import (
 	"log"
 
-	"github.com/shurcooL/vfsgen"
+	"github.com/cwen0/vfsgen"
 
 	sourcepkg {{.ImportPath | quote}}
 )

generator.go

@@ -42,6 +42,7 @@ func Generate(input http.FileSystem, opt Options) error {
 		return err
 	}
 
+	toc.Fallback = opt.Fallback
 	err = t.ExecuteTemplate(buf, "Trailer", toc)
 	if err != nil {
 		return err
@@ -58,6 +59,9 @@ type toc struct {
 
 	HasCompressedFile bool // There's at least one compressedFile.
 	HasFile           bool // There's at least one uncompressed file.
+
+	// Fallback file that is served if no other is found
+	Fallback string
 }
 
 // fileInfo is a definition of a file.
@@ -288,7 +292,11 @@ func (fs vfsgen۰FS) Open(path string) (http.File, error) {
 	path = pathpkg.Clean("/" + path)
 	f, ok := fs[path]
 	if !ok {
-		return nil, &os.PathError{Op: "open", Path: path, Err: os.ErrNotExist}
+		{{ if .Fallback -}}
+		fallbackPath := pathpkg.Clean("/" + "{{.Fallback}}")
+		f = fs[fallbackPath]
+        {{- else -}}
+		return nil, &os.PathError{Op: "open", Path: path, Err: os.ErrNotExist}{{end}}
 	}
 
 	switch f := f.(type) {{"{"}}{{if .HasCompressedFile}}

generator_test.go

@@ -10,8 +10,8 @@ import (
 	"strings"
 	"testing"
 
+	"github.com/cwen0/vfsgen"
 	"github.com/shurcooL/httpfs/union"
-	"github.com/shurcooL/vfsgen"
 	"golang.org/x/tools/godoc/vfs/httpfs"
 	"golang.org/x/tools/godoc/vfs/mapfs"
 )

go.mod

@@ -0,0 +1,9 @@
+module github.com/cwen0/vfsgen
+
+go 1.13
+
+require (
+	github.com/shurcooL/httpfs v0.0.0-20190707220628-8d4bc4ba7749
+	github.com/shurcooL/httpgzip v0.0.0-20190720172056-320755c1c1b0
+	golang.org/x/tools v0.0.0-20200618031402-d15173dcc7e4
+)

go.sum

@@ -0,0 +1,24 @@
+github.com/shurcooL/httpfs v0.0.0-20190707220628-8d4bc4ba7749 h1:bUGsEnyNbVPw06Bs80sCeARAlK8lhwqGyi6UT8ymuGk=
+github.com/shurcooL/httpfs v0.0.0-20190707220628-8d4bc4ba7749/go.mod h1:ZY1cvUeJuFPAdZ/B6v7RHavJWZn2YPVFQ1OSXhCGOkg=
+github.com/shurcooL/httpgzip v0.0.0-20190720172056-320755c1c1b0 h1:mj/nMDAwTBiaCqMEs4cYCqF7pO6Np7vhy1D1wcQGz+E=
+github.com/shurcooL/httpgzip v0.0.0-20190720172056-320755c1c1b0/go.mod h1:919LwcH0M7/W4fcZ0/jy0qGght1GIhqyS/EgWGH2j5Q=
+github.com/yuin/goldmark v1.1.27/go.mod h1:3hX8gzYuyVAZsxl0MRgGTJEmQBFcNTphYh9decYSb74=
+golang.org/x/crypto v0.0.0-20190308221718-c2843e01d9a2/go.mod h1:djNgcEr1/C05ACkg1iLfiJU5Ep61QUkGW8qpdssI0+w=
+golang.org/x/crypto v0.0.0-20191011191535-87dc89f01550/go.mod h1:yigFU9vqHzYiE8UmvKecakEJjdnWj3jj499lnFckfCI=
+golang.org/x/mod v0.2.0/go.mod h1:s0Qsj1ACt9ePp/hMypM3fl4fZqREWJwdYDEqhRiZZUA=
+golang.org/x/net v0.0.0-20190404232315-eb5bcb51f2a3/go.mod h1:t9HGtf8HONx5eT2rtn7q6eTqICYqUVnKs3thJo3Qplg=
+golang.org/x/net v0.0.0-20190620200207-3b0461eec859/go.mod h1:z5CRVTTTmAJ677TzLLGU+0bjPO0LkuOLi4/5GtJWs/s=
+golang.org/x/net v0.0.0-20200226121028-0de0cce0169b h1:0mm1VjtFUOIlE1SbDlwjYaDxZVDP2S5ou6y0gSgXHu8=
+golang.org/x/net v0.0.0-20200226121028-0de0cce0169b/go.mod h1:z5CRVTTTmAJ677TzLLGU+0bjPO0LkuOLi4/5GtJWs/s=
+golang.org/x/sync v0.0.0-20190423024810-112230192c58/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
+golang.org/x/sync v0.0.0-20190911185100-cd5d95a43a6e/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
+golang.org/x/sys v0.0.0-20190215142949-d0b11bdaac8a/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
+golang.org/x/sys v0.0.0-20190412213103-97732733099d/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
+golang.org/x/text v0.3.0 h1:g61tztE5qeGQ89tm6NTjjM9VPIm088od1l6aSorWRWg=
+golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=
+golang.org/x/tools v0.0.0-20191119224855-298f0cb1881e/go.mod h1:b+2E5dAYhXwXZwtnZ6UAqBI28+e2cm9otk0dWdXHAEo=
+golang.org/x/tools v0.0.0-20200618031402-d15173dcc7e4 h1:xotC2PrtjSST30ilZLyawOqMNuVyq9ev3IlvoQwaZZ8=
+golang.org/x/tools v0.0.0-20200618031402-d15173dcc7e4/go.mod h1:EkVYQZoAsY45+roYkvgYkIh4xh/qjgUK9TdY2XT94GE=
+golang.org/x/xerrors v0.0.0-20190717185122-a985d3407aa7/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
+golang.org/x/xerrors v0.0.0-20191011141410-1b5146add898/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
+golang.org/x/xerrors v0.0.0-20191204190536-9bdfabe68543/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=

options.go

@@ -26,6 +26,9 @@ type Options struct {
 	// VariableComment is the comment of the http.FileSystem variable in the generated code.
 	// If left empty, it defaults to "{{.VariableName}} statically implements the virtual filesystem provided to vfsgen.".
 	VariableComment string
+
+	// Fallback file that is served if no other is found
+	Fallback string
 }
 
 // fillMissing sets default values for mandatory options that are left empty.

test/test_gen.go

@@ -6,7 +6,7 @@ import (
 	"log"
 	"net/http"
 
-	"github.com/shurcooL/vfsgen"
+	"github.com/cwen0/vfsgen"
 	"golang.org/x/tools/godoc/vfs/httpfs"
 	"golang.org/x/tools/godoc/vfs/mapfs"
 )