diff options
Diffstat (limited to 'vendor/golang.org/x/tools/go/loader/util.go')
-rw-r--r-- | vendor/golang.org/x/tools/go/loader/util.go | 124 |
1 files changed, 124 insertions, 0 deletions
diff --git a/vendor/golang.org/x/tools/go/loader/util.go b/vendor/golang.org/x/tools/go/loader/util.go new file mode 100644 index 00000000..7f38dd74 --- /dev/null +++ b/vendor/golang.org/x/tools/go/loader/util.go @@ -0,0 +1,124 @@ +// Copyright 2013 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +package loader + +import ( + "go/ast" + "go/build" + "go/parser" + "go/token" + "io" + "os" + "strconv" + "sync" + + "golang.org/x/tools/go/buildutil" +) + +// We use a counting semaphore to limit +// the number of parallel I/O calls per process. +var ioLimit = make(chan bool, 10) + +// parseFiles parses the Go source files within directory dir and +// returns the ASTs of the ones that could be at least partially parsed, +// along with a list of I/O and parse errors encountered. +// +// I/O is done via ctxt, which may specify a virtual file system. +// displayPath is used to transform the filenames attached to the ASTs. +// +func parseFiles(fset *token.FileSet, ctxt *build.Context, displayPath func(string) string, dir string, files []string, mode parser.Mode) ([]*ast.File, []error) { + if displayPath == nil { + displayPath = func(path string) string { return path } + } + var wg sync.WaitGroup + n := len(files) + parsed := make([]*ast.File, n) + errors := make([]error, n) + for i, file := range files { + if !buildutil.IsAbsPath(ctxt, file) { + file = buildutil.JoinPath(ctxt, dir, file) + } + wg.Add(1) + go func(i int, file string) { + ioLimit <- true // wait + defer func() { + wg.Done() + <-ioLimit // signal + }() + var rd io.ReadCloser + var err error + if ctxt.OpenFile != nil { + rd, err = ctxt.OpenFile(file) + } else { + rd, err = os.Open(file) + } + if err != nil { + errors[i] = err // open failed + return + } + + // ParseFile may return both an AST and an error. + parsed[i], errors[i] = parser.ParseFile(fset, displayPath(file), rd, mode) + rd.Close() + }(i, file) + } + wg.Wait() + + // Eliminate nils, preserving order. + var o int + for _, f := range parsed { + if f != nil { + parsed[o] = f + o++ + } + } + parsed = parsed[:o] + + o = 0 + for _, err := range errors { + if err != nil { + errors[o] = err + o++ + } + } + errors = errors[:o] + + return parsed, errors +} + +// scanImports returns the set of all import paths from all +// import specs in the specified files. +func scanImports(files []*ast.File) map[string]bool { + imports := make(map[string]bool) + for _, f := range files { + for _, decl := range f.Decls { + if decl, ok := decl.(*ast.GenDecl); ok && decl.Tok == token.IMPORT { + for _, spec := range decl.Specs { + spec := spec.(*ast.ImportSpec) + + // NB: do not assume the program is well-formed! + path, err := strconv.Unquote(spec.Path.Value) + if err != nil { + continue // quietly ignore the error + } + if path == "C" { + continue // skip pseudopackage + } + imports[path] = true + } + } + } + } + return imports +} + +// ---------- Internal helpers ---------- + +// TODO(adonovan): make this a method: func (*token.File) Contains(token.Pos) +func tokenFileContainsPos(f *token.File, pos token.Pos) bool { + p := int(pos) + base := f.Base() + return base <= p && p < base+f.Size() +} |