1 files changed, 129 insertions, 0 deletions
diff --git a/tools/checklocks/annotations.go b/tools/checklocks/annotations.go
new file mode 100644
index 000000000..371260980
--- /dev/null
+++ b/tools/checklocks/annotations.go
@@ -0,0 +1,129 @@
+// Copyright 2020 The gVisor Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package checklocks
+
+import (
+	"fmt"
+
+	"go/token"
+	"strconv"
+	"strings"
+)
+
+const (
+	checkLocksAnnotation  = "// +checklocks:"
+	checkLocksAcquires    = "// +checklocksacquire:"
+	checkLocksReleases    = "// +checklocksrelease:"
+	checkLocksIgnore      = "// +checklocksignore"
+	checkLocksForce       = "// +checklocksforce"
+	checkLocksFail        = "// +checklocksfail"
+	checkAtomicAnnotation = "// +checkatomic"
+)
+
+// failData indicates an expected failure.
+type failData struct {
+	pos   token.Pos
+	count int
+	seen  int
+}
+
+// positionKey is a simple position string.
+type positionKey string
+
+// positionKey converts from a token.Pos to a key we can use to track failures
+// as the position of the failure annotation is not the same as the position of
+// the actual failure (different column/offsets). Hence we ignore these fields
+// and only use the file/line numbers to track failures.
+func (pc *passContext) positionKey(pos token.Pos) positionKey {
+	position := pc.pass.Fset.Position(pos)
+	return positionKey(fmt.Sprintf("%s:%d", position.Filename, position.Line))
+}
+
+// addFailures adds an expected failure.
+func (pc *passContext) addFailures(pos token.Pos, s string) {
+	count := 1
+	if len(s) > 0 && s[0] == ':' {
+		parsedCount, err := strconv.Atoi(s[1:])
+		if err != nil {
+			pc.pass.Reportf(pos, "unable to parse failure annotation %q: %v", s[1:], err)
+			return
+		}
+		count = parsedCount
+	}
+	pc.failures[pc.positionKey(pos)] = &failData{
+		pos:   pos,
+		count: count,
+	}
+}
+
+// addExemption adds an exemption.
+func (pc *passContext) addExemption(pos token.Pos) {
+	pc.exemptions[pc.positionKey(pos)] = struct{}{}
+}
+
+// addForce adds a force annotation.
+func (pc *passContext) addForce(pos token.Pos) {
+	pc.forced[pc.positionKey(pos)] = struct{}{}
+}
+
+// maybeFail checks a potential failure against a specific failure map.
+func (pc *passContext) maybeFail(pos token.Pos, fmtStr string, args ...interface{}) {
+	if fd, ok := pc.failures[pc.positionKey(pos)]; ok {
+		fd.seen++
+		return
+	}
+	if _, ok := pc.exemptions[pc.positionKey(pos)]; ok {
+		return // Ignored, not counted.
+	}
+	pc.pass.Reportf(pos, fmtStr, args...)
+}
+
+// checkFailure checks for the expected failure counts.
+func (pc *passContext) checkFailures() {
+	for _, fd := range pc.failures {
+		if fd.count != fd.seen {
+			// We are missing expect failures, report as much as possible.
+			pc.pass.Reportf(fd.pos, "got %d failures, want %d failures", fd.seen, fd.count)
+		}
+	}
+}
+
+// extractAnnotations extracts annotations from text.
+func (pc *passContext) extractAnnotations(s string, fns map[string]func(p string)) {
+	for prefix, fn := range fns {
+		if strings.HasPrefix(s, prefix) {
+			fn(s[len(prefix):])
+		}
+	}
+}
+
+// extractLineFailures extracts all line-based exceptions.
+//
+// Note that this applies only to individual line exemptions, and does not
+// consider function-wide exemptions, or specific field exemptions, which are
+// extracted separately as part of the saved facts for those objects.
+func (pc *passContext) extractLineFailures() {
+	for _, f := range pc.pass.Files {
+		for _, cg := range f.Comments {
+			for _, c := range cg.List {
+				pc.extractAnnotations(c.Text, map[string]func(string){
+					checkLocksFail:   func(p string) { pc.addFailures(c.Pos(), p) },
+					checkLocksIgnore: func(string) { pc.addExemption(c.Pos()) },
+					checkLocksForce:  func(string) { pc.addForce(c.Pos()) },
+				})
+			}
+		}
+	}
+}