5 files changed, 66 insertions, 9 deletions
diff --git a/internal/cond/compile.go b/internal/cond/compile.go
index 590d61a..94118ac 100644
--- a/internal/cond/compile.go
+++ b/internal/cond/compile.go
@@ -266,6 +266,7 @@ func (c *compiler) compileContent(n *sexp.Node) *node {
 			continue
 		}
 		keywords = append(keywords, keyword{norm: normed, src: a.Text})
+		c.cond.Keywords = append(c.cond.Keywords, Keyword{Opt: c.opt, Norm: normed})
 	}
 	if bad {
 		return nil
diff --git a/internal/cond/compile_test.go b/internal/cond/compile_test.go
index 2a07ad6..8432365 100644
--- a/internal/cond/compile_test.go
+++ b/internal/cond/compile_test.go
@@ -165,3 +165,24 @@ func TestGroupsMatchSpec(t *testing.T) {
 		}
 	}
 }
+
+// TestCompileCollectsKeywords: every content keyword is recorded as
+// compared, normalised under the compile options, and its key names those
+// options.
+func TestCompileCollectsKeywords(t *testing.T) {
+	opt := Options{IgnoreCase: true, Fold: true}
+	c, errs := Compile("d.conf", nodes(t, `(or (content "Spółka" "x") (not (content "NIP")))`), opt)
+	if len(errs) > 0 {
+		t.Fatal(errs)
+	}
+	want := []Keyword{{Opt: opt, Norm: "spolka"}, {Opt: opt, Norm: "x"}, {Opt: opt, Norm: "nip"}}
+	if !reflect.DeepEqual(c.Keywords, want) {
+		t.Errorf("Keywords = %+v, want %+v", c.Keywords, want)
+	}
+	if got := want[0].Key(); got != "if:spolka" {
+		t.Errorf("Key = %q", got)
+	}
+	if got := KeywordKey(Options{}, "NIP"); got != "sn:NIP" {
+		t.Errorf("strict, unfolded key = %q", got)
+	}
+}
diff --git a/internal/cond/eval.go b/internal/cond/eval.go
index e3093af..3cec110 100644
--- a/internal/cond/eval.go
+++ b/internal/cond/eval.go
@@ -19,7 +19,10 @@ type Facts interface {
 	Size() int64
 	ModTime() time.Time
 	Now() time.Time
-	Content(ignoreCase, fold bool) (string, error) // normalised with norm.Text
+	// ContentContains reports the index of the first of keywords, each
+	// normalised under opt with norm.Text, that the file's text contains, or
+	// -1 when it contains none.
+	ContentContains(opt Options, keywords []string) (int, error)
 	Duplicate(dirs []string) (original string, ok bool, err error)
 	Matched() bool // an earlier rule matched this file
 }
@@ -167,14 +170,16 @@ func (c *Cond) evalLeaf(n *node, f Facts) (ok bool, reason, warn string, caps []
 		return false, "", "", nil
 
 	case kContent:
-		text, err := f.Content(c.opt.IgnoreCase, c.opt.Fold)
+		norms := make([]string, len(n.keywords))
+		for i, kw := range n.keywords {
+			norms[i] = kw.norm
+		}
+		i, err := f.ContentContains(c.opt, norms)
 		if err != nil {
 			return false, "", "content unreadable: " + err.Error(), nil
 		}
-		for _, kw := range n.keywords {
-			if strings.Contains(text, kw.norm) {
-				return true, `content "` + kw.src + `"`, "", nil
-			}
+		if i >= 0 {
+			return true, `content "` + n.keywords[i].src + `"`, "", nil
 		}
 		return false, "", "", nil
 
diff --git a/internal/cond/eval_test.go b/internal/cond/eval_test.go
index 3607978..8891de7 100644
--- a/internal/cond/eval_test.go
+++ b/internal/cond/eval_test.go
@@ -37,12 +37,18 @@ func (f *fake) Size() int64        { return f.size }
 func (f *fake) ModTime() time.Time { return now.Add(-f.age) }
 func (f *fake) Now() time.Time     { return now }
 func (f *fake) Matched() bool      { return f.matched }
-func (f *fake) Content(ic, fold bool) (string, error) {
+func (f *fake) ContentContains(opt Options, keywords []string) (int, error) {
 	f.contentCalls++
 	if f.rawErr != nil {
-		return "", f.rawErr
+		return -1, f.rawErr
 	}
-	return norm.Text(f.raw, ic, fold), nil
+	text := norm.Text(f.raw, opt.IgnoreCase, opt.Fold)
+	for i, kw := range keywords {
+		if strings.Contains(text, kw) {
+			return i, nil
+		}
+	}
+	return -1, nil
 }
 func (f *fake) Duplicate(dirs []string) (string, bool, error) { return f.dupOrig, f.dupOK, nil }
 
diff --git a/internal/cond/types.go b/internal/cond/types.go
index 9455f63..28a4fc9 100644
--- a/internal/cond/types.go
+++ b/internal/cond/types.go
@@ -24,6 +24,30 @@ type Cond struct {
 	opt         Options    // the case/fold settings conditions were compiled with; Task 8 needs them again at eval time
 	UsesContent bool       // some content test exists
 	DupDirs     [][]string // the raw directory arguments of each duplicate test, in order
+	Keywords    []Keyword  // every content keyword, as compiled, in order
+}
+
+// Keyword is one content keyword as a content test compares it: normalised
+// under the options it was compiled with.
+type Keyword struct {
+	Opt  Options
+	Norm string
+}
+
+// Key is the keyword's identity across runs, for the keyword cache: its
+// options and its normalised text.
+func (k Keyword) Key() string { return KeywordKey(k.Opt, k.Norm) }
+
+// KeywordKey is Keyword.Key for opt and an already normalised keyword.
+func KeywordKey(opt Options, norm string) string {
+	b := []byte("sn:")
+	if opt.IgnoreCase {
+		b[0] = 'i'
+	}
+	if opt.Fold {
+		b[1] = 'f'
+	}
+	return string(b) + norm
 }
 
 // kind is what a compiled node tests, or how it combines its children.