golden/pdfxform a pdf rasterization server

go/pdf/pdfium.go

Index: go/pdf/pdfium.go
diff --git a/go/pdf/pdfium.go b/go/pdf/pdfium.go
new file mode 100644
index 0000000000000000000000000000000000000000..bd6c56e306d3c1918558e4cf19a1764cf8630ce3
--- /dev/null
+++ b/go/pdf/pdfium.go
@@ -0,0 +1,65 @@
+// PDF Rasterizer
+package pdf
+
+import (
+	"fmt"
+	"os"
+	"os/exec"
+	"path/filepath"
+	"time"
+
+	"go.skia.org/infra/go/fileutil"
+	"go.skia.org/infra/go/util"
+)
+
+const pdfiumExecutable = "pdfium_test"
+
+type Pdfium struct{}
+
+func (Pdfium) String() string { return "Pdfium" }
+
+func (Pdfium) Enabled() bool {
+	return commandFound(pdfiumExecutable)
+}
+
+// Rasterize assumes that filepath.Dir(pdfInputPath) is writable
+func (Pdfium) Rasterize(pdfInputPath, pngOutputPath string) error {
+	if !(Pdfium{}).Enabled() {
+		return fmt.Errorf("pdfium_test is missing")
+	}
+
+	// Check input
+	if !fileutil.FileExists(pdfInputPath) {
+		return fmt.Errorf("Path '%s' does not exist", pdfInputPath)
+	}
+
+	// Remove any files created by pdfiumExecutable
+	defer func() {
+		// Assume pdfInputPath has glob characters.
+		matches, _ := filepath.Glob(fmt.Sprintf("%s.*.png", pdfInputPath))
+		for _, match := range matches {
+			util.Remove(match)
+		}
+	}()
+
+	command := exec.Command(pdfiumExecutable, "--png", pdfInputPath)
+	if err := command.Start(); err != nil {
+		return err
+	}
+	go func() {
+		time.Sleep(5 * time.Second)
+		_ = command.Process.Kill()
+	}()
+	if err := command.Wait(); err != nil {
+		return err
+	}
+
+	firstPagePath := fmt.Sprintf("%s.0.png", pdfInputPath)
+	if !fileutil.FileExists(firstPagePath) {
+		return fmt.Errorf("First rasterized page (%s) not found.", firstPagePath)
+	}
+	if err := os.Rename(firstPagePath, pngOutputPath); err != nil {
+		return err
+	}
+	return nil
+}