Add optional context for certificate errors.

net/cert/internal/cert_error_params.cc

Index: net/cert/internal/cert_error_params.cc
diff --git a/net/cert/internal/cert_error_params.cc b/net/cert/internal/cert_error_params.cc
new file mode 100644
index 0000000000000000000000000000000000000000..08ddfca062d184ce9dfb9d70cb17ea7e2b4954b5
--- /dev/null
+++ b/net/cert/internal/cert_error_params.cc
@@ -0,0 +1,93 @@
+// Copyright 2016 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "net/cert/internal/cert_error_params.h"
+
+#include "base/memory/ptr_util.h"
+#include "base/strings/string_number_conversions.h"
+#include "net/der/input.h"
+
+namespace net {
+
+namespace {
+
+// Parameters subclass for describing (and pretty-printing) 1 or 2 DER
+// blobs. It makes a copy of the der::Inputs.
+class CertErrorParams2Der : public CertErrorParams {
+ public:
+  CertErrorParams2Der(const char* name1,
+                      const der::Input& der1,
+                      const char* name2,
+                      const der::Input& der2)
+      : name1_(name1),
+        der1_(der1.AsString()),
+        name2_(name2),
+        der2_(der2.AsString()) {}
+
+  std::string ToDebugString() const override {
+    std::string result;
+    AppendDer(name1_, der1_, &result);
+    if (name2_) {
+      result += "\n";
+      AppendDer(name2_, der2_, &result);
+    }
+    return result;
+  }
+
+ private:
+  static void AppendDer(const char* name,
+                        const std::string& der,
+                        std::string* out) {
+    *out += name;
+    *out += ": " + base::HexEncode(der.data(), der.size());
+  }
+
+  const char* name1_;
+  std::string der1_;
+
+  const char* name2_;
+  std::string der2_;
+};
+
+// Parameters subclass for describing (and pretty-printing) a single size_t.
+class CertErrorParamsSizeT : public CertErrorParams {
+ public:
+  CertErrorParamsSizeT(const char* name, size_t value)
+      : name_(name), value_(value) {}
+
+  std::string ToDebugString() const override {
+    return name_ + std::string(": ") + base::SizeTToString(value_);
+  }
+
+ private:
+  const char* name_;
+  size_t value_;
+};
+
+}  // namespace
+
+CertErrorParams::CertErrorParams() = default;
+CertErrorParams::~CertErrorParams() = default;
+
+std::unique_ptr<CertErrorParams> CreateCertErrorParams1Der(
+    const char* name1,
+    const der::Input& der1) {
+  return base::MakeUnique<CertErrorParams2Der>(name1, der1, nullptr,
+                                               der::Input());
+}
+
+std::unique_ptr<CertErrorParams> CreateCertErrorParams2Der(
+    const char* name1,
+    const der::Input& der1,
+    const char* name2,
+    const der::Input& der2) {
+  return base::MakeUnique<CertErrorParams2Der>(name1, der1, name2, der2);
+}
+
+std::unique_ptr<CertErrorParams> CreateCertErrorParamsSizeT(const char* name,
+                                                            size_t value) {
+  return base::MakeUnique<CertErrorParamsSizeT>(name, value);
+}
+
+}  // namespace net