feat: add MimeParser with GMime and safe attachment naming

1 files changed, 171 insertions, 0 deletions

diff --git a/tests/test_mimeparser.cpp b/tests/test_mimeparser.cpp
new file mode 100644
index 0000000..72bdff7
--- /dev/null
+++ b/tests/test_mimeparser.cpp
@@ -0,0 +1,171 @@
+#include <QtTest>
+#include <QTemporaryDir>
+#include <QDir>
+#include "mimeparser.h"
+
+class TestMimeParser : public QObject
+{
+    Q_OBJECT
+private slots:
+    void initTestCase();
+
+    void parsesPlainText();
+    void prefersHtmlWhenAvailable();
+    void fallsBackToPlainWhenHtmlDisabled();
+    void collectsInlineCidParts();
+    void decodesQuotedPrintableAttachment();
+    void decodesEncodedHeaders();
+    void malformedMessageDoesNotCrash();
+    void missingFileIsReported();
+    void hostileFilenameIsSanitised();
+    void savedAttachmentMatchesBytes();
+
+private:
+    QString fixture(const QString &name) const
+    { return m_fixtureDir + QLatin1Char('/') + name; }
+
+    QString m_fixtureDir;
+};
+
+void TestMimeParser::initTestCase()
+{
+    // FIXTURE_DIR is defined by CMake so the test can run from any cwd.
+    m_fixtureDir = QStringLiteral(FIXTURE_DIR);
+    QVERIFY2(QDir(m_fixtureDir).exists(), "fixture directory missing");
+}
+
+void TestMimeParser::parsesPlainText()
+{
+    MimeParser parser;
+    const ParsedMessage msg = parser.parse(fixture(QStringLiteral("plain.eml")));
+
+    QVERIFY(msg.ok);
+    QCOMPARE(msg.subject, QStringLiteral("Plain hello"));
+    QCOMPARE(msg.from, QStringLiteral("Alice <alice@example.org>"));
+    QVERIFY(msg.plainBody.contains(QStringLiteral("Hello Bob.")));
+    QVERIFY(msg.htmlBody.isEmpty());
+    QVERIFY(msg.attachments.isEmpty());
+}
+
+void TestMimeParser::prefersHtmlWhenAvailable()
+{
+    MimeParser parser;
+    const ParsedMessage msg =
+        parser.parse(fixture(QStringLiteral("alternative.eml")));
+
+    QVERIFY(msg.ok);
+    QVERIFY(msg.htmlBody.contains(QStringLiteral("html version")));
+    // The plain alternative is kept so the user can toggle to it.
+    QVERIFY(msg.plainBody.contains(QStringLiteral("plain version")));
+    QVERIFY(msg.hasHtml());
+}
+
+void TestMimeParser::fallsBackToPlainWhenHtmlDisabled()
+{
+    MimeParser parser;
+    const ParsedMessage msg = parser.parse(fixture(QStringLiteral("plain.eml")));
+
+    QVERIFY(!msg.hasHtml());
+    QVERIFY(!msg.plainBody.isEmpty());
+}
+
+void TestMimeParser::collectsInlineCidParts()
+{
+    MimeParser parser;
+    const ParsedMessage msg =
+        parser.parse(fixture(QStringLiteral("inline_image.eml")));
+
+    QVERIFY(msg.ok);
+    QCOMPARE(msg.inlineParts.size(), 1);
+    // Content-ID angle brackets are stripped so it matches the cid: URL body.
+    QVERIFY(msg.inlineParts.contains(QStringLiteral("logo@example.org")));
+
+    const InlinePart part = msg.inlineParts.value(QStringLiteral("logo@example.org"));
+    QCOMPARE(part.mimeType, QStringLiteral("image/png"));
+    // Decoded 1x1 PNG starts with the PNG magic bytes.
+    QVERIFY(part.data.startsWith(QByteArray("\x89PNG", 4)));
+}
+
+void TestMimeParser::decodesQuotedPrintableAttachment()
+{
+    MimeParser parser;
+    const ParsedMessage msg =
+        parser.parse(fixture(QStringLiteral("attachment.eml")));
+
+    QVERIFY(msg.ok);
+    QCOMPARE(msg.attachments.size(), 1);
+    QCOMPARE(msg.attachments.first().filename, QStringLiteral("notes.txt"));
+    QCOMPARE(QString::fromUtf8(msg.attachments.first().data),
+             QStringLiteral("café notes"));
+}
+
+void TestMimeParser::decodesEncodedHeaders()
+{
+    MimeParser parser;
+    const ParsedMessage msg =
+        parser.parse(fixture(QStringLiteral("encoded_subject.eml")));
+
+    QVERIFY(msg.ok);
+    QCOMPARE(msg.subject, QStringLiteral("Café meeting"));
+    QVERIFY(msg.from.contains(QStringLiteral("Älice")));
+}
+
+void TestMimeParser::malformedMessageDoesNotCrash()
+{
+    MimeParser parser;
+    const ParsedMessage msg =
+        parser.parse(fixture(QStringLiteral("truncated.eml")));
+
+    // GMime is tolerant: it recovers the headers and whatever body it found.
+    // The requirement is only that parsing terminates and reports something.
+    QCOMPARE(msg.subject, QStringLiteral("Truncated"));
+}
+
+void TestMimeParser::missingFileIsReported()
+{
+    MimeParser parser;
+    const ParsedMessage msg =
+        parser.parse(fixture(QStringLiteral("does_not_exist.eml")));
+
+    QVERIFY(!msg.ok);
+    QVERIFY(!msg.error.isEmpty());
+}
+
+void TestMimeParser::hostileFilenameIsSanitised()
+{
+    MimeParser parser;
+    const ParsedMessage msg =
+        parser.parse(fixture(QStringLiteral("hostile_filename.eml")));
+
+    QVERIFY(msg.ok);
+    QCOMPARE(msg.attachments.size(), 1);
+
+    // The raw header value is preserved for display...
+    QVERIFY(msg.attachments.first().filename.contains(QStringLiteral("..")));
+    // ...but the name used on disk is reduced to a basename.
+    QCOMPARE(msg.attachments.first().safeFilename(), QStringLiteral("pwned.txt"));
+}
+
+void TestMimeParser::savedAttachmentMatchesBytes()
+{
+    MimeParser parser;
+    const ParsedMessage msg =
+        parser.parse(fixture(QStringLiteral("attachment.eml")));
+    QVERIFY(msg.ok);
+
+    QTemporaryDir dir;
+    QString error;
+    const QString written =
+        msg.attachments.first().saveTo(dir.path(), &error);
+
+    QVERIFY2(!written.isEmpty(), qPrintable(error));
+    // Never escapes the target directory.
+    QVERIFY(written.startsWith(dir.path()));
+
+    QFile f(written);
+    QVERIFY(f.open(QIODevice::ReadOnly));
+    QCOMPARE(f.readAll(), msg.attachments.first().data);
+}
+
+QTEST_MAIN(TestMimeParser)
+#include "test_mimeparser.moc"