feat: enhance preview command with indexed content validation

autotests/dfm-search-tests/CMakeLists.txt

@@ -29,6 +29,7 @@ target_sources(dfm-search-test PRIVATE
     ${CMAKE_SOURCE_DIR}/src/dfm-search/dfm-search-client/size_parser.cpp
     ${CMAKE_SOURCE_DIR}/src/dfm-search/dfm-search-client/time_parser.cpp
     ${CMAKE_SOURCE_DIR}/src/dfm-search/dfm-search-client/cli_options.cpp
+    ${CMAKE_SOURCE_DIR}/src/dfm-search/dfm-search-client/preview_command.cpp
     ${CMAKE_SOURCE_DIR}/src/dfm-search/dfm-search-client/preview_output_utils.cpp
     ${CMAKE_SOURCE_DIR}/src/dfm-search/dfm-search-client/output/output_formatter.h
     ${CMAKE_SOURCE_DIR}/src/dfm-search/dfm-search-client/output/text_output.cpp

autotests/dfm-search-tests/tst_content_retriever.cpp

@@ -96,6 +96,7 @@ private Q_SLOTS:
     void fetchPreview_noKeyword();
     void fetchPreview_withKeyword();
     void fetchPreview_keywordNotFound();
+    void fetchPreview_notIndexed();
     void fetchPreview_offsetBeyondContent();
     void fetchPreview_unlimitedNoKeyword();
     void previewSnippet_basic();
@@ -253,6 +254,7 @@ void tst_ContentRetriever::fetchPreview_noKeyword()
     const PreviewResult result = retriever.fetchPreview("/tmp/doc-a.txt",
                                                          SearchType::Content,
                                                          options);
+    QVERIFY(result.status() == PreviewStatus::Success);
     QCOMPARE(result.content(), QString("world"));
     QCOMPARE(result.charCount(), QString("hello world from content index").size());
     QCOMPARE(result.keywordOffset(), -1);
@@ -279,6 +281,7 @@ void tst_ContentRetriever::fetchPreview_withKeyword()
     const PreviewResult result = retriever.fetchPreview("/tmp/doc-a.txt",
                                                          SearchType::Content,
                                                          options);
+    QVERIFY(result.status() == PreviewStatus::Success);
     QCOMPARE(result.content(), QString("world from"));
     QCOMPARE(result.charCount(), QString("hello world from content index").size());
     QCOMPARE(result.keywordOffset(), 6);
@@ -305,11 +308,38 @@ void tst_ContentRetriever::fetchPreview_keywordNotFound()
     const PreviewResult result = retriever.fetchPreview("/tmp/doc-a.txt",
                                                          SearchType::Content,
                                                          options);
+    QVERIFY(result.status() == PreviewStatus::Success);
     QVERIFY(result.content().isEmpty());
     QCOMPARE(result.charCount(), QString("hello world from content index").size());
     QCOMPARE(result.keywordOffset(), -1);
 }
 
+void tst_ContentRetriever::fetchPreview_notIndexed()
+{
+    QTemporaryDir tempDir;
+    QVERIFY(tempDir.isValid());
+
+    const QString contentIndexDir = tempDir.path() + "/content-index";
+    createIndex(contentIndexDir, SearchType::Content);
+
+    ContentRetriever retriever;
+    retriever.setIndexDirectory(SearchType::Content, contentIndexDir);
+
+    const PreviewResult missingPathResult = retriever.fetchPreview("/tmp/missing.txt",
+                                                                   SearchType::Content);
+    QVERIFY(missingPathResult.status() == PreviewStatus::NotIndexed);
+    QVERIFY(missingPathResult.content().isEmpty());
+    QCOMPARE(missingPathResult.charCount(), 0);
+    QCOMPARE(missingPathResult.keywordOffset(), -1);
+
+    const PreviewResult unsupportedSemanticResult = retriever.fetchPreview("/tmp/package.deb",
+                                                                           SearchType::Semantic);
+    QVERIFY(unsupportedSemanticResult.status() == PreviewStatus::NotIndexed);
+    QVERIFY(unsupportedSemanticResult.content().isEmpty());
+    QCOMPARE(unsupportedSemanticResult.charCount(), 0);
+    QCOMPARE(unsupportedSemanticResult.keywordOffset(), -1);
+}
+
 void tst_ContentRetriever::fetchPreview_offsetBeyondContent()
 {
     QTemporaryDir tempDir;
@@ -330,6 +360,7 @@ void tst_ContentRetriever::fetchPreview_offsetBeyondContent()
     const PreviewResult result = retriever.fetchPreview("/tmp/doc-a.txt",
                                                          SearchType::Content,
                                                          options);
+    QVERIFY(result.status() == PreviewStatus::Success);
     QVERIFY(result.content().isEmpty());
     QCOMPARE(result.charCount(), QString("hello world from content index").size());
     QCOMPARE(result.keywordOffset(), -1);
@@ -357,6 +388,7 @@ void tst_ContentRetriever::fetchPreview_unlimitedNoKeyword()
         const PreviewResult result = retriever.fetchPreview("/tmp/doc-a.txt",
                                                              SearchType::Content,
                                                              options);
+        QVERIFY(result.status() == PreviewStatus::Success);
         QCOMPARE(result.content(), QString("hello world from content index"));
         QCOMPARE(result.charCount(), QString("hello world from content index").size());
         QCOMPARE(result.keywordOffset(), -1);
@@ -372,6 +404,7 @@ void tst_ContentRetriever::fetchPreview_unlimitedNoKeyword()
         const PreviewResult result = retriever.fetchPreview("/tmp/doc-a.txt",
                                                              SearchType::Content,
                                                              options);
+        QVERIFY(result.status() == PreviewStatus::Success);
         QCOMPARE(result.content(), QString("world from content index"));
         QCOMPARE(result.charCount(), QString("hello world from content index").size());
         QCOMPARE(result.keywordOffset(), -1);

autotests/dfm-search-tests/tst_search_output.cpp

@@ -29,9 +29,10 @@
 #include <lucene++/KeywordAnalyzer.h>
 #include <lucene++/LuceneHeaders.h>
 
 #include "output/json_output.h"
 #include "output/text_output.h"
+#include "preview_command.h"
 #include "preview_output_utils.h"
 
 using namespace DFMSEARCH;
 using namespace Lucene;
@@ -120,8 +121,9 @@
 {
     Q_OBJECT
 
 private Q_SLOTS:
     void previewOutputHelpers_includeCharCount();
+    void previewCommand_failsForUnindexedPath();
     void jsonOutput_contentAndFilenameCharCountContract();
     void jsonOutput_ocrAndSemanticCharCountContract();
     void textOutput_contentAndSemanticCharCountContract();
@@ -156,6 +158,31 @@
     QVERIFY(text.contains("world from"));
 }
 
+void tst_SearchOutput::previewCommand_failsForUnindexedPath()
+{
+    QTemporaryDir tempDir;
+    QVERIFY(tempDir.isValid());
+
+    const QString contentIndexDir = tempDir.path() + "/content-index";
+    createIndex(contentIndexDir, SearchType::Content);
+
+    ContentRetriever retriever;
+    retriever.setIndexDirectory(SearchType::Content, contentIndexDir);
+
+    SearchCliConfig config;
+    config.subcommand = "preview";
+    config.searchType = SearchType::Content;
+    config.searchPath = "/tmp/doc-a.txt,/tmp/missing.txt";
+    config.jsonOutput = true;
+
+    const PreviewCommandResult result = dfmsearch::runPreviewCommand(config, retriever);
+    QCOMPARE(result.exitCode, 1);
+    QVERIFY(result.stdoutText.isEmpty());
+    QVERIFY(result.stderrText.contains("Error: preview requires indexed content for:"));
+    QVERIFY(result.stderrText.contains("/tmp/missing.txt"));
+    QVERIFY(!result.stderrText.contains("/tmp/doc-a.txt"));
+}
+
 void tst_SearchOutput::jsonOutput_contentAndFilenameCharCountContract()
 {
     SearchOptions options;

include/dfm-search/dfm-search/contentretriever.h

@@ -80,11 +80,16 @@ class PreviewOptions
     QSharedDataPointer<PreviewOptionsPrivate> d;
 };
 
+enum class PreviewStatus {
+    Success = 0,
+    NotIndexed = 1,
+};
+
 /**
  * @brief Result of a preview extraction (Pimpl-based, ABI-stable)
  *
- * Contains the extracted content snippet and the position of the keyword
- * in the full document text (-1 if no keyword or not matched).
+ * Contains the extraction status, content snippet, and the position of the
+ * keyword in the full document text (-1 if no keyword or not matched).
  *
  * Supports implicit sharing (COW) via QSharedDataPointer.
  */
@@ -98,6 +103,7 @@ class PreviewResult
     PreviewResult(PreviewResult &&other) noexcept = default;
     PreviewResult &operator=(PreviewResult &&other) noexcept = default;
 
+    PreviewStatus status() const;
     QString content() const;
     int charCount() const;
     int keywordOffset() const;

src/dfm-search/dfm-search-client/CMakeLists.txt

@@ -6,6 +6,8 @@ set(SRCS
     main.cpp
     cli_options.cpp
     cli_options.h
+    preview_command.cpp
+    preview_command.h
     preview_output_utils.cpp
     preview_output_utils.h
     time_parser.cpp

src/dfm-search/dfm-search-client/main.cpp

@@ -2,25 +2,21 @@
 //
 // SPDX-License-Identifier: GPL-3.0-or-later
 
 #include <QCoreApplication>
 #include <QDebug>
-#include <QJsonDocument>
-#include <QJsonObject>
-#include <QJsonArray>
-#include <QTextStream>
 
 #include <dfm-search/searchengine.h>
 #include <dfm-search/searchfactory.h>
 #include <dfm-search/searchquery.h>
 #include <dfm-search/searchoptions.h>
 #include <dfm-search/filenamesearchapi.h>
 #include <dfm-search/contentsearchapi.h>
 #include <dfm-search/ocrtextsearchapi.h>
 #include <dfm-search/semanticsearcher.h>
 #include <dfm-search/contentretriever.h>
 
 #include "cli_options.h"
-#include "preview_output_utils.h"
+#include "preview_command.h"
 #include "output/text_output.h"
 #include "output/json_output.h"
 
@@ -197,54 +193,14 @@
     // Preview subcommand: fetch content preview on demand
     if (config.subcommand == "preview") {
         DFMSEARCH::ContentRetriever retriever;
-        DFMSEARCH::PreviewOptions previewOptions;
-        previewOptions.setOffset(config.offset);
-        // 无 keyword 且未显式设置 --max-preview：maxLength=0 表示无限制（返回全文）
-        // 有 keyword 或显式设置了 --max-preview：使用 maxPreviewLength 值
-        if (config.keyword.isEmpty() && !config.maxPreviewSet) {
-            previewOptions.setMaxLength(0);
-        } else {
-            previewOptions.setMaxLength(config.maxPreviewLength);
+        const PreviewCommandResult previewResult = runPreviewCommand(config, retriever);
+        if (!previewResult.stderrText.isEmpty()) {
+            std::cerr << previewResult.stderrText.toStdString();
         }
-        previewOptions.setKeyword(config.keyword);
-
-        // Paths are stored as comma-separated in config.searchPath
-#if QT_VERSION >= QT_VERSION_CHECK(5, 15, 0)
-        QStringList paths = config.searchPath.split(',', Qt::SkipEmptyParts);
-#else
-        QStringList paths = config.searchPath.split(',', QString::SkipEmptyParts);
-#endif
-
-        if (config.jsonOutput) {
-            // JSON output
-            QJsonObject root;
-            root["type"] = "preview";
-            root["searchType"] = (config.searchType == SearchType::Content) ? "content"
-                : (config.searchType == SearchType::Ocr) ? "ocr" : "semantic";
-            root["keyword"] = config.keyword;
-            root["offset"] = config.offset;
-            root["maxLength"] = previewOptions.maxLength();
-
-            QJsonArray results;
-            for (const QString &path : paths) {
-                DFMSEARCH::PreviewResult result = retriever.fetchPreview(path, config.searchType, previewOptions);
-                results.append(previewResultToJson(path, result));
-            }
-
-            root["totalResults"] = results.size();
-            root["results"] = results;
-
-            QJsonDocument doc(root);
-            std::cout << doc.toJson(QJsonDocument::Indented).toStdString() << std::endl;
-        } else {
-            // Text output
-            QTextStream out(stdout);
-            for (const QString &path : paths) {
-                DFMSEARCH::PreviewResult result = retriever.fetchPreview(path, config.searchType, previewOptions);
-                writePreviewResultText(out, path, result);
-            }
+        if (!previewResult.stdoutText.isEmpty()) {
+            std::cout << previewResult.stdoutText.toStdString();
         }
-        return 0;
+        return previewResult.exitCode;
     }
 
     // Semantic search mode