From e00f02359980ea91cd760fbf3a462f7b7efa6bb8 Mon Sep 17 00:00:00 2001
From: Veloman Yunkan <veloman.yunkan@gmail.com>
Date: Wed, 26 Jun 2024 11:17:41 +0400
Subject: [PATCH] DownloadManager::checkThatBookCanBeDownloaded()

Separated checks that can be performed early (independent of aria2c
services). When the download initiation is converted to a 2-stage
procedure (similar to how it was done for pausing/resuming/cancelling
a download) those checks better be performed synchronously in the main
thread.
---
 src/contentmanager.cpp     | 1 +
 src/downloadmanagement.cpp | 5 ++++-
 src/downloadmanagement.h   | 4 ++++
 3 files changed, 9 insertions(+), 1 deletion(-)

diff --git a/src/contentmanager.cpp b/src/contentmanager.cpp
index 4178b47..065a8b1 100644
--- a/src/contentmanager.cpp
+++ b/src/contentmanager.cpp
@@ -513,6 +513,7 @@ void ContentManager::downloadBook(const QString &id)
 
     std::string downloadId;
     try {
+        DownloadManager::checkThatBookCanBeDownloaded(book, downloadPath);
         downloadId = DownloadManager::startDownload(book, downloadPath);
     } catch ( const KiwixAppError& err ) {
         showErrorBox(err, mp_view);
diff --git a/src/downloadmanagement.cpp b/src/downloadmanagement.cpp
index 2be8c8b..20fbab0 100644
--- a/src/downloadmanagement.cpp
+++ b/src/downloadmanagement.cpp
@@ -257,13 +257,16 @@ void checkThatBookCanBeSaved(const kiwix::Book& book, QString targetDir)
 } // unnamed namespace
 
 
-std::string DownloadManager::startDownload(const kiwix::Book& book, const QString& downloadDirPath)
+void DownloadManager::checkThatBookCanBeDownloaded(const kiwix::Book& book, const QString& downloadDirPath)
 {
     if ( ! DownloadManager::downloadingFunctionalityAvailable() )
         throwDownloadUnavailableError();
 
     checkThatBookCanBeSaved(book, downloadDirPath);
+}
 
+std::string DownloadManager::startDownload(const kiwix::Book& book, const QString& downloadDirPath)
+{
     typedef std::vector<std::pair<std::string, std::string>> DownloadOptions;
 
     const std::string& url = book.getUrl();
diff --git a/src/downloadmanagement.h b/src/downloadmanagement.h
index 0509b78..07d0e73 100644
--- a/src/downloadmanagement.h
+++ b/src/downloadmanagement.h
@@ -156,6 +156,10 @@ public: // functions
 
     void addRequest(Action action, QString bookId);
 
+    // Throws a KiwixAppError in case of any foreseeable problem preventing a
+    // successful download
+    void checkThatBookCanBeDownloaded(const kiwix::Book& book, const QString& downloadDirPath);
+
     // returns the download id
     std::string startDownload(const kiwix::Book& book, const QString& downloadDirPath);
     void removeDownload(QString bookId);