From f050dd08f5e4b145f0365c28da7310f65322694d Mon Sep 17 00:00:00 2001
From: Cheng-Ling Lai <jameslai.tech@gmail.com>
Date: Tue, 17 Mar 2026 14:05:28 +0800
Subject: [PATCH] Reorganize CmdFileHash

---
 client/snbk/CmdFileHash.cc | 73 ++++++++++++++++++++++++--------------
 client/snbk/CmdFileHash.h  |  8 ++---
 client/snbk/TheBigThing.cc |  9 ++---
 3 files changed, 55 insertions(+), 35 deletions(-)

diff --git a/client/snbk/CmdFileHash.cc b/client/snbk/CmdFileHash.cc
index a857c1b2..e8b67ffb 100644
--- a/client/snbk/CmdFileHash.cc
+++ b/client/snbk/CmdFileHash.cc
@@ -22,6 +22,7 @@
 
 #include <boost/algorithm/string.hpp>
 
+#include <snapper/AppUtil.h>
 #include <snapper/Exception.h>
 #include <snapper/LoggerImpl.h>
 #include <snapper/SystemCmd.h>
@@ -36,23 +37,59 @@ namespace snapper
 
 
     CmdFileHash::CmdFileHash(const Shell& shell, const string& chksum_bin,
-                             const string& path)
+                             const string& path, bool allow_failure)
         : path(path)
     {
 	SystemCmd::Args cmd_args = { chksum_bin, "--", path };
 	SystemCmd cmd(shellify(shell, cmd_args));
 
-	if (cmd.retcode() != 0)
+	try
 	{
-	    y2err("command '" << cmd.cmd() << "' failed: " << cmd.retcode());
-	    for (const string& tmp : cmd.get_stdout())
-		y2err(tmp);
-	    for (const string& tmp : cmd.get_stderr())
-		y2err(tmp);
+	    if (cmd.retcode() != 0)
+	    {
+		y2err("command '" << cmd.cmd() << "' failed: " << cmd.retcode());
+		for (const string& tmp : cmd.get_stdout())
+		    y2err(tmp);
+		for (const string& tmp : cmd.get_stderr())
+		    y2err(tmp);
+
+		SN_THROW(Exception(_("Failed to compute file hash.")));
+	    }
+	    else
+	    {
+		// Check if the hash utility returns 1 line exactly
+		vector<string> cmd_outputs = cmd.get_stdout();
+		if (cmd_outputs.size() != 1)
+		{
+		    y2err(sformat("Expected 1 line, but %lu lines were received from %s.",
+		                  cmd_outputs.size(), chksum_bin.c_str()));
+		    SN_THROW(Exception(_("Unexpected output from the hash utility.")));
+		}
+
+		// Parse the hash output
+		vector<string> parts;
+		const string& line = cmd_outputs[0];
+		boost::split(parts, line, boost::is_any_of(" "),
+		             boost::token_compress_on);
+		if (parts.size() != 2)
+		{
+		    y2err("Invalid hash string: " << line);
+		    SN_THROW(Exception(_("Invalid hash output format.")));
+		}
+
+		hash = parts[0];
+	    }
 	}
-	else
+	catch (const Exception& e)
 	{
-	    parse(cmd.get_stdout());
+	    if (!allow_failure)
+	    {
+		SN_THROW(e);
+	    }
+	    else
+	    {
+		y2err(e);
+	    }
 	}
 
 	y2mil(*this);
@@ -61,24 +98,6 @@ namespace snapper
 
     const string& CmdFileHash::get_hash() const { return hash; }
 
-    void CmdFileHash::parse(const vector<string>& lines)
-    {
-	for (const string& line : lines)
-	{
-	    vector<string> parts;
-	    boost::split(parts, line, boost::is_any_of(" "), boost::token_compress_on);
-	    if (parts.size() != 2)
-	    {
-		y2err("Invalid hash string: " << line);
-		SN_THROW(Exception(_("Invalid hash output format.")));
-	    }
-
-	    hash = parts[0];
-	    break;
-	}
-    }
-
-
     std::ostream& operator<<(std::ostream& s, const CmdFileHash& cmd_filehash)
     {
 	s << "path: " << cmd_filehash.path << " hash: " << cmd_filehash.hash << '\n';
diff --git a/client/snbk/CmdFileHash.h b/client/snbk/CmdFileHash.h
index 8325dbc0..0a6dacc7 100644
--- a/client/snbk/CmdFileHash.h
+++ b/client/snbk/CmdFileHash.h
@@ -34,13 +34,15 @@ namespace snapper
 
     /**
      * Find the hash of the file at the given path.
-     * If an error occurs, the hash is set to an empty string.
+     * If `allow_failure` is `true`, errors are ignored and the hash is set to an empty
+     * string.
      */
     class CmdFileHash
     {
     public:
 
-	CmdFileHash(const Shell& shell, const string& chksum_bin, const string& path);
+	CmdFileHash(const Shell& shell, const string& chksum_bin, const string& path,
+	            bool allow_failure);
 
 	const string& get_hash() const;
 
@@ -50,8 +52,6 @@ namespace snapper
 
 	const string path;
 	string hash;
-
-	void parse(const std::vector<string>& lines);
     };
 
 
diff --git a/client/snbk/TheBigThing.cc b/client/snbk/TheBigThing.cc
index 4d20e5c6..5effad66 100644
--- a/client/snbk/TheBigThing.cc
+++ b/client/snbk/TheBigThing.cc
@@ -518,7 +518,8 @@ namespace snapper
 
 	    // Find the hash of info.xml
 	    CmdFileHash cmd_filehash(shell_source, SHA256SUM_BIN,
-	                             source_snapshot_dir(snapper, num) + "/info.xml");
+	                             source_snapshot_dir(snapper, num) + "/info.xml",
+	                             false);
 	    the_big_thing.source_meta_hash = cmd_filehash.get_hash();
 
 	    the_big_things.push_back(the_big_thing);
@@ -618,9 +619,9 @@ namespace snapper
 		it->target_creation_time = extra.get_creation_time();
 
 		// Find the hash of info.xml
-		CmdFileHash cmd_filehash(shell_target, backup_config.target_sha256sum_bin,
-		                         target_snapshot_dir(backup_config, num) +
-		                             "/info.xml");
+		CmdFileHash cmd_filehash(
+		    shell_target, backup_config.target_sha256sum_bin,
+		    target_snapshot_dir(backup_config, num) + "/info.xml", true);
 		it->target_meta_hash = cmd_filehash.get_hash();
 
 		if (it->source_state == TheBigThing::SourceState::READ_ONLY &&
-- 
2.47.3