From: Joel Rosdahl <joel@rosdahl.net>
Date: Mon, 3 Aug 2020 18:03:13 +0000 (+0200)
Subject: Replace fatal function with throwing FatalError exception explicitly
X-Git-Tag: v4.0~228
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=adfca03bb4f9f4d53fa36aed29a64832ed2661c8;p=thirdparty%2Fccache.git

Replace fatal function with throwing FatalError exception explicitly

I think that this improves code readability since it’s more clear what
the code flow is.
---

diff --git a/src/Logging.cpp b/src/Logging.cpp
index 65072a8c0..b8ee4a395 100644
--- a/src/Logging.cpp
+++ b/src/Logging.cpp
@@ -68,7 +68,7 @@ bool debug_log_enabled = false;
 [[noreturn]] void
 print_fatal_error_and_exit()
 {
-  // Note: Can't call fatal() since that would lead to recursion.
+  // Note: Can't throw FatalError since that would lead to recursion.
   fmt::print(stderr,
              "ccache: error: Failed to write to {}: {}\n",
              logfile_path,
diff --git a/src/TemporaryFile.cpp b/src/TemporaryFile.cpp
index 3acc30460..803ad9e8b 100644
--- a/src/TemporaryFile.cpp
+++ b/src/TemporaryFile.cpp
@@ -63,12 +63,14 @@ TemporaryFile::TemporaryFile(string_view path_prefix)
   if (!initialize(path_prefix) && errno == ENOENT) {
     auto dir = Util::dir_name(path);
     if (!Util::create_dir(dir)) {
-      fatal("Failed to create directory {}: {}", dir, strerror(errno));
+      throw FatalError(
+        "Failed to create directory {}: {}", dir, strerror(errno));
     }
     initialize(path_prefix);
   }
   if (!fd) {
-    fatal("Failed to create temporary file for {}: {}", path, strerror(errno));
+    throw FatalError(
+      "Failed to create temporary file for {}: {}", path, strerror(errno));
   }
 
   Util::set_cloexec_flag(*fd);
diff --git a/src/Util.cpp b/src/Util.cpp
index 05735e356..b28f536f5 100644
--- a/src/Util.cpp
+++ b/src/Util.cpp
@@ -634,7 +634,8 @@ get_home_directory()
     }
   }
 #endif
-  fatal("Could not determine home directory from $HOME or getpwuid(3)");
+  throw FatalError(
+    "Could not determine home directory from $HOME or getpwuid(3)");
 }
 
 const char*
diff --git a/src/ccache.cpp b/src/ccache.cpp
index e51e8da43..34b573f93 100644
--- a/src/ccache.cpp
+++ b/src/ccache.cpp
@@ -154,7 +154,7 @@ add_prefix(const Context& ctx, Args& args, const std::string& prefix_command)
   for (const auto& word : Util::split_into_strings(prefix_command, " ")) {
     std::string path = find_executable(ctx, word, MYNAME);
     if (path.empty()) {
-      fatal("{}: {}", word, strerror(errno));
+      throw FatalError("{}: {}", word, strerror(errno));
     }
 
     prefix.push_back(path);
@@ -1713,11 +1713,12 @@ find_compiler(Context& ctx, const char* const* argv)
 
   std::string compiler = find_executable(ctx, base, MYNAME);
   if (compiler.empty()) {
-    fatal("Could not find compiler \"{}\" in PATH", base);
+    throw FatalError("Could not find compiler \"{}\" in PATH", base);
   }
   if (compiler == argv[0]) {
-    fatal("Recursive invocation (the name of the ccache binary must be \"{}\")",
-          MYNAME);
+    throw FatalError(
+      "Recursive invocation (the name of the ccache binary must be \"{}\")",
+      MYNAME);
   }
   ctx.orig_args[0] = compiler;
 }
@@ -1775,13 +1776,14 @@ set_up_config(Config& config)
     MTR_END("config", "conf_read_secondary");
 
     if (config.cache_dir().empty()) {
-      fatal("configuration setting \"cache_dir\" must not be the empty string");
+      throw FatalError(
+        "configuration setting \"cache_dir\" must not be the empty string");
     }
     if ((p = getenv("CCACHE_DIR"))) {
       config.set_cache_dir(p);
     }
     if (config.cache_dir().empty()) {
-      fatal("CCACHE_DIR must not be the empty string");
+      throw FatalError("CCACHE_DIR must not be the empty string");
     }
 
     config.set_primary_config_path(
@@ -1924,7 +1926,7 @@ cache_compilation(int argc, const char* const* argv)
     log("Executing {}", Util::format_argv_for_logging(execv_argv.data()));
     ctx.reset(); // Dump debug logs last thing before executing.
     execv(execv_argv[0], const_cast<char* const*>(execv_argv.data()));
-    fatal("execv of {} failed: {}", execv_argv[0], strerror(errno));
+    throw FatalError("execv of {} failed: {}", execv_argv[0], strerror(errno));
   }
 }
 
diff --git a/src/exceptions.hpp b/src/exceptions.hpp
index 1d70ad53d..d6ce7e9a2 100644
--- a/src/exceptions.hpp
+++ b/src/exceptions.hpp
@@ -47,9 +47,24 @@ class Error : public ErrorBase
 // with a non-zero exit code.
 class FatalError : public ErrorBase
 {
-  using ErrorBase::ErrorBase;
+public:
+  // Special case: If given only one string, don't parse it as a format string.
+  FatalError(const std::string& message);
+
+  // `args` are forwarded to `fmt::format`.
+  template<typename... T> inline FatalError(T&&... args);
 };
 
+inline FatalError::FatalError(const std::string& message) : ErrorBase(message)
+{
+}
+
+template<typename... T>
+inline FatalError::FatalError(T&&... args)
+  : ErrorBase(fmt::format(std::forward<T>(args)...))
+{
+}
+
 // Throw a Failure if ccache did not succeed in getting or putting a result in
 // the cache. If `exit_code` is set, just exit with that code directly,
 // otherwise execute the real compiler and exit with its exit code. Also updates
@@ -83,12 +98,3 @@ Failure::stat() const
 {
   return m_stat;
 }
-
-// Something went badly wrong! Print a message to stderr and exit with non-zero
-// exit code. `args` are forwarded to `fmt::format`.
-template<typename... T>
-[[noreturn]] inline void
-fatal(T&&... args)
-{
-  throw FatalError(fmt::format(std::forward<T>(args)...));
-}
diff --git a/src/execute.cpp b/src/execute.cpp
index 77789ac2d..7b647b7b1 100644
--- a/src/execute.cpp
+++ b/src/execute.cpp
@@ -166,7 +166,7 @@ execute(const char* const* argv, Fd&& fd_out, Fd&& fd_err, pid_t* pid)
   }
 
   if (*pid == -1) {
-    fatal("Failed to fork: {}", strerror(errno));
+    throw FatalError("Failed to fork: {}", strerror(errno));
   }
 
   if (*pid == 0) {
@@ -183,7 +183,7 @@ execute(const char* const* argv, Fd&& fd_out, Fd&& fd_err, pid_t* pid)
 
   int status;
   if (waitpid(*pid, &status, 0) != *pid) {
-    fatal("waitpid failed: {}", strerror(errno));
+    throw FatalError("waitpid failed: {}", strerror(errno));
   }
 
   {
diff --git a/src/hashutil.cpp b/src/hashutil.cpp
index 0a64d024e..9cc768008 100644
--- a/src/hashutil.cpp
+++ b/src/hashutil.cpp
@@ -466,12 +466,12 @@ hash_command_output(Hash& hash,
 #else
   int pipefd[2];
   if (pipe(pipefd) == -1) {
-    fatal("pipe failed: {}", strerror(errno));
+    throw FatalError("pipe failed: {}", strerror(errno));
   }
 
   pid_t pid = fork();
   if (pid == -1) {
-    fatal("fork failed: {}", strerror(errno));
+    throw FatalError("fork failed: {}", strerror(errno));
   }
 
   if (pid == 0) {