Prefer std::string::clear where possible (#2467)

This is somewhat more clear and is declared noexcept.

src/curl.cpp

@@ -885,17 +885,17 @@ bool S3fsCurl::FinalCheckSse()
 {
     switch(S3fsCurl::ssetype){
         case sse_type_t::SSE_DISABLE:
-            S3fsCurl::ssekmsid.erase();
+            S3fsCurl::ssekmsid.clear();
             return true;
         case sse_type_t::SSE_S3:
-            S3fsCurl::ssekmsid.erase();
+            S3fsCurl::ssekmsid.clear();
             return true;
         case sse_type_t::SSE_C:
             if(S3fsCurl::sseckeys.empty()){
                 S3FS_PRN_ERR("sse type is SSE-C, but there is no custom key.");
                 return false;
             }
-            S3fsCurl::ssekmsid.erase();
+            S3fsCurl::ssekmsid.clear();
             return true;
         case sse_type_t::SSE_KMS:
             if(S3fsCurl::ssekmsid.empty()){
@@ -3091,7 +3091,7 @@ int S3fsCurl::GetIAMv2ApiToken(const char* token_url, int token_ttl, const char*
         S3FS_PRN_ERR("IAMv2 token url(%s) or ttl_hdr(%s) parameter are wrong.", token_url ? token_url : "null", token_ttl_hdr ? token_ttl_hdr : "null");
         return -EIO;
     }
-    response.erase();
+    response.clear();
     url = token_url;
     if(!CreateCurlHandle()){
         return -EIO;
@@ -3154,7 +3154,7 @@ bool S3fsCurl::GetIAMCredentials(const char* cred_url, const char* iam_v2_token,
         return false;
     }
     url = cred_url;
-    response.erase();
+    response.clear();
 
     // at first set type for handle
     type = REQTYPE::IAMCRED;
@@ -3240,7 +3240,7 @@ bool S3fsCurl::GetIAMRoleFromMetaData(const char* cred_url, const char* iam_v2_t
         return false;
     }
     url = cred_url;
-    token.erase();
+    token.clear();
 
     S3FS_PRN_INFO3("Get IAM Role name");
 

src/fdcache.cpp

@@ -105,7 +105,7 @@ bool FdManager::SetCacheDir(const char* dir)
 bool FdManager::SetCacheCheckOutput(const char* path)
 {
     if(!path || '\0' == path[0]){
-        check_cache_output.erase();
+        check_cache_output.clear();
     }else{
         check_cache_output = path;
     }

src/fdcache_entity.cpp

@@ -180,7 +180,7 @@ void FdEntity::Clear()
             if(-1 == unlink(mirrorpath.c_str())){
                 S3FS_PRN_WARN("failed to remove mirror cache file(%s) by errno(%d).", mirrorpath.c_str(), errno);
             }
-            mirrorpath.erase();
+            mirrorpath.clear();
         }
     }
     pagelist.Init(0, false, false);
@@ -250,7 +250,7 @@ void FdEntity::Close(int fd)
             if(-1 == unlink(mirrorpath.c_str())){
                 S3FS_PRN_WARN("failed to remove mirror cache file(%s) by errno(%d).", mirrorpath.c_str(), errno);
             }
-            mirrorpath.erase();
+            mirrorpath.clear();
         }
     }
 }
@@ -764,7 +764,7 @@ bool FdEntity::RenamePath(const std::string& newpath, std::string& fentmapkey)
 
     }else{
         // does not have cache path
-        fentmapkey.erase();
+        fentmapkey.clear();
         FdManager::MakeRandomTempPath(newpath.c_str(), fentmapkey);
     }
     // set new path
@@ -1156,8 +1156,8 @@ int FdEntity::NoCacheLoadAndPost(PseudoFdInfo* pseudo_obj, off_t start, off_t si
         // remove cache files(and cache stat file)
         FdManager::DeleteCacheFile(path.c_str());
         // cache file path does not use no more.
-        cachepath.erase();
+        cachepath.clear();
-        mirrorpath.erase();
+        mirrorpath.clear();
     }
 
     // Change entity key in manager mapping

src/fdcache_fdinfo.cpp

@@ -251,7 +251,7 @@ bool PseudoFdInfo::ResetUploadInfo(AutoLock::Type type)
 {
     AutoLock auto_lock(&upload_list_lock, type);
 
-    upload_id.erase();
+    upload_id.clear();
     upload_list.clear();
     instruct_count  = 0;
     completed_count = 0;

src/s3fs.cpp

@@ -902,7 +902,7 @@ bool get_object_sse_type(const char* path, sse_type_t& ssetype, std::string& sse
     }
 
     ssetype = sse_type_t::SSE_DISABLE;
-    ssevalue.erase();
+    ssevalue.clear();
     for(headers_t::iterator iter = meta.begin(); iter != meta.end(); ++iter){
         std::string key = (*iter).first;
         if(0 == strcasecmp(key.c_str(), "x-amz-server-side-encryption") && 0 == strcasecmp((*iter).second.c_str(), "AES256")){
@@ -3601,7 +3601,7 @@ static bool get_meta_xattr_value(const char* path, std::string& rawvalue)
     }
     S3FS_PRN_DBG("[path=%s]", path);
 
-    rawvalue.erase();
+    rawvalue.clear();
 
     headers_t meta;
     if(0 != get_object_attribute(path, nullptr, &meta)){
@@ -3634,7 +3634,7 @@ static bool get_parent_meta_xattr_value(const char* path, std::string& rawvalue)
 
 static bool get_xattr_posix_key_value(const char* path, std::string& xattrvalue, bool default_key)
 {
-    xattrvalue.erase();
+    xattrvalue.clear();
 
     std::string rawvalue;
     if(!get_meta_xattr_value(path, rawvalue)){
@@ -3673,7 +3673,7 @@ static bool build_inherited_xattr_value(const char* path, std::string& xattrvalu
 {
     S3FS_PRN_DBG("[path=%s]", path);
 
-    xattrvalue.erase();
+    xattrvalue.clear();
 
     if(0 == strcmp(path, "/") || 0 == strcmp(path, ".")){
         // path is mount point, thus does not have parent.

src/s3fs_cred.cpp

@@ -1175,7 +1175,7 @@ bool S3fsCred::CheckIAMCredentialUpdate(std::string* access_key_id, std::string*
         if(IsIBMIAMAuth() || IsSetExtCredLib() || is_ecs || is_use_session_token || IsSetIAMRole(AutoLock::ALREADY_LOCKED)){
             *access_token = AWSAccessToken;
         }else{
-            access_token->erase();
+            access_token->clear();
         }
     }
 

src/s3objlist.cpp

@@ -80,7 +80,7 @@ bool S3ObjList::insert(const char* name, const char* etag, bool is_dir)
     // Add object
     if(objects.end() != (iter = objects.find(newname))){
         // Found same object --> update information.
-        (*iter).second.normalname.erase();
+        (*iter).second.normalname.clear();
         (*iter).second.orgname = orgname;
         (*iter).second.is_dir  = is_dir;
         if(etag){
@@ -113,8 +113,8 @@ bool S3ObjList::insert_normalized(const char* name, const char* normalized, bool
     s3obj_t::iterator iter;
     if(objects.end() != (iter = objects.find(name))){
         // found name --> over write
-        iter->second.orgname.erase();
+        iter->second.orgname.clear();
-        iter->second.etag.erase();
+        iter->second.etag.clear();
         iter->second.normalname = normalized;
         iter->second.is_dir     = is_dir;
     }else{

src/types.h

@@ -149,7 +149,7 @@ struct etagpair
 
     void clear()
     {
-        etag.erase();
+        etag.clear();
         part_num = -1;
     }
 };

test/write_multiblock.cc

@@ -109,7 +109,7 @@ static bool parse_string(const char* pstr, char delim, strlist_t& strlist)
             strAll = strAll.substr(pos + 1);
         }else{
             strlist.push_back(strAll);
-            strAll.erase();
+            strAll.clear();
         }
     }
     return true;