ShellPkg: Refine the code logic of 'command history'.

[mirror_edk2.git] / ShellPkg / Application / Shell / Shell.c

diff --git a/ShellPkg/Application/Shell/Shell.c b/ShellPkg/Application/Shell/Shell.c
index 36063227a2d84f723ec8d9ce92028f2f3c16d740..97b8c8d6fbee39a890b6b48216fec8d0dd723a88 100644 (file)
--- a/ShellPkg/Application/Shell/Shell.c
+++ b/ShellPkg/Application/Shell/Shell.c
@@ -1288,13 +1288,40 @@ AddLineToCommandHistory(
   )\r
 {\r
   BUFFER_LIST *Node;\r
+  BUFFER_LIST *Walker;\r
+  UINT16       MaxHistoryCmdCount;\r
+  UINT16       Count;\r
+  \r
+  Count = 0;\r
+  MaxHistoryCmdCount = PcdGet16(PcdShellMaxHistoryCommandCount);\r
+  \r
+  if (MaxHistoryCmdCount == 0) {\r
+    return ;\r
+  }\r
+\r
 \r
   Node = AllocateZeroPool(sizeof(BUFFER_LIST));\r
   ASSERT(Node != NULL);\r
   Node->Buffer = AllocateCopyPool(StrSize(Buffer), Buffer);\r
   ASSERT(Node->Buffer != NULL);\r
 \r
-  InsertTailList(&ShellInfoObject.ViewingSettings.CommandHistory.Link, &Node->Link);\r
+  for ( Walker = (BUFFER_LIST*)GetFirstNode(&ShellInfoObject.ViewingSettings.CommandHistory.Link)\r
+      ; !IsNull(&ShellInfoObject.ViewingSettings.CommandHistory.Link, &Walker->Link)\r
+      ; Walker = (BUFFER_LIST*)GetNextNode(&ShellInfoObject.ViewingSettings.CommandHistory.Link, &Walker->Link)\r
+   ){\r
+    Count++;\r
+  }\r
+  if (Count < MaxHistoryCmdCount){\r
+    InsertTailList(&ShellInfoObject.ViewingSettings.CommandHistory.Link, &Node->Link);\r
+  } else {\r
+    Walker = (BUFFER_LIST*)GetFirstNode(&ShellInfoObject.ViewingSettings.CommandHistory.Link);\r
+    RemoveEntryList(&Walker->Link);\r
+    if (Walker->Buffer != NULL) {\r
+      FreePool(Walker->Buffer);\r
+    }\r
+    FreePool(Walker);\r
+    InsertTailList(&ShellInfoObject.ViewingSettings.CommandHistory.Link, &Node->Link);\r
+  }\r
 }\r
 \r
 /**\r