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Update open FileDescs at deregistration resulting from delete, rename or register.

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This commit is contained in:
David Brown 2016-11-30 18:13:32 +00:00
parent 67e4848eb7
commit b16e82f866
6 changed files with 202 additions and 10 deletions
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52
src/runtime/Files.Mod
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@ -122,16 +122,51 @@ MODULE Files; (* J. Templ 1.12. 89/12.4.95 Oberon files mapped onto Unix files
name[i] := 0X
END GetTempName;
(* When registering a file, it may turn out that the name we want to use
is aready in use by another File. E.g. the compiler opens and reads
an existing symbol file if present before creating an updated one.
When this happens on Windows, creation of the new file will be blocked
by the presence of the old one because it is in a open state. Further,
on both Unix and Windows systems we want behaviour to match that of
a real Oberon system, where registering the new file has the effect of
unregistering the old file. To simulate this we need to change the old
Files.File back to a temp file. *)
PROCEDURE Deregister(name: ARRAY OF CHAR);
VAR
identity: Platform.FileIdentity;
osfile: File;
error: Platform.ErrorCode;
BEGIN
IF Platform.IdentifyByName(name, identity) = 0 THEN
(* The name we are registering is an already existing file. *)
osfile := files;
WHILE (osfile # NIL) & ~Platform.SameFile(osfile.identity, identity) DO osfile := osfile.next END;
IF osfile # NIL THEN
(* osfile is the FileDesc corresponding to the file name we are hoping
to register. Turn it into a temporary file. *)
ASSERT(~osfile.tempFile); ASSERT(osfile.fd >= 0);
osfile.registerName := osfile.workName;
GetTempName(osfile.registerName, osfile.workName);
osfile.tempFile := TRUE;
osfile.state := open;
error := Platform.Rename(osfile.registerName, osfile.workName);
IF error # 0 THEN
Err("Couldn't rename previous version of file being registered", osfile, error)
END
END
END
END Deregister;
PROCEDURE Create(f: File);
(* Makes sure there is an OS file backing this Oberon file.
Used when more data has been written to an unregistered new file than
buffers can hold, or when registering a new file whose data is all in
buffers. *)
VAR
identity: Platform.FileIdentity;
done: BOOLEAN;
error: Platform.ErrorCode;
err: ARRAY 32 OF CHAR;
done: BOOLEAN;
error: Platform.ErrorCode;
err: ARRAY 32 OF CHAR;
BEGIN
(*
Out.String("Files.Create fd = "); Out.Int(f.fd,1);
@ -149,6 +184,7 @@ MODULE Files; (* J. Templ 1.12. 89/12.4.95 Oberon files mapped onto Unix files
ASSERT(f.state = close);
(* New file with all data in buffers being registered. No need for a
temp file, will just write the buffers to the registerName. *)
Deregister(f.registerName);
f.workName := f.registerName; f.registerName := ""; f.tempFile := FALSE
END;
error := Platform.Unlink(f.workName); (*unlink first to avoid stale NFS handles and to avoid reuse of inodes*)
@ -509,7 +545,10 @@ Especially Length would become fairly complex.
*)
PROCEDURE Delete*(name: ARRAY OF CHAR; VAR res: INTEGER);
BEGIN res := Platform.Unlink(name) END Delete;
BEGIN
Deregister(name);
res := Platform.Unlink(name)
END Delete;
PROCEDURE Rename* (old, new: ARRAY OF CHAR; VAR res: INTEGER);
VAR
@ -531,6 +570,8 @@ Especially Length would become fairly complex.
END;
error := Platform.Rename(old, new);
(* Out.String("Platform.Rename error code "); Out.Int(error,1); Out.Ln; *)
(* TODO, if we already have a FileDesc for old, it ought to be updated
with the new workname. *)
IF ~Platform.DifferentFilesystems(error) THEN
res := error; RETURN
ELSE
@ -572,6 +613,7 @@ Especially Length would become fairly complex.
IF (f.state = create) & (f.registerName # "") THEN f.state := close (* shortcut renaming *) END;
Close(f);
IF f.registerName # "" THEN
Deregister(f.registerName);
Rename(f.workName, f.registerName, errcode);
(*
Out.String("Renamed (for register) f.fd = "); Out.Int(f.fd,1);