Remove code reading header in spectrapply

- Remove the code inserted to fix issue #170; fixes issue #216.
- Add tests to the torture.R script checking if the #170 error still happens.

R/functions-OnDiskMSnExp.R

@@ -246,7 +246,7 @@ precursorValue_OnDiskMSnExp <- function(object, column) {
     ## Reading the header for the selecte spectra. This is to avoid getting
     ## "memory not mapped" errors when reading mz and intensity values from
     ## certain mzML files (issue #170).
-    hd_spectra <- mzR::header(fileh, fData$spIdx)
+    ## hd_spectra <- mzR::header(fileh, fData$spIdx)
     ## Process MS1 and MSn separately
     if (length(msLevel1) >= 1) {
         ms1fd <- fData[msLevel1, , drop = FALSE]

inst/scripts/torture.R

@@ -22,3 +22,23 @@ for (i in 1:7500) {
     sp <- spectra(res)
 }
 
+## Torture test to check for issue #170
+
+library(doParallel)
+registerDoParallel(2)
+register(DoparParam())
+
+options(mzR = list(default_backend = "Ramp"))
+
+fls <- dir("/Users/jo/data/2016/2016_06/", pattern = "mzML", full.names = TRUE)
+set.seed(123)
+if (length(fls)) {
+    ## Randomly grep 12 of them load them and extract spectra.
+    for (i in 1:5000) {
+        if (i %% 200 == 0)
+            cat(i, "\n")
+        fls_sub <- sample(fls, 12)
+        od <- readMSData2(fls_sub, verbose = FALSE)
+        spctr <- spectra(od)
+    }
+}