Content Search: `leaf0_missing` logic isn't reliable

[markpbaggett]

For content search, we don't have a way to know if pages start at 0 or 1.

We used to think we could rely on "leaf0_missing": false but that doesn't always work. Here is an example:

https://ia601306.us.archive.org/fulltext/inside.php?item_id=gray-diary&doc=GrayDiary&path=/33/items/gray-diary&q=Virginia

[glenrobson]

I've been having a look at the Book reader JSON for #133:

https://ia800309.us.archive.org/BookReader/BookReaderJSIA.php?id=bub_gb_3Kt5kiw9KYcC&itemPath=/14/items/bub_gb_3Kt5kiw9KYcC&server=ia800309.us.archive.org&format=jsonp&subPrefix=bub_gb_3Kt5kiw9KYcC

I had forgotten but this splits a book into opening page and spread (page 1, page2) final page. I wonder if this is the source of the leaf0_missing? Example json where first item contains 1 page second item in data contains 2 items pageSide left and pageSide right:

"data": [
    [
        {
            "width": 1976,
            "height": 2500,
            "uri": "https://ia800309.us.archive.org/BookReader/BookReaderImages.php?zip=/14/items/bub_gb_3Kt5kiw9KYcC/bub_gb_3Kt5kiw9KYcC_jp2.zip&file=bub_gb_3Kt5kiw9KYcC_jp2/bub_gb_3Kt5kiw9KYcC_0000.jp2&id=bub_gb_3Kt5kiw9KYcC",
            "leafNum": 0,
            "pageType": "Normal",
            "pageSide": "R"
        }
    ],
    [
        {
            "width": 1996,
            "height": 2500,
            "uri": "https://ia800309.us.archive.org/BookReader/BookReaderImages.php?zip=/14/items/bub_gb_3Kt5kiw9KYcC/bub_gb_3Kt5kiw9KYcC_jp2.zip&file=bub_gb_3Kt5kiw9KYcC_jp2/bub_gb_3Kt5kiw9KYcC_0001.jp2&id=bub_gb_3Kt5kiw9KYcC",
            "leafNum": 1,
            "pageType": "Normal",
            "pageSide": "L"
        },
        {
            "width": 1972,
            "height": 2500,
            "uri": "https://ia800309.us.archive.org/BookReader/BookReaderImages.php?zip=/14/items/bub_gb_3Kt5kiw9KYcC/bub_gb_3Kt5kiw9KYcC_jp2.zip&file=bub_gb_3Kt5kiw9KYcC_jp2/bub_gb_3Kt5kiw9KYcC_0002.jp2&id=bub_gb_3Kt5kiw9KYcC",
            "leafNum": 2,
            "pageType": "Normal",
            "pageSide": "R"
        }
    ],
    [
        {
            "width": 1980,
            "height": 2500,
            "uri": "https://ia800309.us.archive.org/BookReader/BookReaderImages.php?zip=/14/items/bub_gb_3Kt5kiw9KYcC/bub_gb_3Kt5kiw9KYcC_jp2.zip&file=bub_gb_3Kt5kiw9KYcC_jp2/bub_gb_3Kt5kiw9KYcC_0003.jp2&id=bub_gb_3Kt5kiw9KYcC",
            "leafNum": 3,
            "pageType": "Normal",
            "pageSide": "L"
        },
        {
            "width": 1994,
            "height": 2500,
            "uri": "https://ia800309.us.archive.org/BookReader/BookReaderImages.php?zip=/14/items/bub_gb_3Kt5kiw9KYcC/bub_gb_3Kt5kiw9KYcC_jp2.zip&file=bub_gb_3Kt5kiw9KYcC_jp2/bub_gb_3Kt5kiw9KYcC_0004.jp2&id=bub_gb_3Kt5kiw9KYcC",
            "leafNum": 4,
            "pageType": "Title",
            "pageSide": "R"
        }
    ]

[glenrobson]

Book reader link for Gray Diary:

https://ia601306.us.archive.org/BookReader/BookReaderJSIA.php?id=gray-diary&itemPath=/33/items/gray-diary&server=ia601306.us.archive.org&format=jsonp&subPrefix=GrayDiary

also has a opening page:

"data": [
                [
                    {
                        "width": 2225,
                        "height": 3650,
                        "uri": "https://ia601306.us.archive.org/BookReader/BookReaderImages.php?zip=/33/items/gray-diary/GrayDiary_jp2.zip&file=GrayDiary_jp2/GrayDiary_0000.jp2&id=gray-diary",
                        "leafNum": 0,
                        "pageType": "Normal",
                        "ppi": 400,
                        "pageSide": "R"
                    }
                ],
                [
                    {
                        "width": 2225,
                        "height": 3650,
                        "uri": "https://ia601306.us.archive.org/BookReader/BookReaderImages.php?zip=/33/items/gray-diary/GrayDiary_jp2.zip&file=GrayDiary_jp2/GrayDiary_0001.jp2&id=gray-diary",
                        "leafNum": 1,
                        "pageType": "Normal",
                        "ppi": 400,
                        "pageSide": "L"
                    },
                    {
                        "width": 2225,
                        "height": 3650,
                        "uri": "https://ia601306.us.archive.org/BookReader/BookReaderImages.php?zip=/33/items/gray-diary/GrayDiary_jp2.zip&file=GrayDiary_jp2/GrayDiary_0002.jp2&id=gray-diary",
                        "leafNum": 2,
                        "pageType": "Normal",
                        "ppi": 400,
                        "pageSide": "R"
                    }
                ],